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mixed signal isp flash mcu family c8051f330/1/2/3/4/5 rev. 1.5 1/06 copyright ? 2006 by silicon laboratories c8051f33x this information applies to a product under dev elopment. its characteristics and specifications are s ubject to change without n otice. analog peripherals - 10-bit adc (?f330/2/4 only) ? up to 200 ksps ? up to 16 external single-ended or differential inputs ? vref from internal vref, external pin or v dd ? internal or external start of conversion source ? built-in temperature sensor - 10-bit current output dac (?f330 only) - comparator ? programmable hysteresis and response time ? configurable as interrupt or reset source ? low current (0.4 a) on-chip debug - on-chip debug circuitry facilitates full speed, non- intrusive in-system debug (no emulator required) - provides breakpoints, single stepping, inspect/modify memory and registers - superior performance to emulation systems using ice-chips, target pods, and sockets - low cost, complete development kit supply voltage 2.7 to 3.6 v - typical operating current: 6.4 ma at 25 mhz; 9 a at 32 khz - typical stop mode current: 0.1 a temperature range: ?40 to +85 c high speed 8051 c core - pipelined instruction architecture; executes 70% of instructions in 1 or 2 system clocks - up to 25 mips throughput with 25 mhz clock - expanded interrupt handler memory - 768 bytes internal data ram (256 + 512) - 8 kb (?f330/1), 4 kb (?f332/3), or 2 kb (?f334/5) flash; in-system progra mmable in 512-byte sec - tors?512 bytes are reserved in the 8 kb devices digital peripherals - 17 port i/o; all 5 v tolerant with high sink current - hardware enhanced uart, smbus?, and enhanced spi? serial ports - four general purpose 16-bit counter/timers - 16-bit programmable counter array (pca) with three capture/compare modules - real time clock mode using pca or timer and exter - nal clock source clock sources - two internal oscillators: ? 24.5 mhz with 2% accuracy supports crystal-less uart operation ? 80/40/20/10 khz low frequency, low power - external oscillator: crystal, rc, c, or clock (1 or 2 pin modes) - can switch between clock s ources on-the-fly; useful in power saving modes 20-pin qfn or 20-pin pdip analog peripherals 2/4/8 kb isp flash 768 b sram por debug circuitry flexible interrupts 8051 cpu (25 mips) digital i/o 24.5 mhz precision internal oscillator high-speed controller core crossbar voltage comparator + - wdt uart smbus pca timer 0 timer 1 timer 2 timer 3 port 0 spi 10-bit current dac low frequency internal oscillator port 1 p2.0 10-bit 200 ksps adc temp sensor a m u x ?f330/2/4 only ?f330 only
c8051f330/1/2/3/4/5 2 rev. 1.5
rev. 1.5 3 c8051f330/1/2/3/4/5 table of contents 1. system overview............ ................ ................ ................. .............. .............. ........... 17 1.1. cip-51? microcontroller core.. ................ ................. .............. .............. ........... 22 1.1.1. fully 8051 compatible...... ................ ................. .............. .............. ........... 22 1.1.2. improved throughput ............ .............. .............. .............. .............. ........... 22 1.1.3. additional features .......... ................ ................. .............. .............. ........... 23 1.2. on-chip memory......... ................ ................. .............. .............. .............. ........... 24 1.3. on-chip debug circuitr y.................... ................. ................ ................. ............. 25 1.4. programmable digital i/o and crossbar ............... ................. ................ ........... 26 1.5. serial ports ............ ................. ................ ................ ................. .............. ........... 26 1.6. programmable counter array ... ................ ................. .............. .............. ........... 27 1.7. 10-bit analog to digital conver ter.................... .............. ............... ........... ......... 28 1.8. comparators ............. ................ ................ ................. .............. .............. ........... 29 1.9. 10-bit current output dac...... ................ ................ ................. .............. ........... 30 2. absolute maximum ratings ........ ................ ................ ................. .............. ........... 31 3. global electrical characteristic s .................. ................. .............. .............. ........... 32 4. pinout and package definitions..... ............... ................. .............. .............. ........... 35 5. 10-bit adc (adc 0, c8051f330/2/4 only) ...... ................. .............. .............. ........... 43 5.1. analog multiplexer ...... ................ ................. .............. .............. .............. ........... 43 5.2. temperature sensor ............ ................. ................ ................. ................ ........... 44 5.3. modes of operation ............. ................. ................ ................. ................ ........... 45 5.3.1. starting a conversion....... ................ ................. .............. .............. ........... 46 5.3.2. tracking modes................ ................ ................. .............. .............. ........... 47 5.3.3. settling time r equirements ................ .............. .............. .............. ........... 48 5.4. programmable window detector ................. .............. .............. .............. ........... 53 5.4.1. window detector in sing le-ended mode .......... .............. .............. ........... 55 5.4.2. window detector in differential mode..... .............. ............... ........... ......... 56 6. 10-bit current mode dac (ida 0, c8051f330 only).............. ............ ........... ......... 59 6.1. ida0 output scheduling . ................. .............. .............. .............. .............. ......... 59 6.1.1. update output on-demand .. .............. .............. .............. .............. ........... 59 6.1.2. update output based on timer overflow ............. ............... ........... ......... 60 6.1.3. update output based on cnvstr edge................... ................. ............. 60 6.2. idac output mapping.......... ................. ................ ................. ................ ........... 60 7. voltage reference (c8051f330/2/4 only)........... .............. .............. .............. ......... 63 8. comparator0 ................ ................. ................ ................ ................. .............. ........... 67 9. cip-51 microcontroller .............. ................. ................ ................. ................ ........... 73 9.1. instruction set ........... ................ ................ ................. .............. .............. ........... 74 9.1.1. instruction and cpu timing .. .............. .............. .............. .............. ........... 74 9.1.2. movx instruction and program memory ... ................ ................. ............. 74 9.2. memory organization........... ................. ................ ................. ................ ........... 78 9.2.1. program memory.............. ................ ................. .............. .............. ........... 79 9.2.2. data memory........ ................. .............. .............. .............. .............. ........... 80 9.2.3. general purpose registers ................. .............. .............. .............. ........... 80 9.2.4. bit addressable lo cations.............. ................ ................. .............. ........... 80
c8051f330/1/2/3/4/5 4 rev. 1.5 9.2.5. stack ................. ................ ................. .............. .............. .............. ........... 80 9.2.6. special function registers. ................. .............. .............. .............. ........... 81 9.2.7. register descriptions ....... ................ ................. .............. .............. ........... 85 9.3. interrupt handler ................ ................ ................. ................ ................. ............. 87 9.3.1. mcu interrupt sources a nd vectors ............ ................. ................ ........... 88 9.3.2. external interrupts .......... ................ ................ ................. .............. ........... 89 9.3.3. interrupt priorities ........ ................. ................ ................. ................ ........... 89 9.3.4. interrupt latency .............. ................ ................. .............. .............. ........... 89 9.3.5. interrupt register descrip tions.............. .............. .............. .............. ......... 91 9.4. power management modes ........... .............. .............. .............. .............. ........... 96 9.4.1. idle mode............ ................ ................. .............. .............. .............. ........... 96 9.4.2. stop mode ...................... ................ ................ ................. .............. ........... 97 10. reset sources.......... ................ ................ ................. ................ ................. ............. 99 10.1.power-on reset ....... ................ ................ ................. .............. .............. ......... 100 10.2.power-fail reset/vdd monitor ............ ................ ................. ................ ......... 100 10.3.external reset .......... ................ ................ ................. .............. .............. ......... 101 10.4.missing clock detector reset ... ............... ................. .............. .............. ......... 101 10.5.comparator0 reset ............. ................. ................ ................. ................ ......... 102 10.6.pca watchdog timer reset ..... ............... ................. .............. .............. ......... 102 10.7.flash error reset ..... ................ ................ ................. .............. .............. ......... 102 10.8.software reset ......... ................ ................ ................. .............. .............. ......... 102 11. flash memory ................. ................ ................ ................. .............. .............. ......... 105 11.1.programming the flash memory ................ .............. .............. .............. ......... 105 11.1.1.flash lock and key functi ons ................ .............. ............... ........... ....... 105 11.1.2.flash erase procedure ...... ................. .............. .............. .............. ......... 105 11.1.3.flash write procedure ..... ................ ................. .............. .............. ......... 106 11.2.non-volatile data storage ... ................. ................ ................. ................ ......... 106 11.3.security options ....... ................ ................ ................. .............. .............. ......... 107 11.4.flash write and erase guidelines ............... .............. .............. .............. ......... 109 11.4.1.v dd maintenance and the v dd monitor ............ .............. .............. ......... 109 11.4.2.pswe maintenance ......... ................ ................. .............. .............. ......... 109 11.4.3.system clock ....... ................. .............. .............. .............. .............. ......... 110 12. external ram ............... ................. ................ ................ ................. .............. ......... 113 13. oscillators ................ ................ ................ ................. ................ ................. ........... 115 13.1.programmable internal hi gh-frequency (h-f) oscillator ... ................. ........... 115 13.2.programmable internal low -frequency (l-f) oscillator .... ................. ........... 117 13.2.1.calibrating the internal l- f oscillator........... ................. ................ ......... 117 13.3.external oscillator drive circuit................ ................. .............. .............. ......... 118 13.3.1.external crystal example. ................ ................. .............. .............. ......... 120 13.3.2.external rc example....... ................ ................. .............. .............. ......... 122 13.3.3.external capacitor exampl e................ .............. .............. .............. ......... 122 13.4.system clock selectio n................. .............. .............. .............. .............. ......... 123 14. port input/output............ ................ ................ ................. .............. .............. ......... 125 14.1.priority crossbar decoder ... ................. ................ ................. ................ ......... 127 14.2.port i/o initialization ........ .............. .............. .............. .............. .............. ......... 129
rev. 1.5 5 c8051f330/1/2/3/4/5 14.3.general purpose port i/o .... ................. ................ ................. ................ ......... 131 15. smbus ................. ................ ................. .............. .............. .............. .............. ......... 137 15.1.supporting documents ............. ................ ................. .............. .............. ......... 138 15.2.smbus configuration... ............... ................. .............. .............. .............. ......... 138 15.3.smbus operation ....... ................ ................. .............. .............. .............. ......... 138 15.3.1.arbitration......... ................ ................ ................. .............. .............. ......... 139 15.3.2.clock low extension........ ................ ................. .............. .............. ......... 140 15.3.3.scl low timeout.... .............. .............. .............. .............. .............. ......... 140 15.3.4.scl high (smbus free) ti meout .............. ................ ................. ........... 140 15.4.using the smbus........ ................ ................. .............. .............. .............. ......... 140 15.4.1.smbus configuration regist er................ .............. ............... ........... ....... 142 15.4.2.smb0cn control register . ................. .............. .............. .............. ......... 145 15.4.3.data register ....... ................. .............. .............. .............. .............. ......... 148 15.5.smbus transfer modes... .............. .............. .............. .............. .............. ......... 148 15.5.1.master transmitter mode .. ............... ................. .............. .............. ......... 148 15.5.2.master receiver mode .............. ................. ................ ................. ........... 150 15.5.3.slave receiver mode ....... ................ ................. .............. .............. ......... 151 15.5.4.slave transmitter mode .... ............... ................. .............. .............. ......... 152 15.6.smbus status decoding ................ .............. .............. .............. .............. ......... 152 16. uart0................ ................ ................ ................. .............. .............. .............. ......... 155 16.1.enhanced baud rate g eneration.................. .............. .............. .............. ....... 156 16.2.operational modes ....... ................. .............. .............. .............. .............. ......... 157 16.2.1.8-bit uart ........... ................. .............. .............. .............. .............. ......... 157 16.2.2.9-bit uart ........... ................. .............. .............. .............. .............. ......... 158 16.3.multiprocessor communications ... .............. .............. .............. .............. ......... 158 17. enhanced serial peripheral interface (spi0)..... .............. .............. .............. ....... 165 17.1.signal descriptions....... ................. .............. .............. .............. .............. ......... 166 17.1.1.master out, slave in (mos i)...................... ................ ................. ........... 166 17.1.2.master in, slave out (miso)............... .............. .............. .............. ......... 166 17.1.3.serial clock (sck) ........... ................ ................. .............. .............. ......... 166 17.1.4.slave select (nss) .......... ................ ................. .............. .............. ......... 166 17.2.spi0 master mode operation . ................ ................ ................. .............. ......... 167 17.3.spi0 slave mode operation ..... ................ ................. .............. .............. ......... 169 17.4.spi0 interrupt sources ........ ................. ................ ................. ................ ......... 169 17.5.serial clock timing... ................ ................ ................. .............. .............. ......... 170 17.6.spi special function registers . ............... ................. .............. .............. ......... 171 18. timers................ ................ ................ .............. .............. ............... .............. ........... 17 9 18.1.timer 0 and ti mer 1 ............... ................ ................ ................. .............. ......... 179 18.1.1.mode 0: 13-bit counter/timer ................. .............. ............... ........... ....... 179 18.1.2.mode 1: 16-bit counter/timer ................. .............. ............... ........... ....... 180 18.1.3.mode 2: 8-bit counter/tim er with auto-reload.......... ................. ........... 181 18.1.4.mode 3: two 8-bit counter /timers (timer 0 only)..... ................. ........... 182 18.2.timer 2 ............. ................ ................ ................. ................ ................. ........... 187 18.2.1.16-bit timer with auto-rel oad............... .............. .............. .............. ....... 187
c8051f330/1/2/3/4/5 6 rev. 1.5 18.2.2.8-bit timers with auto-rel oad............... .............. .............. .............. ....... 188 18.3.timer 3 ............. ................ ................ ................. ................ ................. ........... 191 18.3.1.16-bit timer with auto-rel oad............... .............. .............. .............. ....... 191 18.3.2.8-bit timers with auto-rel oad............... .............. .............. .............. ....... 192 19. programmable counter array ....... ................ ................. .............. .............. ......... 195 19.1.pca counter/timer ............. ................. ................ ................. ................ ......... 196 19.2.capture/compare modules ...... ................ ................. .............. .............. ......... 197 19.2.1.edge-triggered captur e mode................. .............. ............... ........... ....... 198 19.2.2.software timer (compare) mode................. ................. ................ ......... 199 19.2.3.high-speed output mode ..... .............. .............. .............. .............. ......... 200 19.2.4.frequency output mode ....... .............. .............. .............. .............. ......... 201 19.2.5.8-bit pulse width modulato r mode............... ................. ................ ......... 202 19.2.6.16-bit pulse width modulat or mode............. ................. ................ ......... 203 19.3.watchdog timer mode .... .............. .............. .............. .............. .............. ......... 203 19.3.1.watchdog timer operation ... .............. .............. .............. .............. ......... 204 19.3.2.watchdog timer usage ........ .............. .............. .............. .............. ......... 205 19.4.register descriptions for pca. ............... ................ ................. .............. ......... 206 20. c2 interface ................ ................ ................. ................ ................. ................ ......... 211 20.1.c2 interface registers......... ................. ................ ................. ................ ......... 211 20.2.c2 pin sharing ......... ................ ................ ................. .............. .............. ......... 213 document change list .... ................. ................ ................ ................. .............. ......... 214 contact information ......... ................. ................ ................ ................. .............. ......... 216
rev. 1.5 7 c8051f330/1/2/3/4/5 list of figures 1. system overview figure 1.1. c8051f330 block diagr am...................... ................ ................. ............. 19 figure 1.2. c8051f331 block diagr am...................... ................ ................. ............. 19 figure 1.3. c8051f332 block diagr am...................... ................ ................. ............. 20 figure 1.4. c8051f333 block diagr am...................... ................ ................. ............. 20 figure 1.5. c8051f334 block diagr am...................... ................ ................. ............. 21 figure 1.6. c8051f335 block diagr am...................... ................ ................. ............. 21 figure 1.7. comparison of pe ak mcu execution speeds ......... ................. ............. 22 figure 1.8. on-chip clock and rese t ................. .............. .............. .............. ........... 23 figure 1.9. on-board memory ma p ............... ................ ................. .............. ........... 24 figure 1.10. deve lopment/in-system debug di agram............. ............ ........... ......... 25 figure 1.11. digital cro ssbar diagram ................ .............. .............. .............. ........... 26 figure 1.12. pca block diagram.... ................ ................ ................. .............. ........... 27 figure 1.13. pca block diagram.... ................ ................ ................. .............. ........... 27 figure 1.14. 10-bit adc block diagram ....... ................ ................. ................ ........... 28 figure 1.15. compar ator0 block diagram ........ ................. .............. .............. ........... 29 figure 1.16. ida0 functional bl ock diagram ............. ................ ................. ............. 30 2. absolute maximum ratings 3. global electrical characteristics 4. pinout and package definitions figure 4.1. qfn-20 pinout diagr am (top view).......... ................. ................ ........... 37 figure 4.2. qfn-20 package drawin g................ .............. .............. .............. ........... 38 figure 4.3. qfn-20 solder paste recommendation ............... ............ ........... ......... 39 figure 4.4. typical qfn-20 landi ng diagram ............. ................. ................ ........... 40 figure 4.5. pdip-20 pi nout diagram (top view) ... ............. .............. .............. ......... 41 figure 4.6. pdip-20 package draw ing ............... .............. .............. .............. ........... 42 5. 10-bit adc (adc0, c8051f330/2/4 only) figure 5.1. adc0 functional bl ock diagram ............. ................ ................. ............. 43 figure 5.2. typical temperatur e sensor transfer function .... ............ ........... ......... 45 figure 5.3. 10-bit adc track and conversion example timing ................. ............. 47 figure 5.4. adc0 equiva lent input circuits ........ .............. .............. .............. ........... 48 figure 5.5. adc window compare example: right-jus tified single-ended data... 55 figure 5.6. adc window co mpare example: left-justifi ed single-ended data ..... 55 figure 5.7. adc window co mpare example: right-justifi ed differential data ....... 56 figure 5.8. adc window com pare example: left-justified differential data ......... 56 6. 10-bit current mode dac (ida0, c8051f330 only) figure 6.1. ida0 functional blo ck diagram............... ................ ................. ............. 59 figure 6.2. ida0 data word m apping.............. ................. .............. .............. ........... 60 7. voltage reference (c8051f330/2/4 only) figure 7.1. voltage reference functional block diagram ....... ............ ........... ......... 63 8. comparator0 figure 8.1. comparator0 functi onal block diagram.... ................. ................ ........... 67 figure 8.2. comparator hysteres is plot........... ................. .............. .............. ........... 68
c8051f330/1/2/3/4/5 8 rev. 1.5 9. cip-51 microcontroller figure 9.1. cip-51 block diagram .. ............... ................ ................. .............. ........... 73 figure 9.2. memory map........... ................ ................. ................ ................. ............. 79 10. reset sources figure 10.1. rese t sources.............. ................ ................. .............. .............. ........... 99 figure 10.2. power-on and vdd monitor reset timing ....... ............... ........... ....... 100 11. flash memory figure 11.1. flash program memo ry map.................. ................ ................. ........... 107 12. external ram 13. oscillators figure 13.1. oscillator diagram............... .............. .............. .............. .............. ....... 115 figure 13.2. external 32.768 khz quartz crystal oscillat or connection diagram . 121 14. port input/output figure 14.1. port i/o functional block diagram ................ .............. .............. ......... 125 figure 14.2. port i/o ce ll block diagram ............ .............. .............. .............. ......... 126 figure 14.3. crossbar priority decoder with no pins sk ipped ............... ................ 127 figure 14.4. crossbar priority decoder with crystal pins skipped .......... .............. 128 15. smbus figure 15.1. smbus block diagram ............. ................ ................. ................ ......... 137 figure 15.2. typical smbu s configuration .......... .............. .............. .............. ......... 138 figure 15.3. smbus transac tion ............. .............. .............. .............. .............. ....... 139 figure 15.4. typical sm bus scl generation........ .............. .............. .............. ....... 143 figure 15.5. typical ma ster transmitter sequence............. .............. .............. ....... 149 figure 15.6. typical ma ster receiver sequence................. .............. .............. ....... 150 figure 15.7. typical slave rece iver sequence............ ................. ................ ......... 151 figure 15.8. typical slave trans mitter sequence........ ................. ................ ......... 152 16. uart0 figure 16.1. uart0 block diagram ............. ................ ................. ................ ......... 155 figure 16.2. uart0 baud rate logic ............ ................ ................. .............. ......... 156 figure 16.3. uart interconnect di agram ............. .............. .............. .............. ....... 157 figure 16.4. 8-bit uart timing diagram............ .............. .............. .............. ......... 157 figure 16.5. 9-bit uart timing diagram............ .............. .............. .............. ......... 158 figure 16.6. uart multi-proc essor mode interconne ct diagram .......... ................ 159 17. enhanced serial peripheral interface (spi0) figure 17.1. spi bl ock diagram ............ .............. .............. .............. .............. ......... 165 figure 17.2. multiple -master mode connection diagram ...... ............... ........... ....... 168 figure 17.3. 3-wi re single master a nd 3-wire single slav e mode connection diagram 168 figure 17.4. 4-wire single master mode and 4-wire slave m ode connection diagram 168 figure 17.5. master mode data/ clock timing .............. ................. ................ ......... 170 figure 17.6. slave mode data/clock timing (ckpha = 0) ... ............... ........... ....... 171 figure 17.7. slave mode data/clock timing (ckpha = 1) ... ............... ........... ....... 171 figure 17.8. spi ma ster timing (ckpha = 0).. ................. .............. .............. ......... 175 figure 17.9. spi ma ster timing (ckpha = 1).. ................. .............. .............. ......... 175
rev. 1.5 9 c8051f330/1/2/3/4/5 figure 17.10. spi slave timing (c kpha = 0).............. ................. ................ ......... 176 figure 17.11. spi slave timing (c kpha = 1).............. ................. ................ ......... 176 18. timers figure 18.1. t0 mode 0 bl ock diagram............... .............. .............. .............. ......... 180 figure 18.2. t0 mode 2 bl ock diagram............... .............. .............. .............. ......... 181 figure 18.3. t0 mode 3 bl ock diagram............... .............. .............. .............. ......... 182 figure 18.4. timer 2 16- bit mode block diagram .. ............. .............. .............. ....... 187 figure 18.5. timer 2 8- bit mode block diagram .. ................. ............... ........... ....... 188 figure 18.6. timer 3 16- bit mode block diagram .. ............. .............. .............. ....... 191 figure 18.7. timer 3 8- bit mode block diagram .. ................. ............... ........... ....... 192 19. programmable counter array figure 19.1. pca block diagram.... ................ ................ ................. .............. ......... 195 figure 19.2. pca counter /timer block diagram.... ............. .............. .............. ....... 196 figure 19.3. pca interrupt blo ck diagram ................. ................ ................. ........... 197 figure 19.4. pca captur e mode diagram............. .............. .............. .............. ....... 198 figure 19.5. pca software time r mode diagram ........ ................. ................ ......... 199 figure 19.6. pca high- speed output mode diagram........... ............... ........... ....... 200 figure 19.7. pca fr equency output mode ......... .............. .............. .............. ......... 201 figure 19.8. pca 8-bit pwm mode diagram .......... .............. ............... ........... ....... 202 figure 19.9. pca 16-bit pwm mode ................ ................. .............. .............. ......... 203 figure 19.10. pca module 2 with watchdog ti mer enabled ..... ................. ........... 204 20. c2 interface figure 20.1. typical c2 pin sharing.......... ................. ................ ................. ........... 213
c8051f330/1/2/3/4/5 10 rev. 1.5
rev. 1.5 11 c8051f330/1/2/3/4/5 list of tables 1. system overview table 1.1. product selection guide . ............... ................ ................. .............. .......... 18 2. absolute maximum ratings table 2.1. absolute maximum rati ngs .................... .............. ............... ........... ........ 31 3. global electrical characteristics table 3.1. global elec trical characteristics .................. ................. ................ .......... 32 table 3.2. index to electrical characteristics tables ............. ............... ........... ........ 34 4. pinout and package definitions table 4.1. pin definitions for the c8051f330/1/2/3/4/5............ ............ ........... ........ 35 table 4.2. qfn-20 package dimensio ns ................ .............. ............... ........... ........ 38 table 4.3. pdip-20 package dime nsions ........... .............. .............. .............. .......... 42 5. 10-bit adc (adc0 , c8051f330/2/4 only) table 5.1. adc0 electrical char acteristics....... ................. .............. .............. .......... 57 6. 10-bit current mode dac (ida0, c8051f330 only) table 6.1. idac electric al characteristics........ ................. .............. .............. .......... 62 7. voltage reference (c8051f330/2/4 only) table 7.1. voltage reference el ectrical characteristics........ ............... ........... ........ 65 8. comparator0 table 8.1. comparator electrical characteristics .... .............. ............... ........... ........ 72 9. cip-51 microcontroller table 9.1. cip-51 instruction se t summary ............... ................ ................. ............ 75 table 9.2. special function regi ster (sfr) memory map ....... ............ ........... ........ 81 table 9.3. special function regist ers ................. .............. .............. .............. .......... 82 table 9.4. interrupt summary ...... ................. ................ ................. ................ .......... 90 10. reset sources table 10.1. reset electrical char acteristics ............ ................. ................ ............. 104 11. flash memory table 11.1. flash electrical char acteristics........... .............. .............. ............ ........ 106 table 11.2. flash security summar y................ .............. ............... .............. .......... 108 12. external ram 13. oscillators table 13.1. internal osc illator electrical characteristics ............... .............. .......... 124 14. port input/output table 14.1. port i/o dc electric al characteristics... ................. ................ ............. 136 15. smbus table 15.1. smbus clock source selection ............... ................ ................. .......... 142 table 15.2. minimum sda setup and hold times ....... ................. .............. .......... 143 table 15.3. sources for hardware changes to smb0cn ................. ............ ........ 147 table 15.4. smbus status decoding................ .............. ............... .............. .......... 153 16. uart0 table 16.1. timer settings for standard baud rates using the internal 24.5 mhz os- cillator .............. ................ .............. .............. ............... .............. .......... 162
c8051f330/1/2/3/4/5 12 rev. 1.5 table 16.2. timer settings for standard baud rates using an external 25.0 mhz os- cillator .............. ................ ................. .............. .............. .............. ........ 162 table 16.3. timer settings for standard baud rates using an external 22.1184 mhz oscillator............ ................. .............. .............. .............. .............. ........ 163 table 16.4. timer settings for standard baud rates usin g an external 18.432 mhz oscillator............ ................. .............. .............. .............. .............. ........ 163 table 16.5. timer settings for standard baud rates using an external 11.0592 mhz oscillator............ ................. .............. .............. .............. .............. ........ 164 table 16.6. timer settings for standard baud rates usin g an external 3.6864 mhz oscillator............ ................. .............. .............. .............. .............. ........ 164 17. enhanced serial peripheral interface (spi0) table 17.1. spi slave timing para meters ............ .............. .............. .............. ...... 177 18. timers 19. programmable counter array table 19.1. pca timebase input op tions ............. .............. .............. .............. ...... 196 table 19.2. pca0cpm register settings for pca captur e/compare modules .... 197 table 19.3. watchdog timer timeout intervals1.......... ................. ................ ........ 206 20. c2 interface
rev. 1.5 13 c8051f330/1/2/3/4/5 list of registers sfr definition 5.1. amx0p: amux0 positive channel select . . . . . . . . . . . . . . . . . . . 49 sfr definition 5.2. amx0n: amux 0 negative channel select . . . . . . . . . . . . . . . . . . 50 sfr definition 5.3. adc0cf: adc0 c onfiguration . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 sfr definition 5.4. adc0h: adc0 data word msb . . . . . . . . . . . . . . . . . . . . . . . . . . 51 sfr definition 5.5. adc0l: adc0 data word lsb . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 sfr definition 5.6. adc0cn: adc0 control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 sfr definition 5.7. adc0gth: a dc0 greater-than data high byte . . . . . . . . . . . . . 53 sfr definition 5.8. adc0gtl: ad c0 greater-than data low byte . . . . . . . . . . . . . . 53 sfr definition 5.9. adc0lth: ad c0 less-than data high byte . . . . . . . . . . . . . . . . 54 sfr definition 5.10. adc0ltl: ad c0 less-than data low byte . . . . . . . . . . . . . . . . 54 sfr definition 6.1. ida0cn: ida0 control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 sfr definition 6.2. ida0h: ida0 da ta word msb . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 sfr definition 6.3. ida0l: ida0 data word lsb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 sfr definition 7.1. ref0cn: reference control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 sfr definition 8.1. cpt0cn : comparator0 control . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 sfr definition 8.2. cpt0mx : comparator0 mux select ion . . . . . . . . . . . . . . . . . . . . 70 sfr definition 8.3. cpt0md : comparator0 mode selection . . . . . . . . . . . . . . . . . . . . 71 sfr definition 9.1. dpl: da ta pointer low byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 sfr definition 9.2. dph: data pointer high byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 sfr definition 9.3. sp: stack pointer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 sfr definition 9.4. psw: pr ogram status word . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 sfr definition 9.5. acc: accu mulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 sfr definition 9.6. b: b register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 sfr definition 9.7. ie: interrupt enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 sfr definition 9.8. ip: interr upt priority . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 sfr definition 9.9. eie1: extended interrupt enable 1 . . . . . . . . . . . . . . . . . . . . . . . . 93 sfr definition 9.10. eip1: extended inte rrupt priority 1 . . . . . . . . . . . . . . . . . . . . . . . 94 sfr definition 9.11. it01cf: int0/int 1 configuration . . . . . . . . . . . . . . . . . . . . . . . . 95 sfr definition 9.12. pc on: power control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 sfr definition 10.1. vdm0cn : vdd monitor control . . . . . . . . . . . . . . . . . . . . . . . . 101 sfr definition 10.2. rstsrc: reset source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 sfr definition 11.1. psctl: program store r/w control . . . . . . . . . . . . . . . . . . . . . 110 sfr definition 11.2. flkey: flash lock and key . . . . . . . . . . . . . . . . . . . . . . . . . . . 111 sfr definition 11.3. flscl: flash scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111 sfr definition 12.1. emi0 cn: external memory interface cont rol . . . . . . . . . . . . . . 113 sfr definition 13.1. oscicl: intern al h-f oscillator calibration . . . . . . . . . . . . . . . 116 sfr definition 13.2. oscicn: inter nal h-f oscillator control . . . . . . . . . . . . . . . . . . 116 sfr definition 13.3. osclcn: inter nal l-f oscillator control . . . . . . . . . . . . . . . . . . 117 sfr definition 13.4. oscxcn: external oscillator c ontrol . . . . . . . . . . . . . . . . . . . . 119 sfr definition 13.5. clksel: clock select . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123 sfr definition 14.1. xbr0: port i/o crossbar regist er 0 . . . . . . . . . . . . . . . . . . . . . 130 sfr definition 14.2. xbr1: port i/o crossbar regist er 1 . . . . . . . . . . . . . . . . . . . . . 131 sfr definition 14.3. p0: port0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132
c8051f330/1/2/3/4/5 14 rev. 1.5 sfr definition 14.4. p0mdin : port0 input mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132 sfr definition 14.5. p0mdout: port 0 output mode . . . . . . . . . . . . . . . . . . . . . . . . . 133 sfr definition 14.6. p0ski p: port0 skip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133 sfr definition 14.7. p1: port1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133 sfr definition 14.8. p1mdin : port1 input mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134 sfr definition 14.9. p1mdout: port 1 output mode . . . . . . . . . . . . . . . . . . . . . . . . . 134 sfr definition 14.10. p1 skip: port1 skip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134 sfr definition 14.11. p2: port2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135 sfr definition 14.12. p2mdout: port 2 output mode . . . . . . . . . . . . . . . . . . . . . . . . 135 sfr definition 15.1. smb0cf: smbu s clock/configuration . . . . . . . . . . . . . . . . . . . 144 sfr definition 15.2. smb0cn : smbus control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146 sfr definition 15.3. smb0dat: smbus data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148 sfr definition 16.1. scon0: serial port 0 control . . . . . . . . . . . . . . . . . . . . . . . . . . 160 sfr definition 16.2. sbuf0: serial (uart0) port data buffer . . . . . . . . . . . . . . . . . 161 sfr definition 17.1. spi0cf g: spi0 configuration . . . . . . . . . . . . . . . . . . . . . . . . . . 172 sfr definition 17.2. spi0cn: spi0 control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173 sfr definition 17.3. spi0ck r: spi0 clock rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174 sfr definition 17.4. spi0dat: spi0 data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174 sfr definition 18.1. tcon: timer cont rol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183 sfr definition 18.2. tmod: ti mer mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184 sfr definition 18.3. ckcon: clock control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185 sfr definition 18.4. tl0: timer 0 low byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186 sfr definition 18.5. tl1: timer 1 low byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186 sfr definition 18.6. th0: timer 0 hi gh byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186 sfr definition 18.7. th1: timer 1 hi gh byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186 sfr definition 18.8. tmr2cn: timer 2 control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189 sfr definition 18.9. tmr2rll: ti mer 2 reload register low byte . . . . . . . . . . . . . 190 sfr definition 18.10. tmr2 rlh: timer 2 reload re gister high byte . . . . . . . . . . . 190 sfr definition 18.11. tmr2l: timer 2 low byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190 sfr definition 18.12. tmr2h timer 2 high byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190 sfr definition 18.13. tmr3cn: timer 3 control . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193 sfr definition 18.14. tmr3 rll: timer 3 reload regi ster low byte . . . . . . . . . . . . 194 sfr definition 18.15. tmr3 rlh: timer 3 reload re gister high byte . . . . . . . . . . . 194 sfr definition 18.16. tmr3l: timer 3 low byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194 sfr definition 18.17. tmr3h timer 3 high byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194 sfr definition 19.1. pca0cn: pca control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207 sfr definition 19.2. pca0md: pca mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208 sfr definition 19.3. pc a0cpmn: pca capture/compare mode . . . . . . . . . . . . . . . 209 sfr definition 19.4. pca0l: pca counter/timer low byte . . . . . . . . . . . . . . . . . . . 210 sfr definition 19.5. pca0h: pca counter/timer high byte . . . . . . . . . . . . . . . . . . . 210 sfr definition 19.6. pca0cpln: pca capture module low byte . . . . . . . . . . . . . . . 210 sfr definition 19.7. pca0cphn: pca capture module high byte . . . . . . . . . . . . . . 210 c2 register definition 20.1. c2add: c2 address . . . . . . . . . . . . . . . . . . . . . . . . . . . 211 c2 register definition 20.2. device id: c2 device id . . . . . . . . . . . . . . . . . . . . . . . . 211 c2 register definition 20.3. revid: c2 revision id . . . . . . . . . . . . . . . . . . . . . . . . . 212
rev. 1.5 15 c8051f330/1/2/3/4/5 c2 register definition 20.4. fp ctl: c2 flash programming cont rol . . . . . . . . . . . . 212 c2 register definition 20.5. fp dat: c2 flash programming data . . . . . . . . . . . . . . 212
c8051f330/1/2/3/4/5 16 rev. 1.5
rev. 1.5 17 c8051f330/1/2/3/4/5 1. system overview c8051f330/1/2/3/4/5 devices are fully integrated mixed-signal system-on-a-chip mcus. highlighted fea - tures are listed be low. refer to ta b l e 1.1 for specific product feature selection. ? high-speed pipelined 8051-compatible microcontroller core (up to 25 mips) ? in-system, full-speed, non-intrusive debug interface (on-chip) ? true 10-bit 200 ksps 16-channel single-ended/diffe rential adc with analog multiplexer ? 10-bit current output dac ? precision programmable 25 mhz internal oscillator ? up to 8 kb of on-chip flash memory?512 bytes are reserved ? 768 bytes of on-chip ram ? smbus/i2c, enhanced uart, and enhanced spi serial interfaces implemented in hardware ? four general-purpose 16-bit timers ? programmable counter/timer array (pca) with three capture/compare modules and watchdog timer function ? on-chip power-on reset, v dd monitor, and temperature sensor ? on-chip voltage comparator ? 17 port i/o (5 v tolerant) with on-chip power-on reset, v dd monitor, watchdog timer, and clock oscillator, the c8051f330/1/2/3/4/5 devices are truly stand-alone s ystem-on-a-chip solutions. the flash memory can be reprogrammed even in-circuit, providing non-volatile data storage, and also allowing field upgrades of the 8051 firmware. user software has complete control of all peripherals, and may individually shut down any or all peripherals for power savings. the on-chip silicon labs 2- wire (c2) development interface allo ws non-intrusive (uses no on-chip resources), full speed, in-circuit debugging using the production mcu installed in the final application. this debug logic supports inspection and modification of memory and registers, setting breakpoints, single stepping, run and halt commands. all analog and digita l peripherals are fully functional while debugging using c2. the two c2 interface pins can be shared with user functions , allowing in-system debugging with - out occupying package pins. each device is specified for 2.7 to 3.6 v operation over the industrial temperature range (?40 to +85 c). the port i/o and rst pins are tolerant of input signals up to 5 v. the c8051f330/1/2/3/4/5 are available in 20-pin qfn packages (also referred to as mlp or mlf packages) and the c8051f330 is available in a 20- pin pdip package. lead-free (rohs complia nt) packages are also available. see table 1.1 for ordering part numbers. block diagrams are included in figure 1.1 , figure 1.2 , figure 1.3 , figure 1.4 , figure 1.5 , and figure 1.6 .
c8051f330/1/2/3/4/5 18 rev. 1.5 table 1.1. product selection guide ordering part number mips (peak) flash memory (kb) ram (bytes) calibrated internal 24.5 mhz oscillator internal 80 khz oscillator smbus/i 2 c enhanced spi uart timers (16-bit) programmable counter array digital port i/os 10-bit 200ksps adc 10-bit current output dac internal voltage reference temperature sensor analog comparator lead-free (rohs compliant) package c8051f330 25 8 768 3 3 3 3 3 4 3 17 3 3 3 3 3 ? qfn-20 c8051f330-gm 25 8 768 3 3 3 3 3 4 3 17 3 3 3 3 3 3 qfn-20 c8051f330d 25 8 768 3 3 3 3 3 4 3 17 3 3 3 3 3 ? pdip-20 c8051f330-gp 25 8 768 3 3 3 3 3 4 3 17 3 3 3 3 3 3 pdip-20 c8051f331 25 8 768 3 3 3 3 3 4 3 17 ? ? ? ? 3 ? qfn-20 c8051f331-gm 25 8 768 3 3 3 3 3 4 3 17 ? ? ? ? 3 3 qfn-20 c8051f332-gm 25 4 768 3 3 3 3 3 4 3 17 3 ? 3 3 3 3 qfn-20 c8051f333-gm 25 4 768 3 3 3 3 3 4 3 17 ? ? ? ? 3 3 qfn-20 C8051F334-GM 25 2 768 3 3 3 3 3 4 3 17 3 ? 3 3 3 3 qfn-20 c8051f335-gm 25 2 768 3 3 3 3 3 4 3 17 ? ? ? ? 3 3 qfn-20
rev. 1.5 19 c8051f330/1/2/3/4/5 figure 1.1. c8051f330 block diagram figure 1.2. c8051f331 block diagram port 0 latch uart 8 kb flash 256 byte sram por sfr bus 8 0 5 1 c o r e timer 0, 1, 2, 3 3-chnl pca/ wdt 10-bit 200ksps adc a m u x ain0-ain15 p 0 d r v vdd x b a r reset xtal1 xtal2 external oscillator circuit system clock 24.5 mhz (2%) internal oscillator analog/digital power debug hw vref smbus c2d c2d cp0 + - temp p0.0/vref p0.1/ida0 p0.2/xtal1 p0.3/xtal2 p0.4/tx p0.5/rx p0.6/cnvstr p0.7 vdd gnd rst/c2ck brown- out p 1 d r v p1.0 p1.1 p1.2 p1.3 p1.4 p1.5 p1.6 p1.7 spi port 1 latch 512 byte xram p2.0/c2d port 2 latch vref 80 khz internal oscillator 10-bit dac port 0 latch uart 8 kb flash 256 byte sram por sfr bus 8 0 5 1 c o r e timer 0, 1, 2, 3 3-chnl pca/ wdt p 0 d r v x b a r reset xtal1 xtal2 external oscillator circuit system clock 24.5 mhz (2%) internal oscillator analog/digital power debug hw smbus c2d c2d cp0 + - p0.0 p0.1 p0.2/xtal1 p0.3/xtal2 p0.4/tx p0.5/rx p0.6 p0.7 vdd gnd rst/c2ck brown- out p 1 d r v p1.0 p1.1 p1.2 p1.3 p1.4 p1.5 p1.6 p1.7 spi port 1 latch 512 byte xram p2.0/c2d port 2 latch 80 khz internal oscillator
c8051f330/1/2/3/4/5 20 rev. 1.5 figure 1.3. c8051f332 block diagram figure 1.4. c8051f333 block diagram port 0 latch uart 4 kb flash 256 byte sram por sfr bus 8 0 5 1 c o r e timer 0, 1, 2, 3 3-chnl pca/ wdt 10-bit 200 ksps adc a m u x ain0-ain15 p 0 d r v vdd x b a r reset xtal1 xtal2 external oscillator circuit system clock 24.5 mhz (2%) internal oscillator analog/digital power debug hw vref smbus c2d c2d cp0 + - temp p0.0/vref p0.1 p0.2/xtal1 p0.3/xtal2 p0.4/tx p0.5/rx p0.6/cnvst p0.7 vdd gnd /rst/c2ck brown- out p 1 d r v p1.0 p1.1 p1.2 p1.3 p1.4 p1.5 p1.6 p1.7 spi port 1 latch 512 byte xram p2.0/c2d port 2 latch vref 80 khz internal oscillator port 0 latch uart 4 kb flash 256 byte sram por sfr bus 8 0 5 1 c o r e timer 0, 1, 2, 3 3-chnl pca/ wdt p 0 d r v x b a r reset xtal1 xtal2 external oscillator circuit system clock 24.5 mhz (2%) internal oscillator analog/digital power debug hw smbus c2d c2d cp0 + - p0.0 p0.1 p0.2/xtal1 p0.3/xtal2 p0.4/tx p0.5/rx p0.6 p0.7 vdd gnd /rst/c2ck brown- out p 1 d r v p1.0 p1.1 p1.2 p1.3 p1.4 p1.5 p1.6 p1.7 spi port 1 latch 512 byte xram p2.0/c2d port 2 latch 80 khz internal oscillator
rev. 1.5 21 c8051f330/1/2/3/4/5 figure 1.5. c8051f334 block diagram figure 1.6. c8051f335 block diagram port 0 latch uart 2 kb flash 256 byte sram por sfr bus 8 0 5 1 c o r e timer 0, 1, 2, 3 3-chnl pca/ wdt 10-bit 200 ksps adc a m u x ain0-ain15 p 0 d r v vdd x b a r reset xtal1 xtal2 external oscillator circuit system clock 24.5 mhz (2%) internal oscillator analog/digital power debug hw vref smbus c2d c2d cp0 + - temp p0.0/vref p0.1 p0.2/xtal1 p0.3/xtal2 p0.4/tx p0.5/rx p0.6/cnvst p0.7 vdd gnd /rst/c2ck brown- out p 1 d r v p1.0 p1.1 p1.2 p1.3 p1.4 p1.5 p1.6 p1.7 spi port 1 latch 512 byte xram p2.0/c2d port 2 latch vref 80 khz internal oscillator port 0 latch uart 2 kb flash 256 byte sram por sfr bus 8 0 5 1 c o r e timer 0, 1, 2, 3 3-chnl pca/ wdt p 0 d r v x b a r reset xtal1 xtal2 external oscillator circuit system clock 24.5 mhz (2%) internal oscillator analog/digital power debug hw smbus c2d c2d cp0 + - p0.0 p0.1 p0.2/xtal1 p0.3/xtal2 p0.4/tx p0.5/rx p0.6 p0.7 vdd gnd /rst/c2ck brown- out p 1 d r v p1.0 p1.1 p1.2 p1.3 p1.4 p1.5 p1.6 p1.7 spi port 1 latch 512 byte xram p2.0/c2d port 2 latch 80 khz internal oscillator
c8051f330/1/2/3/4/5 22 rev. 1.5 1.1. cip-51? microcontroller core 1.1.1. fully 8051 compatible the c8051f330/1/2/3/4/5 fam ily utilizes silicon labs' proprietary ci p-51 microcontr oller core. the cip-51 is fully compatible with the mcs- 51? instruction set; standard 803x/805x assemblers and compilers can be used to develop software. the cip-51 core offers all the peripherals included with a standard 8052, including four 16-bit counter/timers, a full-duplex uart with extended baud rate configuration, an enhanced spi port, 768 bytes of internal ram, 128 byte special function register (sfr) address space, and 17 i/o pins. 1.1.2. improved throughput the cip-51 employs a pipelined architecture that grea tly increases its instruction throughput over the stan - dard 8051 architecture. in a standar d 8051, all instructions except for mul and div take 12 or 24 system clock cycles to execute with a ma ximum system clock of 12-to-24 mhz. by contrast, the cip-51 core exe - cutes 70% of its instructions in one or two system clock cycles, with only four inst ructions taking more than four system clock cycles. the cip-51 has a total of 109 instructions. the table below shows the total number of instructions that require each execution time. with the cip-51's maximum system clock at 25 mhz, it has a peak throughput of 25 mips. figure 1.7 shows a comparison of peak throughputs for variou s 8-bit microcontroller cores with their maximum sys - tem clocks. figure 1.7. comparison of peak mcu execution speeds clocks to execute 1 2 2/3 3 3/4 4 4/5 5 8 number of instructions 26 50 5 14 7 3 1 2 1 5 10 15 20 aduc812 8051 (16 mhz clk) philips 80c51 (33 mhz clk) microchip pic17c75x (33 mhz clk) silicon labs cip-51 (25 mhz clk) mips 25
rev. 1.5 23 c8051f330/1/2/3/4/5 1.1.3. additional features the c8051f330/1/2/3/4/5 soc family includes several key enhancements to the cip-51 core and periph - erals to improve performance and ea se of use in end applications. the extended interrupt handler provides 14 interrupt sources into the cip-51 (as opposed to 7 for the stan - dard 8051), allowing numerous analog and digital peripherals to interrupt the controller. an interrupt driven system requires less interv ention by the mcu, giving it more effe ctive throughput. the extra interrupt sources are very useful when build ing multi-tasking, real-time systems. eight reset sources are available: power-on reset circuitry (por), an on-chip v dd monitor (forces reset when power supply voltage drops below v rst as given in table 10.1 on page 104 ), a watchdog timer, a missing clock detector, a voltage level detection from comparator0, a forced software reset, an external reset pin, and an illegal flash access protection circui t. each reset source except for the por, reset input pin, or flash error may be disabled by the user in software. the wdt may be permanently enabled in soft - ware after a power-on rese t during mcu initialization. the internal osc illator factory calibrated to 24.5 mhz 2%. this internal oscillato r period may be user pro - grammed in ~0.5% increments. an a dditional low-frequency oscillator is also available which facilitates low-power operation. an exte rnal oscillator drive circuit is included , allowing an extern al crystal, ceramic resonator, capacitor, rc, or cmos clock source to generate the system clock. if desired, the system clock source may be switched on-the-fly be tween both internal and external os cillator circuits. an external oscil - lator can also be extremely useful in low power applic ations, allowing the mcu to run from a slow (power saving) source, while periodically switching to the fast (up to 25 mhz) internal os cillator as needed. figure 1.8. on-chi p clock and reset pca wdt missing clock detector (one- shot) (software reset) system reset reset funnel px.x px.x en swrsf internal oscillator system clock cip-51 microcontroller core extended interrupt handler clock select en wdt enable mcd enable xtal1 xtal2 external oscillator drive errant flash operation /rst (wired-or) power on reset '0' + - comparator 0 c0rsef vdd + - supply monitor enable low frequency oscillator
c8051f330/1/2/3/4/5 24 rev. 1.5 1.2. on-chip memory the cip-51 has a standard 8051 program and data addr ess configuration. it in cludes 256 bytes of data ram, with the upper 128 bytes dual-mapped. indirect addressing accesses the upper 128 bytes of general purpose ram, and direct addressing accesses the 128 byte sfr addre ss space. the lower 128 bytes of ram are accessible via direct and indirect addressing. the first 32 bytes are addressable as four banks of general purpose registers, and the next 16 byte s can be byte addressable or bit addressable. program memory c onsists of 2/4/8 kb of flash. this memory may be reprogrammed in-system in 512 byte sectors, and requires no special off-chip programming voltage. see figure 1.9 for the mcu system mem - ory map. figure 1.9. on-board memory map c8051f330/1 program/data memory (flash) (direct and indirect addressing) 0x00 0x7f upper 128 ram (indirect addressing only) 0x80 0xff special function register's (direct addressing only) data memory (ram) general purpose registers 0x1f 0x20 0x2f bit addressable lower 128 ram (direct and indirect addressing) 0x30 internal data address space external data address space xram - 512 bytes (accessable using movx instruction) 0x0000 0x01ff same 512 bytes as from 0x0000 to 0x01ff, wrapped on 512-byte boundaries 0x0200 0xffff 8 k flash (in-system programmable in 512 byte sectors) 0x0000 reserved 0x1e00 0x1dff c8051f332/3 program/data memory (flash) 4 k flash (in-system programmable in 512 byte sectors) 0x0000 reserved 0x1000 0x0fff c8051f334/5 program/data memory (flash) 2 k flash (in-system programmable in 512 byte sectors) 0x0000 reserved 0x800 0x7ff
rev. 1.5 25 c8051f330/1/2/3/4/5 1.3. on-chip debug circuitry the c8051f330/1/2/3/4/ 5 devices include on-chip s ilicon labs 2-wire (c2) debug circuitry that provides non-intrusive, full speed, in-circuit debugging of the production part installed in the end application. silicon labs' debugging syst em supports inspection and modificati on of memory and registers, break - points, and single stepping. no additional target ram, program memory, timers, or communications chan - nels are required. all the digital and analog periphera ls are functional and work correctly while debugging. all the peripherals (except for the adc and smbus) are stalled when the mcu is halted, during single stepping, or at a breakpoint in order to keep them synchronized. the c8051f330dk development kit provides all the har dware and software necessary to develop applica - tion code and perform in-circuit debugging with the c8051f330/1/2/3/4/5 mcus. the kit includes software with a developer's studio and debugger, an integrated 8051 assembler, and a debug adapter. it also has a target application board with the associated mcu insta lled and prototyping area, plus the required cables, and wall-mount power supply. the development kit requires a pc running windows98se or later. the silicon labs ide interface is a vastly superior developing and debu gging configuratio n, compared to standard mcu emulators that use on-board "ice chips" and require the mcu in the application board to be socketed. silicon labs' debug para digm increases ease of use and preserves the performance of the precision analog peripherals. figure 1.10. development/ in-system debug diagram target pcb debug adapter vdd gnd c2 (x2), vdd, gnd windows 98se or later silicon labs integrated development environment c8051f330
c8051f330/1/2/3/4/5 26 rev. 1.5 1.4. programmable digital i/o and crossbar c8051f330/1/2/3/4/5 devices include 17 i/o pins (two byte-wide ports and one 1-bit-wide port). the c8051f330/1/2/3/4/5 ports behave like typical 8051 ports with a few enhancements. each port pin may be configured as an analog input or a digital i/o pin. pi ns selected as digital i/os may additionally be config - ured for push-pull or open-drain output. the ?weak pullups? that are fixed on typical 8051 devices may be globally disabled, providing power savings capabilities. the digital crossbar allows mapping of internal digital system resources to port i/o pins. (see figure 1.11 .) on-chip counter/timers, serial buses, hw inte rrupts, comparator output, and other digital sig - nals in the controller can be configured to appear on the port i/o pins specifi ed in the crossbar control registers. this allows the user to select the exact mix of general purpose port i/o and digital resources needed for the particular application. figure 1.11. digital crossbar diagram 1.5. serial ports the c8051f330/1/2/3/4/5 family includes an smbus/i 2 c interface, a full-duplex uart with enhanced baud rate configuration, and an enhanced spi interface. each of the serial buses is fully implemented in hardware and makes extensive use of the cip-51's inte rrupts, thus requiring very little cpu intervention. xbr0, xbr1, pnskip registers digital crossbar priority decoder 2 p0 i/o cells p0.0 p0.7 8 pnmdout, pnmdin registers uart (internal digital signals) highest priority lowest priority sysclk 2 smbus t0, t1 2 4 pca 4 spi cp0 outputs 2 p1 i/o cells p1.0 p1.7 8 (port latches) p0 (p0.0-p0.7) (p1.0-p1.7) 8 8 p1
rev. 1.5 27 c8051f330/1/2/3/4/5 1.6. programmable counter array an on-chip programmable counter/timer array (pca) is included in addition to the four 16-bit general pur - pose counter/timers. the pca consists of a dedicated 16-bit counter/timer time base with three program - mable capture/compare modules. the pca clock is de rived from one of six so urces: the system clock divided by 12, the system clock divided by 4, timer 0 overflows, an external cl ock input (eci), the system clock, or the external osc illator clock source divided by 8. the extern al clock source selection is useful for real-time clock functi onality, where the pca is clocked by an exte rnal source while the internal oscillator drives the system clock. each capture/compare module can be configured to operate in one of six modes: edge-triggered capture, software timer, high speed output, 8- or 16-bit pulse width modulator, or frequency output. additionally, capture/compare mo dule 2 offers watchdog timer (wdt) capabilit ies. following a system reset, module 2 is configured and enabled in wdt mode. the pca capture/compare module i/o and external clock input may be routed to port i/o via the digital crossbar. figure 1.13. pca block diagram capture/compare module 1 capture/compare module 0 capture/compare module 2 / wdt cex1 eci crossbar cex2 cex0 port i/o 16-bit counter/timer pca clock mux sysclk/12 sysclk/4 timer 0 overflow eci sysclk external clock/8
c8051f330/1/2/3/4/5 28 rev. 1.5 1.7. 10-bit analog to digital converter the c8051f330/2/4 devices include an on-chip 10-bit sar adc with a 16-channel differential input multi - plexer. with a maximum throughput of 200 ksps, the adc offers true 10-bit linearity with an inl and dnl of 1 lsb. the adc system includes a configurable analo g multiplexer that selects both positive and nega - tive adc inputs. ports0-1 are available as an adc inputs; additionally, the on-chip temperature sensor output and the power supply voltage (v dd ) are available as adc inputs. user firmware may shut down the adc to save power. conversions can be started in six ways: a software comma nd, an overflow of timer 0, 1, 2, or 3, or an external convert start signal. this flexibility allows the start of conver sion to be triggered by software events, a periodic signal (timer overflows), or extern al hw signals. conversion completions are indicated by a status bit and an interrupt (if enabled). the resu lting 10-bit data word is latched into the adc data sfrs upon completion of a conversion. window compare registers for the adc data can be conf igured to interrupt the co ntroller when adc data is either within or outside of a specified range. the adc can monitor a key voltage continuously in back - ground mode, but not interrupt the controller unless the converted data is within/outside the specified range. figure 1.14. 10-bit adc block diagram adc0cf ad0ljst ad0sc0 ad0sc1 ad0sc2 ad0sc3 ad0sc4 10-bit sar adc ref sysclk adc0h 32 adc0cn ad0cm0 ad0cm1 ad0cm2 ad0wint ad0busy ad0int ad0tm ad0en timer 0 overflow timer 2 overflow timer 1 overflow start conversion 000 ad0busy (w) vdd adc0lth 18-to-1 amux ad0wint temp sensor 18-to-1 amux vdd p0.0 p0.7 001 010 011 100 cnvstr input window compare logic p1.0 p1.7 gnd p0.0 p0.7 p1.0 p1.7 101 timer 3 overflow adc0ltl adc0gth adc0gtl adc0l amx0p amx0p4 amx0p3 amx0p2 amx0p1 amx0p0 amx0n amx0n4 amx0n3 amx0n2 amx0n1 amx0n0 (+) (-) vref
rev. 1.5 29 c8051f330/1/2/3/4/5 1.8. comparators c8051f330/1/2/3/4/5 devices include an on-chip voltag e comparator that is e nabled/disabled and config - ured via user software. port i/o pins may be config ured as comparator inputs via a selection mux. two comparator outputs may be routed to a port pin if de sired: a latched output and /or an unlatched (asynchro - nous) output. comparator response time is programmabl e, allowing the user to select between high-speed and low-power modes. positive and negat ive hysteresis are also configurable. comparator interrupts may be generated on rising, fallin g, or both edges. when in idle mode, these inter - rupts may be used as a ?wake-up? source. comparator0 may also be configured as a reset source. figure 1.15 shows the comparator0 block diagram. figure 1.15. comparator0 block diagram vdd cpt0cn reset decision tree + - crossbar q q set clr d q q set clr d (synchronizer) gnd cp0 + p0.0 p0.2 p0.4 p0.6 cp0 - p0.1 p0.3 p0.5 p0.7 cp0en cp0out cp0rif cp0fif cp0hyp1 cp0hyp0 cp0hyn1 cp0hyn0 cpt0mx cmx0n3 cmx0n2 cmx0n1 cmx0n0 cmx0p3 cmx0p2 cmx0p1 cmx0p0 cpt0md cp0rie cp0fie cp0md1 cp0md0 cp0 cp0a p1.0 p1.2 p1.4 p1.6 p1.1 p1.3 p1.5 p1.7 cp0 interrupt 0 1 0 1 cp0rif cp0fif 0 1 cp0en 0 1 ea
c8051f330/1/2/3/4/5 30 rev. 1.5 1.9. 10-bit current output dac the c8051f330 device includes a 10-bit current-mo de digital-to-analog converter (ida0). the maximum current output of the ida0 can be adjusted for three different current settings; 0.5 ma, 1 ma, and 2 ma. ida0 features a flexible output update mechanism which allows for seamless full-scale changes and sup - ports jitter-free updates for waveform generation. th ree update modes are provided, allowing ida0 output updates on a write to ida0h, on a time r overflow, or on an external pin edge. figure 1.16. ida0 functional block diagram ida0 10 ida0 ida0cn ida0en ida0cm2 ida0cm1 ida0cm0 ida0omd1 ida0omd0 ida0h ida0l latch 8 2 ida0h timer 0 timer 1 timer 2 timer 3 cnvstr
rev. 1.5 31 c8051f330/1/2/3/4/5 2. absolute maximum ratings table 2.1. absolute maximum ratings parameter conditions min typ max units ambient temperature under bias ?55 ? 125 c storage temperature ?65 ? 150 c voltage on any port i/o pin or rst with respect to gnd ?0.3 ? 5.8 v voltage on v dd with respect to gnd ?0.3 ? 4.2 v maximum total current through v dd or gnd ? ? 500 ma maximum output current sunk by rst or any port pin ??100ma note: stresses above those listed under ?absolute maximum ra tings? may cause permanent damage to the device. this is a stress rating only and functional operation of the devices at those or any other conditions above those indicated in the operation list ings of this specification is not implied. exposure to maximum rating conditions for extended periods may affect device reliability.
c8051f330/1/2/3/4/5 32 rev. 1.5 3. global electrical characteristics table 3.1. global electrical characteristics ?40 to +85 c, 25 mhz system clock unless otherwise specified. parameter conditions min typ max units digital supply voltage v rst 1 3.0 3.6 v digital supply ram data retention voltage ?1.5? v sysclk (system clock) (note 2) 0?25mhz t sysh (sysclk high time) 18 ? ? ns t sysl (sysclk low time) 18 ? ? ns specified operating temperature range ?40 ? +85 c digital supply current?cpu active (normal mode, fetching instructions from flash) i dd (note 3) v dd = 3.6 v, f = 25 mhz ? 10.7 11.7 ma v dd = 3.0 v, f = 25 mhz ? 7.8 8.3 ma v dd = 3.0 v, f = 1 mhz ? 0.38 ? ma v dd = 3.0 v, f = 80 khz ? 31 ? a i dd supply sensitivity (note 3) f = 25 mhz ? 65 ? %/v f = 1 mhz ? 61 ? %/v i dd frequency sensitivity (note 3, note 4) v dd = 3.0 v, f <= 15 mhz, t = 25 c ? 0.38 ? ma/mhz v dd = 3.0 v, f > 15 mhz, t = 25 c ? 0.21 ? ma/mhz v dd = 3.6 v, f <= 15 mhz, t = 25 c ? 0.53 ? ma/mhz v dd = 3.6 v, f > 15 mhz, t = 25 c ? 0.27 ? ma/mhz
rev. 1.5 33 c8051f330/1/2/3/4/5 other electrical characteristics tables are found in the data sheet section corresponding to the associated peripherals. for more information on electrical characte ristics for a specific perip heral, refer to the page indicated in table 3.2. digital supply current?cpu inactive (idle mode , not fetching instructions from flash) i dd (note 3) v dd = 3.6 v, f = 25 mhz ? 4.8 5.2 ma v dd = 3.0 v, f = 25 mhz ? 3.8 4.1 ma v dd = 3.0 v, f = 1 mhz ? 0.20 ? ma v dd = 3.0 v, f = 80 khz ? 16 ? a i dd supply sensitivity (note 3) f = 25 mhz ? 43 ? %/v f = 1 mhz ? 55 ? %/v i dd frequency sensitivity (note 3, note 5) v dd = 3.0 v, f <= 1 mhz, t = 25 c ? 0.20 ? ma/mhz v dd = 3.0 v, f > 1 mhz, t = 25 c ? 0.15 ? ma/mhz v dd = 3.6 v, f <= 1 mhz, t = 25 c ? 0.24 ? ma/mhz v dd = 3.6 v, f > 1 mhz, t = 25 c ? 0.19 ? ma/mhz digital supply current (stop mode, shutdown) oscillator not running, v dd monitor disabled ?< 0.1? a notes: 1. given in table 10.1 on page 104 . 2. sysclk must be at least 32 khz to enable debugging. 3. based on device characterization data; not production tested. 4. idd can be estimated for frequencies <= 15 mhz by simply multiplying the frequency of interest by the frequency sensitivity number for that range . when using these numbers to estimate i dd for >15 mhz, the estimate should be the current at 25 mhz minus the difference in current indicated by the frequency sensitivity number. for example: v dd = 3.0 v; f = 20 mhz, i dd = 7.8 ma - (25 mhz - 20 mhz) * 0.21 ma/mhz = 6.75 ma. 5. idle idd can be estimated for frequencies <= 1 mhz by simply multiplying the frequency of interest by the frequency sensitivity number fo r that range. when using these numbers to estimate idle i dd for >1 mhz, the estimate should be the current at 25 mhz minus the difference in current indicated by the frequency sensitivity number. for example: v dd = 3.0 v; f = 5 mhz, idle i dd = 4.8 ma - (25 mhz - 5 mhz) * 0.15 ma/mhz = 1.8 ma. table 3.1. global electr ical characteristics ?40 to +85 c, 25 mhz system clock unless otherwise specified. parameter conditions min typ max units
c8051f330/1/2/3/4/5 34 rev. 1.5 table 3.2. index to electrical ch aracteristics tables peripheral electrical characteristics page no. adc0 electrical characteristics 57 idac electrical characteristics 62 voltage reference electr ical characteristics 65 comparator electrical characteristics 72 reset electrical characteristics 104 flash electrical characteristics 106 internal oscillator electrical characteristics 124 port i/o dc electrical characteristics 136
rev. 1.5 35 c8051f330/1/2/3/4/5 4. pinout and package definitions table 4.1. pin definitions for th e c8051f330/1/2/3/4/5 name pin ?f330/1/2/ 3/4/5 pin ?f330d/ ?f330-gp type description v dd 3 6 power supply voltage. gnd 2 5 ground. rst / c2ck 4 7 d i/o d i/o device reset. open-drain output of internal por or v dd monitor. an external source ca n initiate a system reset by driving this pin low for at least 10 s. clock signal for the c2 debug interface. p2.0/ c2d 5 8 d i/o d i/o port 3.0. see section 14 for a complete description. bi-directional data signal for the c2 debug interface. p0.0/ vref 1 4 d i/o or a in a in port 0.0. see section 14 for a complete description. external vref input. see section 7 for a complete descrip - tion. p0.1 ida0 20 3 d i/o or a in aout port 0.1. see section 14 for a complete description. ida0 output. see section 6 for a complete description. p0.2/ xtal1 19 2 d i/o or a in a in port 0.2. see section 14 for a complete description. external clock input. this pi n is the external oscillator return for a crystal or resonator. see section 13 for a com - plete description. p0.3/ xtal2 18 1 d i/o or a in a i/o or d in port 0.3. see section 14 for a complete description. external clock output. for an ex ternal crystal or resonator, this pin is the excitation driver. this pin is the external clock input for cmos, capacitor, or rc oscillator configurations. see section 13 for a complete description. p0.4 17 20 d i/o or a in port 0.4. see section 14 for a complete description. p0.5 16 19 d i/o or a in port 0.5. see section 14 for a complete description.
c8051f330/1/2/3/4/5 36 rev. 1.5 p0.6/ cnvstr 15 18 d i/o or a in d in port 0.6. see section 14 for a complete description. adc0 external convert start or ida0 update source input. see section 5 and section 6 for a complete description. p0.7 14 17 d i/o or a in port 0.7. see section 14 for a complete description. p1.0 13 16 d i/o or a in port 1.0. see section 14 for a complete description. p1.1 12 15 d i/o or a in port 1.1. see section 14 for a complete description. p1.2 11 14 d i/o or a in port 1.2. see section 14 for a complete description. p1.3 10 13 d i/o or a in port 1.3. see section 14 for a complete description. p1.4 9 12 d i/o or a in port 1.4. see section 14 for a complete description. p1.5 8 11 d i/o or a in port 1.5. see section 14 for a complete description. p1.6 7 10 d i/o or a in port 1.6. see section 14 for a complete description. p1.7 6 9 d i/o or a in port 1.7. see section 14 for a complete description. table 4.1. pin definitions for the c8051f330/1/2/3/4/5 (continued) name pin ?f330/1/2/ 3/4/5 pin ?f330d/ ?f330-gp type description
rev. 1.5 37 c8051f330/1/2/3/4/5 figure 4.1. qfn-20 pino ut diagram (top view) 3 4 5 1 2 8 9 10 6 7 13 12 11 15 14 18 19 20 16 17 p0.0 gnd vdd /rst/c2ck p2.0/c2d p1.7 p1.6 p1.5 p1.4 p1.3 p1.2 p1.1 p1.0 p0.7 p0.6 p0.5 p0.4 p0.3 p0.2 p0.1 c8051f330/1/2/3/4/5 top view gnd gnd
c8051f330/1/2/3/4/5 38 rev. 1.5 figure 4.2. qfn-20 package drawing table 4.2. qfn-20 package dimensions mm min typ max a 0.80 0.90 1.00 a1 0 0.02 0.05 a2 0 0.65 1.00 a3 ? 0.25 ? b 0.18 0.23 0.30 d?4.00? d2 2.00 2.15 2.25 e?4.00? e2 2.00 2.15 2.25 e?0.5? l 0.45 0.55 0.65 n?20? nd ? 5 ? ne ? 5 ? r0.09? ? aa ? 0.435 ? bb ? 0.435 ? cc ? 0.18 ? dd ? 0.18 ? 18 1 e d a2 a a1 e a3 e2 r e l bottom view side view 2 3 5 6 7 10 15 14 12 11 20 19 16 e2 2 d2 8 13 d2 2 4 x e 4 x e detail 1 detail 1 aa bb cc dd b 4 9 17
rev. 1.5 39 c8051f330/1/2/3/4/5 figure 4.3. qfn-20 solder paste recommendation top view e e d b l 0.50 mm 0.30 mm 0.10 mm 0.20 mm 0.85 mm 0.50 mm 0.30 mm 0.10 mm 0.20 mm 0.85 mm e2 d2 0.35 mm 0.35 mm 0.60 mm 0.30 mm 0.20 mm 0.70 mm 0.40 mm 0.60 mm 0.20 mm 0.20 mm 0.50 mm 0.50 mm
c8051f330/1/2/3/4/5 40 rev. 1.5 figure 4.4. typical qf n-20 landing diagram top view e d b l 0.50 mm 0.30 mm 0.10 mm 0.20 mm 0.85 mm 0.50 mm 0.30 mm 0.10 mm 0.20 mm 0.85 mm 0.35 mm 0.35 mm e2 d2 e optional gnd connection 0.20 mm 0.20 mm 0.50 mm 0.50 mm
rev. 1.5 41 c8051f330/1/2/3/4/5 figure 4.5. pdip-20 pinout diagram (top view) p0.3 p0.4 p0.5 p0.6 p0.7 p1.0 p1.1 p1.2 p1.3 p1.4 c8051f330d/gp p0.2 p0.1 p0.0 gnd vdd /rst p2.0 p1.7 p1.6 p1.5 1 2 3 4 5 6 7 8 9 10 20 19 18 17 16 15 14 13 12 11
c8051f330/1/2/3/4/5 42 rev. 1.5 figure 4.6. pdip-20 package drawing table 4.3. pdip-20 package dimensions inches min typ max a??0.210 a1 0.015 ? ? a2 0.115 0.130 0.195 b 0.014 0.018 0.022 b1 0.014 0.018 0.020 b2 0.045 0.060 0.070 b3 0.030 0.039 0.045 c .008 0.010 0.014 c1 0.008 0.010 0.011 d 0.980 1.030 1.060 d1 0.005 ? ? e 0.300 0.310 0.325 e1 0.240 0.250 0.280 e ? 0.100 ? ea ? 0.300 ? eb ? ? 0.430 ec 0.000 ? 0.060 l 0.115 0.130 0.150 1 20 pin 1 identifier e1 e b2 b a1 d1 d1 a2 a l b3 d e ea eb ec 0.015" b pin dimensions (bottom view) b1 c1 c side view side view top view base metal
rev. 1.5 43 c8051f330/1/2/3/4/5 5. 10-bit adc (adc0, c8051f330/2/4 only) the adc0 subsystem for the c8051f330/2/4 consists of two analog multiplexers (referred to collectively as amux0) with 16 total input selections, and a 200 ksps, 10-bit successive-a pproximation-register adc with integrated track-and-hold and programmable window detector. the amux0, data conversion modes, and window detector are all configurable under softwa re control via the special function registers shown in figure 5.1 . adc0 operates in both single-ended and diffe rential modes, and may be configured to mea - sure ports0-1, the temperature sensor output, or v dd with respect to ports0-1 or gnd. the adc0 sub - system is enabled only when the ad0en bit in the adc0 control register (a dc0cn) is set to logic 1. the adc0 subsystem is in low power sh utdown when this bit is logic 0. figure 5.1. adc0 functional block diagram 5.1. analog multiplexer amux0 selects the positive and negative inputs to th e adc. any of the following may be selected as the positive input: ports0-1, the on-chip temperat ure sensor, or the positive power supply (v dd ). any of the fol - lowing may be selected as the negative input: ports0-1, v ref , or gnd. when gnd is selected as the negative input, adc0 operates in single-ended mode; al l other times, adc0 operates in differential mode. the adc0 input channels are selected in the amx0p and amx0n registers as described in sfr definition 5.1 and sfr definition 5.2 . the conversion code format differs between single -ended and differential modes. the registers adc0h and adc0l contain the high and low bytes of the output conversion code from the adc at the completion of each conversion. data can be right-justified or le ft-justified, depending on the setting of the ad0ljst. when in single-ended mode, conversion codes are represented as 10-bit unsigned integers. inputs are adc0cf ad0ljst ad0sc0 ad0sc1 ad0sc2 ad0sc3 ad0sc4 10-bit sar adc ref sysclk adc0h 32 adc0cn ad0cm0 ad0cm1 ad0cm2 ad0wint ad0busy ad0int ad0tm ad0en timer 0 overflow timer 2 overflow timer 1 overflow start conversion 000 ad0busy (w) vdd adc0lth 18-to-1 amux ad0wint temp sensor 18-to-1 amux vdd p0.0 p0.7 001 010 011 100 cnvstr input window compare logic p1.0 p1.7 gnd p0.0 p0.7 p1.0 p1.7 101 timer 3 overflow adc0ltl adc0gth adc0gtl adc0l amx0p amx0p4 amx0p3 amx0p2 amx0p1 amx0p0 amx0n amx0n4 amx0n3 amx0n2 amx0n1 amx0n0 (+) (-) vref
c8051f330/1/2/3/4/5 44 rev. 1.5 measured from ?0? to vref x 1023/1024. example codes are shown below for both right-justified and left- justified data. unused bits in the a dc0h and adc0l registers are set to ?0?. when in differential mode, conversion codes are represented as 10-bit signed 2?s complement numbers. inputs are measured from ? vref to vref x 511/512. example codes are shown below for both right-jus - tified and left-justified data. for right-justified data, the unused msbs of adc0h are a sign-extension of the data word. for left-justified data, the unused lsbs in the adc0l register are set to ?0?. important note about adc0 input configuration: port pins selected as adc0 inputs should be config - ured as analog inputs, and should be skipped by the digital crossbar. to configure a port pin for analog input, set to ?0? the corresponding bit in register pnmdin (for n = 0,1). to force the crossbar to skip a port pin, set to ?1? the corresponding bit in register pnskip (for n = 0,1). see section ?14. port input/output? on page 125 for more port i/o configuration details. 5.2. temperature sensor the typical temperature sensor transfer function is shown in figure 5.2 . the output voltage (v temp ) is the positive adc input when the temperature sensor is selected by bits amx0p4 ? 0 in register amx0p. input voltage right-justified adc0h:adc0l (ad0ljst = 0) left-justified adc0h:adc0l (ad0ljst = 1) vref x 1023/1024 0x03ff 0xffc0 vref x 512/1024 0x0200 0x8000 vref x 256/1024 0x0100 0x4000 0 0x0000 0x0000 input voltage right-jus tified adc0h:adc0l (ad0ljst = 0) left-justified adc0h:adc0l (ad0ljst = 1) vref x 511/512 0x01ff 0x7fc0 vref x 256/512 0x0100 0x4000 0 0x0000 0x0000 ?vref x 256/512 0xff00 0xc000 ?vref 0xfe00 0x8000
rev. 1.5 45 c8051f330/1/2/3/4/5 figure 5.2. typical temperatur e sensor transfer function 5.3. modes of operation adc0 has a maximum conversion speed of 200 ksps. the adc0 conversion clock is a divided version of the system clock, determined by the ad0sc bits in th e adc0cf register (system clock divided by (ad0sc + 1) for 0 ad0sc 31). 0 -50 50 100 (celsius) 0.500 0.600 0.700 0.800 0.900 (volts) v temp = 2.86(temp c ) + 776 mv 1.000
c8051f330/1/2/3/4/5 46 rev. 1.5 5.3.1. starting a conversion a conversion can be initiated in one of six ways, depending on the programmed states of the adc0 start of conversion mode bits (ad0cm2 ? 0) in register adc0cn. conversions may be initiated by one of the fol - lowing: 1. writing a ?1? to the ad0busy bit of register adc0cn 2. a timer 0 overflow (i.e., timed continuous conversions) 3. a timer 2 overflow 4. a timer 1 overflow 5. a rising edge on the cnvstr input signal (pin p0.6) 6. a timer 3 overflow writing a ?1? to ad0busy provides software contro l of adc0 whereby conversions are performed "on- demand". during conversion, the ad0busy bit is set to logic 1 and reset to logic 0 when the conversion is complete. the falling edge of ad0bu sy triggers an interrupt (when enabl ed) and sets the adc0 interrupt flag (ad0int). note: when polling for adc conversion completions, the adc0 in terrupt flag (ad0int) should be used. converted data is available in th e adc0 data registers, adc0h:adc0l, when bit ad0int is logic 1. note that when timer 2 or timer 3 overflows are used as the co nversion source, low byte over - flows are used if timer 2/3 is in 8-bit mode; high by te overflows are used if timer 2/3 is in 16-bit mode. see section ?18. timers? on page 179 for timer configuration. important note about using cnvstr: the cnvstr input pin also functions as port pin p0.6. when the cnvstr input is used as the adc0 conversion source, port pin p0.6 should be skipped by the digital crossbar. to configure the crossbar to skip p0 .6, set to ?1? bit6 in register p0skip. see section ?14. port input/output? on page 125 for details on port i/o configuration.
rev. 1.5 47 c8051f330/1/2/3/4/5 5.3.2. tracking modes each adc0 conversion must be preceded by a minimum tracking time in order for the converted result to be accurate. the minimum tracking time is given in ta b l e 5.1 . the ad0tm bit in register adc0cn controls the adc0 track-and-hold mode. in its default state, the adc0 input is continuously tracked, except when a conversion is in progress. when the ad0tm bit is logic 1, adc0 operates in low-power track-and-hold mode. in this mode, each conversion is preceded by a tracking period of 3 sar clocks (after the start-of- conversion signal). when the cnvstr signal is used to initiate conversions in low-power trac king mode, adc0 tracks only when cnvstr is low; conversion begins on the rising edge of cnvstr (see figure 5.3 ). tracking can also be disabled (shutdown) w hen the device is in low power standby or sleep modes. low-power track-and-hold mode is also usef ul when amux settings are frequently changed, due to the settling time requirements described in section ?5.3.3. settling time requirements? on page 48 . figure 5.3. 10-bit adc track and conversion example timing write '1' to ad0busy, timer 0, timer 2, timer 1, timer 3 overflow (ad0cm[2:0]=000, 001,010 011, 101) ad0tm=1 track convert low power mode ad0tm=0 track or convert convert track low power or convert sar clocks 123456789101112 123456789 sar clocks b. adc0 timing for internal trigger source 123456789 cnvstr (ad0cm[2:0]=100) ad0tm=1 a. adc0 timing for external trigger source sar clocks track or convert convert track ad0tm=0 track convert low power mode low power or convert 10 11 13 14 10 11
c8051f330/1/2/3/4/5 48 rev. 1.5 5.3.3. settling time requirements when the adc0 input configuration is changed (i.e., a different amux0 selection is made), a minimum tracking time is required before an accurate conversion can be performed. this tracking time is determined by the amux0 resistance, the adc0 sampling capacita nce, any external source resistance, and the accu - racy required for the conversion. note that in low-po wer tracking mode, three sar clocks are used for tracking at the start of every conv ersion. for most applications, these three sar clocks will meet the mini - mum tracking time requirements. figure 5.4 shows the equivalent adc0 input circuits for both differential and single-ended modes. notice that the equivalent time constant for both input circ uits is the same. the required adc0 settling time for a given settling accuracy (sa) may be approximated by equation 5.1 . when measuring the temperature sensor output or v dd with respect to gnd, r total reduces to r mux . see ta b l e 5.1 for adc0 minimum settling time requirements. equation 5.1. adc0 settling time requirements where: sa is the settling accuracy, given as a fraction of an lsb (for example, 0.25 to settle within 1/4 lsb) t is the required settling time in seconds r total is the sum of the amux0 resistance and any external source resistance. n is the adc resolution in bits (10). figure 5.4. adc0 eq uivalent input circuits t 2 n sa ------ - ?? ?? r total c sample ln = r mux = 5k rc input = r mux * c sample r mux = 5k c sample = 5pf c sample = 5pf mux select mux select differential mode px.x px.x r mux = 5k c sample = 5pf rc input = r mux * c sample mux select single-ended mode px.x
rev. 1.5 49 c8051f330/1/2/3/4/5 sfr definition 5.1. amx0p: amux0 positive channel select bits7 ? 5: unused. read = 000b; write = don?t care. bits4 ? 0: amx0p4 ? 0: amux0 positive input selection r r r r/w r/w r/w r/w r/w reset value - - - amx0p4 amx0p3 amx0p2 amx0p1 amx0p0 00011111 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xbb amx0p4?0 adc0 positive input 00000 p0.0 00001 p0.1 00010 p0.2 00011 p0.3 00100 p0.4 00101 p0.5 00110 p0.6 00111 p0.7 01000 p1.0 01001 p1.1 01010 p1.2 01011 p1.3 01100 p1.4 01101 p1.5 01110 p1.6 01111 p1.7 10000 temp sensor 10001 v dd 10010 ? 11111 no input selected
c8051f330/1/2/3/4/5 50 rev. 1.5 sfr definition 5.2. amx0n: amux0 negative channel select bits7?5: unused. read = 000b; write = don?t care. bits4?0: amx0n4?0: amux0 negative input selection. note that when gnd is selected as the nega tive input, adc0 operates in single-ended mode. for all other negative input select ions, adc0 operates in differential mode. r r r r/w r/w r/w r/w r/w reset value - - - amx0n4 amx0n3 amx0n2 amx0n1 amx0n0 00011111 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xba amx0n4?0 adc0 negative input 00000 p0.0 00001 p0.1 00010 p0.2 00011 p0.3 00100 p0.4 00101 p0.5 00110 p0.6 00111 p0.7 01000 p1.0 01001 p1.1 01010 p1.2 01011 p1.3 01100 p1.4 01101 p1.5 01110 p1.6 01111 p1.7 10000 vref 10001 gnd (adc in single-ended mode) 10010?11111 no input selected
rev. 1.5 51 c8051f330/1/2/3/4/5 sfr definition 5.3. adc0cf: adc0 configuration sfr definition 5.4. adc0h: adc0 data word msb sfr definition 5.5. adc0l: adc0 data word lsb bits7 ? 3: ad0sc4 ? 0: adc0 sar conversion clock period bits. sar conversion clock is derived from sys tem clock by the following equation, where ad0sc refers to the 5-bit value held in bits ad0sc4 ? 0. sar conversion clock require- ments are given in table 5.1. bit2: ad0ljst: adc0 left justify select. 0: data in adc0h:adc0l r egisters are right-justified. 1: data in adc0h:adc0l r egisters are left-justified. bits1 ? 0: unused. read = 00b; write = don?t care. r/wr/wr/wr/wr/wr/w r rreset value ad0sc4 ad0sc3 ad0sc2 ad0sc1 ad0sc0 ad0ljst - - 11111000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xbc ad0sc sysclk clk sar --------------------- - 1 ? = bits7 ? 0: adc0 data word high-order bits. for ad0ljst = 0: bits 7 ? 2 are the sign extension of bit1. bits 1 ? 0 are the upper 2 bits of the 10-bit adc0 data word. for ad0ljst = 1: bits 7 ? 0 are the most-significant bits of the 10-bit adc0 data word. r/w r/w r/w r/w r/w r/w r/w r/w reset value 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xbe bits7 ? 0: adc0 data word low-order bits. for ad0ljst = 0: bits 7 ? 0 are the lower 8 bits of the 10-bit data word. for ad0ljst = 1: bits 7 ? 6 are the lower 2 bits of the 10-bit data word. bits 5 ? 0 will always read ?0?. r/w r/w r/w r/w r/w r/w r/w r/w reset value 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xbd
c8051f330/1/2/3/4/5 52 rev. 1.5 sfr definition 5.6. adc0cn: adc0 control bit7: ad0en: adc0 enable bit. 0: adc0 disabled. adc0 is in low-power shutdown. 1: adc0 enabled. adc0 is active and ready for data conversions. bit6: ad0tm: adc0 track mode bit. 0: normal track mode: when adc0 is enabled , tracking is continuous unless a conversion is in progress. 1: low-power track mode: tracking defined by ad0cm2 ? 0 bits (see below). bit5: ad0int: adc0 conversion complete interrupt flag. 0: adc0 has not completed a data conversi on since the last time ad0int was cleared. 1: adc0 has completed a data conversion. bit4: ad0busy: adc0 busy bit. read: 0: adc0 conversion is complete or a conversion is not currently in progress. ad0int is set to logic 1 on the fa lling edge of ad0busy. 1: adc0 conversion is in progress. write: 0: no effect. 1: initiates adc0 co nversion if ad0cm2 ? 0 = 000b bit3: ad0wint: adc0 window compare interrupt flag. 0: adc0 window comparison data match has not occurred since this flag was last cleared. 1: adc0 window comparison data match has occurred. bits2 ? 0: ad0cm2 ? 0: adc0 start of conversion mode select. when ad0tm = 0: 000: adc0 conversion initiated on every write of ?1? to ad0busy. 001: adc0 conversion initiated on overflow of timer 0. 010: adc0 conversion initiat ed on overflow of timer 2. 011: adc0 conversion initiated on overflow of timer 1. 100: adc0 conversion initiated on rising edge of external cnvstr. 101: adc0 conversion initiated on overflow of timer 3. 11x: reserved. when ad0tm = 1: 000: tracking initiated on write of ?1? to ad 0busy and lasts 3 sar clocks, followed by con- version. 001: tracking initiated on overflow of timer 0 and lasts 3 sar clocks, followed by conver- sion. 010: tracking initiated on overflow of timer 2 and lasts 3 sar clocks, followed by conver- sion. 011: tracking initiated on overflow of timer 1 and lasts 3 sar clocks, followed by conver- sion. 100: adc0 tracks only when cnvstr input is logic low; conversion starts on rising cnvstr edge. 101: tracking initiated on overflow of timer 3 and lasts 3 sar clocks, followed by conver- sion. 11x: reserved. r/w r/w r/w r/w r/w r/w r/w r/w reset value ad0en ad0tm ad0int ad0busy ad0wi nt ad0cm2 ad0cm1 ad0cm0 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: (bit addressable) 0xe8
rev. 1.5 53 c8051f330/1/2/3/4/5 5.4. programmable window detector the adc programmable window detector continuously compares the adc0 output registers to user-pro - grammed limits, and notifies the system when a desired co ndition is detected. this is especially effective in an interrupt-driven system, saving code space and cpu ba ndwidth while delivering faster system response times. the window detector interrupt flag (ad0wint in register adc0cn) can also be used in polled mode. the adc0 greater-t han (adc0gth, adc0gtl) and less-than (adc0lth, adc0ltl) reg - isters hold the comparison values. the window detector flag can be programmed to indicate when mea - sured data is inside or outside of the user-progr ammed limits, depending on the contents of the adc0 less-than and adc0 greater-than registers. sfr definition 5.7. adc0gth: adc0 greater-than data high byte sfr definition 5.8. adc0gtl: adc0 greate r-than data low byte bits7 ? 0: high byte of adc0 greater-than data word r/w r/w r/w r/w r/w r/w r/w r/w reset value 11111111 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xc4 bits7 ? 0: low byte of adc0 greater-than data word r/w r/w r/w r/w r/w r/w r/w r/w reset value 11111111 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xc3
c8051f330/1/2/3/4/5 54 rev. 1.5 sfr definition 5.9. adc0lth: adc0 less-than data high byte sfr definition 5.10. adc0ltl: adc0 less-than data low byte bits7 ? 0: high byte of adc0 less-than data word r/w r/w r/w r/w r/w r/w r/w r/w reset value 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xc6 bits7 ? 0: low byte of adc0 less-than data word r/w r/w r/w r/w r/w r/w r/w r/w reset value 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xc5
rev. 1.5 55 c8051f330/1/2/3/4/5 5.4.1. window detector in single-ended mode figure 5.5 shows two example window comparisons fo r right-justified, single-ended data, with adc0lth:adc0ltl = 0x0080 (128d) and adc0gth:adc0gtl = 0x0040 (64d). in single-ended mode, the input voltage can range from ?0? to vref x (1023/ 1024) with respect to gnd, and is represented by a 10-bit unsigned intege r value. in the left example, an ad0win t interrupt will be gener ated if the adc0 conversion word (adc0h:adc0l) is within the range defined by adc0gth:adc0gtl and adc0lth:adc0ltl (if 0x0040 < adc0h:adc0l < 0x0080). in the right example, and ad0wint interrupt will be generated if the adc0 conversion word is outside of t he range defined by the adc0gt and adc0lt registers (if adc0h:adc0l < 0x0040 or adc0h:adc0l > 0x0080). figure 5.6 shows an exam - ple using left-justified data with the same comparison values. figure 5.5. adc window co mpare example: right-justified single-ended data figure 5.6. adc window co mpare example: left-justified single-ended data 0x03ff 0x0081 0x0080 0x007f 0x0041 0x0040 0x003f 0x0000 0 input voltage (px.x - gnd) vref x (1023/1024) vref x (128/1024) vref x (64/1024) ad0wint=1 ad0wint not affected ad0wint not affected adc0lth:adc0ltl adc0gth:adc0gtl 0x03ff 0x0081 0x0080 0x007f 0x0041 0x0040 0x003f 0x0000 0 input voltage (px.x - gnd) vref x (1023/1024) vref x (128/1024) vref x (64/1024) ad0wint not affected ad0wint=1 ad0wint=1 adc0h:adc0l adc0h:adc0l adc0gth:adc0gtl adc0lth:adc0ltl 0xffc0 0x2040 0x2000 0x1fc0 0x1040 0x1000 0x0fc0 0x0000 0 input voltage (px.x - gnd) vref x (1023/1024) vref x (128/1024) vref x (64/1024) ad0wint=1 ad0wint not affected ad0wint not affected adc0lth:adc0ltl adc0gth:adc0gtl 0xffc0 0x2040 0x2000 0x1fc0 0x1040 0x1000 0x0fc0 0x0000 0 input voltage (px.x - gnd) vref x (1023/1024) vref x (128/1024) vref x (64/1024) ad0wint not affected ad0wint=1 ad0wint=1 adc0h:adc0l adc0h:adc0l adc0lth:adc0ltl adc0gth:adc0gtl
c8051f330/1/2/3/4/5 56 rev. 1.5 5.4.2. window detector in differential mode figure 5.7 shows two example window comparisons for right-justified, differential data, with adc0lth:adc0ltl = 0x0040 (+64d) and adc0gth:adc0gth = 0xffff ( ? 1d). in differential mode, the measurable voltage between the input pins is between ?vref and vref x (511/512). output codes are represented as 10-bit 2s complement signed integers. in the left example, an ad0wint interrupt will be generated if the adc0 conversion word (a dc0h:adc0l) is within the range defined by adc0gth:adc0gtl and adc0lth:adc0ltl (if 0xffff (?1d) < adc0h:adc0l < 0x0040 (64d)). in the right example, an ad0wint interrupt will be generated if the adc0 conver sion word is outside of the range defined by the adc0gt and adc0lt registers (if adc0h:adc0l < 0xffff (?1d) or adc0h:adc0l > 0x0040 (+64d)). figure 5.8 shows an example using left-justified data with the same comparison values. figure 5.7. ad c window compare example: righ t-justified differential data figure 5.8. adc window compare exampl e: left-justified differential data 0x01ff 0x0041 0x0040 0x003f 0x0000 0xffff 0xfffe 0x0200 -vref input voltage (px.x - px.x) vref x (511/512) vref x (64/512) vref x (-1/512) 0x01ff 0x0041 0x0040 0x003f 0x0000 0xffff 0xfffe 0x0200 -vref input voltage (px.x - px.x) vref x (511/512) vref x (64/512) vref x (-1/512) ad0wint=1 ad0wint not affected ad0wint not affected adc0lth:adc0ltl adc0gth:adc0gtl ad0wint not affected ad0wint=1 ad0wint=1 adc0h:adc0l adc0h:adc0l adc0gth:adc0gtl adc0lth:adc0ltl 0x7fc0 0x1040 0x1000 0x0fc0 0x0000 0xffc0 0xff80 0x8000 -vref input voltage (px.x - px.y) vref x (511/512) vref x (64/512) vref x (-1/512) 0x7fc0 0x1040 0x1000 0x0fc0 0x0000 0xffc0 0xff80 0x8000 -vref input voltage (px.x - px.x) vref x (511/512) vref x (64/512) vref x (-1/512) ad0wint=1 ad0wint not affected ad0wint not affected adc0lth:adc0ltl adc0gth:adc0gtl ad0wint not affected adc0gth:adc0gtl ad0wint=1 ad0wint=1 adc0h:adc0l adc0h:adc0l adc0lth:adc0ltl
rev. 1.5 57 c8051f330/1/2/3/4/5 table 5.1. adc0 electrical characteristics v dd = 3.0 v, vref = 2.40 v (refsl=0), ? 40 to +85 c unless otherwise specified. parameter conditions min typ max units dc accuracy resolution 10 bits integral nonlinearity ? 0.5 1 lsb differential nonlinearity guaranteed monotonic ? 0.5 1 lsb offset error -15 0 15 lsb full scale error -15 ?1 15 lsb offset temperature coefficient ? 10 ? ppm/c dynamic perf ormance (10 khz sine-wave single-ended input, 1 db below full scale, 200 ksps) signal-to-noise plus distortion 53 55.5 ? db total harmonic distortion up to the 5th harmonic ? ?67 ? db spurious-free dynamic range ? 78 ? db conversion rate sar conversion clock ? ? 3 mhz conversion time in sar clocks 10 ? ? clocks track/hold acquisition time 300 ? ? ns throughput rate ? ? 200 ksps analog inputs adc input voltage range single ended (ain+ ? gnd) differential (ain+ ? ain?) 0 ?vref ? vref vref v v absolute pin voltage with respect to gnd single ended or differential 0 ? v dd v input capacitance ? 5 ? pf temperature sensor linearity ? 0.2 ? c absolute accuracy ? 3 ? c gain ? 2.86 ? mv/c gain error* ? 33.5 ? v/c offset te m p = 0 c ? 776 ? mv offset error* ? 8.51 ? mv power specifications power supply current (v dd supplied to adc0) operating mode, 200 ksps ? 400 900 a power supply rejection ? 0.3 ? mv/v *note: represents one standard deviation from the mean.
c8051f330/1/2/3/4/5 58 rev. 1.5
rev. 1.5 59 c8051f330/1/2/3/4/5 6. 10-bit current mode dac (ida0, c8051f330 only) the c8051f330 device includes a 10-bit current-mo de digital-to-analog converter (idac). the maximum current output of the idac can be adjusted for three different current settings; 0.5 ma, 1 ma, and 2 ma. the idac is enabled or disabled with the ida0 en bit in the ida0 control register (see sfr definition 6.1 ). when ida0en is set to ?0?, the idac port pin (p0.1) behaves as a normal gpio pin. when ida0en is set to ?1?, the digital output drivers and weak pullup for th e idac pin are automatically disabled, and the pin is connected to the idac output. an internal bandgap bias generator is used to generate a reference current for the idac whenever it is enabled. when using the idac , bit 1 in the p0skip register should be set to ?1?, to force the crossbar to skip the idac pin. 6.1. ida0 output scheduling ida0 features a flexible output update mechanism which allows for seamless full-scale changes and sup - ports jitter-free updates for wavefo rm generation. three update modes are provided, allowing idac output updates on a write to ida0h, on a time r overflow, or on an external pin edge. 6.1.1. update output on-demand in its default mode (ida0cn.[6:4] = ?111?) the ida0 output is updated ?on-demand? on a write to the high- byte of the ida0 data register (ida0h). it is important to note that writes to ida0l are held in this mode, and have no effect on the ida0 output until a write to ida0h takes place. if writing a full 10-b it word to the idac data registers, the 10-bit data word is written to the low byte (ida0l) and high byte (ida0h) data reg - isters. data is latched into ida0 after a write to the ida0h register, so the write sequence should be ida0l followed by ida0h if the full 10-bit resolution is required. the idac can be used in 8-bit mode by initializing ida0l to the desired value (typically 0x00), and writ ing data to only ida0h (see section 6.2 for information on the format of the 10-bit idac data word within the 16-bit sfr space). figure 6.1. ida0 fun ctional block diagram ida0 10 ida0 ida0cn ida0en ida0cm2 ida0cm1 ida0cm0 ida0omd1 ida0omd0 ida0h ida0l latch 8 2 ida0h timer 0 timer 1 timer 2 timer 3 cnvstr
c8051f330/1/2/3/4/5 60 rev. 1.5 6.1.2. update output based on timer overflow similar to the adc operation, in which an adc conv ersion can be initiated by a timer overflow indepen - dently of the processor, the idac outputs can use a timer overflow to schedule an output update event. this feature is useful in systems where the idac is used to generate a waveform of a defined sampling rate by eliminating the effects of variable interrupt la tency and instruction execution on the timing of the idac output. when the ida0cm bits (ida0cn.[6:4]) are se t to ?000?, ?001?, ?010? or ?011?, writes to both idac data registers (ida0l and ida0h) are held until an associated timer overflow event (timer 0, timer 1, timer 2 or timer 3, respectively) occurs, at which time the ida0h:ida0l contents are copied to the idac input latches, a llowing the idac output to change to the new value. 6.1.3. update output based on cnvstr edge the idac output can also be configured to update on a rising edge, falling edge, or both edges of the external cnvstr signal. when the ida0cm bits (ida0cn.[6:4]) are set to ?100?, ?101?, or ?110?, writes to both idac data registers (ida0l and ida0h) are held until an edge occurs on the cnvstr input pin. the particular setting of the ida0cm bi ts determines whether idac outputs are updated on ri sing, falling, or both edges of cnvstr. when a corresponding edge oc curs, the ida0h:ida0l contents are copied to the idac input latches, allowing the idac output to change to the new value. 6.2. idac output mapping the idac data registers (ida0h and ida0l) are left-j ustified, meaning that the eight msbs of the idac output word are mapped to bits 7 ? 0 of the ida0h register, and the two lsbs of the idac output word are mapped to bits 7 and 6 of the ida0l register. the data word mapping for the idac is shown in figure 6.2 . figure 6.2. ida0 data word mapping the full-scale output current of the idac is selected using the ida0omd bits (ida0cn[1:0]). by default, the idac is set to a full-scale output current of 2 ma. the ida0omd bits can also be configured to provide full-scale output currents of 1 ma or 0.5 ma, as shown in sfr definition 6.1 . ida0h ida0l d9 d8 d7 d6 d5 d4 d3 d2 d1 d0 input data word (d9?d0) output current ida0omd[1:0] = ?1x? output current ida0omd[1:0] = ?01? output current ida0omd[1:0] = ?00? 0x000 0 ma 0 ma 0 ma 0x001 1/1024 x 2 ma 1/1024 x 1 ma 1/1024 x 0.5 ma 0x200 512/1024 x 2 ma 512/1024 x 1 ma 512/1024 x 0.5 ma 0x3ff 1023/1024 x 2 ma 1023/1024 x 1 ma 1023/1024 x 0.5 ma
rev. 1.5 61 c8051f330/1/2/3/4/5 sfr definition 6.1. ida0cn: ida0 control sfr definition 6.2. ida0h: ida0 data word msb bit 7: ida0en: ida0 enable. 0: ida0 disabled. 1: ida0 enabled. bits 6 ? 4: ida0cm[2:0]: ida0 updat e source select bits. 000: dac output updates on timer 0 overflow. 001: dac output updates on timer 1 overflow. 010: dac output updates on timer 2 overflow. 011: dac output updates on timer 3 overflow. 100: dac output updates on rising edge of cnvstr. 101: dac output updates on falling edge of cnvstr. 110: dac output updates on any edge of cnvstr. 111: dac output updates on write to ida0h. bits 3 ? 2: unused. read = 00b. write = don?t care. bits 1:0: ida0omd[1:0]: ida0 output mode select bits. 00: 0.5 ma full-scale output current. 01: 1.0 ma full-scale output current. 1x: 2.0 ma full-scale output current. r/w r/w r/w r/w r r r/w r/w reset value ida0en ida0cm - - ida0omd 01110010 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xb9 bits 7 ? 0: ida0 data word high-order bits. bits 7 ? 0 are the most-significant bits of the 10-bit ida0 data word. r/w r/w r/w r/w r/w r/w r/w r/w reset value 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0x97
c8051f330/1/2/3/4/5 62 rev. 1.5 sfr definition 6.3. ida0l: ida0 data word lsb table 6.1. idac electrical characteristics ? 40 to +85 c, v dd = 3.0 v full-scale output current set to 2 ma unless otherwise specified. parameter conditions min typ max units static performance resolution 10 bits integral nonlinearity ? 0.5 ? lsb differential nonlinearity guaranteed monotonic ? 0.5 1 lsb output compliance range ? ? v dd ? 1.2 v output noise i out = 2 ma; r load = 100 ? ? 1 ? na/rthz offset error ? 0 ? lsb full scale error 2 ma full scale output current ? 0 ? lsb full scale error tempco ? 30 ? ppm/c v dd power supply rejection ratio ? 52 ? db output capacitance ? 2 ? pf dynamic performance output settling time to 1/2 lsb ida0h:l = 0x3ff to 0x000 ? 5 ? s startup time ? 5 ? s gain variation 1 ma full scale output current 0.5 ma full scale output current ? ? 1 1 ? ? % % power consumption power supply current (v dd supplied to idac) 2 ma full scale output current 1 ma full scale output current 0.5 ma full scale output current ? ? ? 2100 1100 600 ? ? ? a a a bits 7 ? 6: ida0 data word low-order bits. lower 2 bits of the 10-bit data word. bits 5 ? 0: unused. read = 000000b, write = don?t care. r/wr/wrrrrrrreset value ? ? ? ? ? ? 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0x96
rev. 1.5 63 c8051f330/1/2/3/4/5 7. voltage reference (c8051f330/2/4 only) the voltage reference mux on the c8 051f330/2/4 devices is configurable to use an externally connected voltage reference, the internal reference voltage generator, or the v dd power supply voltage (see figure 7.1 ). the refsl bit in the reference control regist er (ref0cn) selects th e reference source. for an external source or the internal reference, refsl should be set to ?0?. to use v dd as the reference source, refsl should be set to ?1?. the biase bit enables th e internal voltage bi as generator, which is used by the adc, temperature sensor, internal oscillators, and current dac. this bias is enabled when any of the aforementioned peripherals are enabled. the bias g enerator may be enabl ed manually by writing a ?1? to the biase bit in register ref0cn; see sfr definition 7.1 for ref0cn register details. the elec trical specifications for the voltage reference circuit are given in ta b l e 7.1 . the internal voltage reference circuit consists of a 1.2 v, temperature stable bandgap voltage reference generator and a gain-of-two output buffer amplifier. the internal voltage reference can be driven out on the vref pin by setting the refbe bit in register ref0cn to a ?1? (see sfr definition 7.1 ). the maximum load seen by the vref pin must be less than 200 a to gnd. when using the internal voltage reference, bypass capacitors of 0.1 f and 4.7 f are recommended from the vref pin to gnd. if the internal refer - ence is not used, the refbe bit should be cleared to ?0 ?. electrical specifications for the internal voltage reference are given in table 7.1 . important note about the vref pin: port pin p0.0 is used as the external vref input and as an output for the internal vref. when using eit her an external voltage reference or the internal reference circuitry, p0.0 should be configured as an analog pin, and skip ped by the digital crossbar. to configure p0.0 as an analog pin, set to ?0? bit0 in register p0mdin. to co nfigure the crossbar to skip p0.0, set bit 0 in register p0skip to ?1?. refer to section ?14. port input/output? on page 125 for complete port i/o configuration details. the tempe bit in register ref0cn enables/disables the temperature sensor. while disabled, the temperature sensor defaults to a high impedance st ate and any adc0 measurements performed on the sensor result in meaningless data. figure 7.1. voltage refere nce functional block diagram vref (to adc) to analog mux vdd vref r1 vdd external voltage reference circuit gnd temp sensor en bias generator to adc, idac, internal oscillators en iosce n 0 1 ref0cn refsl tempe biase refbe refbe internal reference en recommended bypass capacitors + 4.7 f0.1 f
c8051f330/1/2/3/4/5 64 rev. 1.5 sfr definition 7.1. ref0cn: reference control bits7?4: unused. read = 0000b; write = don?t care. bit3: refsl: voltage reference select. this bit selects the source for the internal voltage reference. 0: vref pin used as voltage reference. 1: v dd used as voltage reference. bit2: tempe: temperature sensor enable bit. 0: internal temperature sensor off. 1: internal temperature sensor on. bit1: biase: internal analog bias generator enable bit. 0: internal bias generator off. 1: internal bias generator on. bit0: refbe: internal refe rence buffer enable bit. 0: internal reference buffer disabled. 1: internal reference buffer enabled. internal voltage reference driven on the vref pin. r r r r r/w r/w r/w r/w reset value - - - - refsl tempe biase refbe 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xd1
rev. 1.5 65 c8051f330/1/2/3/4/5 table 7.1. voltage reference electrical characteristics v dd = 3.0 v; ?40 to +85 c unless otherwise specified. parameter conditions min typ max units internal reference (refbe = 1) output voltage 25 c ambient 2.38 2.44 2.50 v vref short-circuit current ? ? 10 ma vref temperature coefficient ? 15 ? ppm/c load regulation load = 0 to 200 a to agnd ? 0.5 ? ppm/a vref turn-on time 1 4.7 f tantalum, 0.1 f ceramic bypass ? 2 ? ms vref turn-on time 2 0.1 f ceramic bypass ? 20 ? s vref turn-on time 3 no bypass cap ? 10 ? s power supply rejection ? 140 ? ppm/v external reference (refbe = 0) input voltage range 0 ? v dd v input current sample rate = 200 ksps; vref = 3.0 v ? 12 ? a power specifications adc bias generator biase = ?1? or ad0en = ?1? or ioscen = ?1? ? 100 ? a reference bias generator refbe = ?1? or tempe = ?1? or ida0en = ?1? ? 40 ? a
c8051f330/1/2/3/4/5 66 rev. 1.5
rev. 1.5 67 c8051f330/1/2/3/4/5 8. comparator0 c8051f330/1/2/3/4/5 devices include an on-chip pr ogrammable voltage comparator, comparator0, shown in figure 8.1 . the comparator offers programmable response time a nd hysteresis, an analog in put multiplexer, and two outputs that are optionally avail able at the port pins: a synchronous ?latched? output (cp0), or an asyn - chronous ?raw? output (cp0a). the asynchronous cp0a signal is available even when in when the system clock is not active. this allows the comparator to operate and generate an output with the device in stop mode. when assigned to a port pin, the comparator output may be configured as open drain or push-pull (see section ?14.2. port i/o initialization? on page 129 ). comparator0 may also be used as a reset source (see section ?10.5. comparator0 reset? on page 102 ). the comparator0 inputs are select ed in the cpt0mx register ( sfr definition 8.2 ). the cmx0p1 ? cmx0p0 bits select the comparator0 positive input; the cmx0n1 ? cmx0n0 bits select the comparator0 negative input. important note about comparator inputs: the port pins selected as comparator inputs should be configured as analog inputs in their associat ed port configuration register, and configured to be skipped by the crossbar (for deta ils on port configuration, see section ?14.3. general purpose port i/o? on page 131 ). figure 8.1. comparator0 functional block diagram vdd cpt0cn reset decision tree + - crossbar q q set clr d q q set clr d (synchronizer) gnd cp0 + p0.0 p0.2 p0.4 p0.6 cp0 - p0.1 p0.3 p0.5 p0.7 cp0en cp0out cp0rif cp0fif cp0hyp1 cp0hyp0 cp0hyn1 cp0hyn0 cpt0mx cmx0n3 cmx0n2 cmx0n1 cmx0n0 cmx0p3 cmx0p2 cmx0p1 cmx0p0 cpt0md cp0rie cp0fie cp0md1 cp0md0 cp0 cp0a p1.0 p1.2 p1.4 p1.6 p1.1 p1.3 p1.5 p1.7 cp0 interrupt 0 1 0 1 cp0rif cp0fif 0 1 cp0en 0 1 ea
c8051f330/1/2/3/4/5 68 rev. 1.5 the comparator output can be polled in software, used as an interrupt source, and/or routed to a port pin. when routed to a port pin, the comp arator output is available asynch ronous or synchronous to the system clock; the asynchronous output is available even in stop mode (with no system clock active). when dis - abled, the comparator output (if assigned to a port i/o pin via the crossbar) defaults to the logic low state, and its supply current falls to less than 100 na. see section ?14.1. priority crossbar decoder? on page 127 for details on configuring comparator outputs vi a the digital crossbar. comparator inputs can be externally driven from ?0.25 v to (v dd ) + 0.25 v without damage or upset. the complete comparator elec - trical specifications are given in ta b l e 8.1 . the comparator response time may be configured in software via the cpt0md register (see sfr defini - tion 8.3 ). selecting a longer response time reduces the comparator supply current. see ta b l e 8.1 for com - plete timing and power cons umption specifications. figure 8.2. compar ator hysteresis plot the comparator hysteresis is software-programmabl e via its comparator control register cpt0cn. the user can program both the amount of hysteresis voltage (referred to the input voltage) and the positive and negative-going symmetry of this hyst eresis around the threshold voltage. the comparator hysteresis is programmed using bits3 ? 0 in the comparator co ntrol register cpt0cn (shown in sfr definition 8.1 ). the amount of negative hysteresis vo ltage is determined by the settings of the cp0hyn bits. as shown in figure 8.2 , settings of 20, 10 or 5 mv of negative hysteresis can be pro - grammed, or negative hysteresis can be disabled. in a similar way, the amount of positive hysteresis is determined by the setting the cp0hyp bits. comparator interrupts can be genera ted on both rising-e dge and falling-edge output transitions. (for inter - rupt enable and priority control, see section ?8.3. interrupt handler? on page 58 ). the cp0fif flag is set positive hysteresis voltage (programmed with cp0hyp bits) negative hysteresis voltage (programmed by cp0hyn bits) vin- vin+ inputs circuit configuration + _ cp0+ cp0- cp0 vin+ vin- out v oh positive hysteresis disabled maximum positive hysteresis negative hysteresis disabled maximum negative hysteresis output v ol
rev. 1.5 69 c8051f330/1/2/3/4/5 to logic 1 upon a comparator falling-edge occurrence , and the cp0rif flag is set to logic 1 upon the com - parator rising-edge occurrence. once set, these bits remain set until cleared by software. the comparator rising-edge interrupt mask is enabl ed by setting cp0rie to a logic 1. the comparator0 falling-edge inter - rupt mask is enabled by setting cp0fie to a logic 1. the output state of the comparator can be obtained at any time by reading the cp0out bit. the compar - ator is enabled by setting the cp0en bit to logic 1, and is disabled by clearing this bit to logic 0. note that false rising ed ges and falling edges can be detected when the comparator is fi rst powered on or if changes are made to the hy steresis or response time control bits. therefore, it is recommended that the rising-edge and falling-edge flags be explicitly cleared to logic 0 a short time after the comparator is enabled or its mode bits have been changed. this power up time is specified in ta b l e 8.1 on page 72 . sfr definition 8.1. cpt0cn: comparator0 control bit7: cp0en: comparator0 enable bit. 0: comparator0 disabled. 1: comparator0 enabled. bit6: cp0out: comparator0 output state flag. 0: voltage on cp0+ < cp0 ? . 1: voltage on cp0+ > cp0 ? . bit5: cp0rif: comparator0 rising-edge flag. must be cleared by software. 0: no comparator0 rising edge has occurr ed since this flag was last cleared. 1: comparator0 rising edge has occurred. bit4: cp0fif: comparator0 falling-edge flag. must be cleared by software. 0: no comparator0 falling-e dge has occurred since this flag was last cleared. 1: comparator0 falling-edge has occurred. bits3 ? 2: cp0hyp1 ? 0: comparator0 positive hysteresis control bits. 00: positive hysteresis disabled. 01: positive hysteresis = 5 mv. 10: positive hysteresis = 10 mv. 11: positive hysteresis = 20 mv. bits1 ? 0: cp0hyn1 ? 0: comparator0 negative hysteresis control bits. 00: negative hysteresis disabled. 01: negative hysteresis = 5 mv. 10: negative hysteresis = 10 mv. 11: negative hysteresis = 20 mv. r/w r r/w r/w r/w r/w r/w r/w reset value cp0en cp0out cp0rif cp0fif cp0hyp1 cp0hyp0 cp0hyn1 cp0hyn0 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0x9b
c8051f330/1/2/3/4/5 70 rev. 1.5 sfr definition 8.2. cpt0mx: comparator0 mux selection bits7 ? 4: cmx0n3 ? cmx0n0: comparator0 negative input mux select. these bits select which port pin is us ed as the comparator0 negative input. bits3 ? 0: cmx0p3 ? cmx0p0: comparator0 positive input mux select. these bits select which port pin is us ed as the comparator0 positive input. r/w r/w r/w r/w r/w r/w r/w r/w reset value cmx0n3 cmx0n2 cmx0n1 cmx0n0 cmx0 p3 cmx0p2 cmx0p1 cmx0p0 11111111 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0x9f cmx0n3 cmx0n2 cmx0n1 cmx0n0 negative input 0000 p0.1 0001 p0.3 0010 p0.5 0011 p0.7 0100 p1.1 0101 p1.3 0110 p1.5 0111 p1.7 1xxx none cmx0p3 cmx0p2 cmx0p1 cmx0p0 positive input 0000 p0.0 0001 p0.2 0010 p0.4 0011 p0.6 0100 p1.0 0101 p1.2 0110 p1.4 0111 p1.6 1xxx none
rev. 1.5 71 c8051f330/1/2/3/4/5 sfr definition 8.3. cpt0md: comparator 0 mode selection bits7 ? 6: unused. read = 00b, write = don?t care. bit5: cp0rie: comparator0 rising-edge interrupt enable. 0: comparator0 rising-edge interrupt disabled. 1: comparator0 rising-edge interrupt enabled. bit4: cp0fie: comparator0 falling-edge interrupt enable. 0: comparator0 falling-edge interrupt disabled. 1: comparator0 falling-edge interrupt enabled. bits3 ? 2: unused. read = 00b, write = don?t care. bits1 ? 0: cp0md1 ? cp0md0: comparator0 mode select these bits select the response time for comparator0. r r r/w r/w r r r/w r/w reset value - - cp0rie cp0fie - - cp0md1 cp0md0 00000010 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0x9d mode cp0md1 cp0md0 cp0 response time (typ) 000 100 ns 101 175 ns 210 320 ns 3 1 1 1050 ns
c8051f330/1/2/3/4/5 72 rev. 1.5 table 8.1. comparator electrical characteristics v dd = 3.0 v, ?40 to +85 c unless otherwise noted. parameter conditions min typ max units response time: mode 0, vcm * = 1.5 v cp0+ ? cp0? = 100 mv ? 100 ? ns cp0+ ? cp0? = ?100 mv ? 250 ? ns response time: mode 1, vcm * = 1.5 v cp0+ ? cp0? = 100 mv ? 175 ? ns cp0+ ? cp0? = ?100 mv ? 500 ? ns response time: mode 2, vcm * = 1.5 v cp0+ ? cp0? = 100 mv ? 320 ? ns cp0+ ? cp0? = ?100 mv ? 1100 ? ns response time: mode 3, vcm * = 1.5 v cp0+ ? cp0? = 100 mv ? 1050 ? ns cp0+ ? cp0? = ?100 mv ? 5200 ? ns common-mode rejection ratio ? 1.5 4 mv/v positive hysteresis 1 cp0hyp1?0 = 00 ? 0 1 mv positive hysteresis 2 cp0hyp1?0 = 01 2 5 10 mv positive hysteresis 3 cp0hyp1?0 = 10 7 10 20 mv positive hysteresis 4 cp0hyp1?0 = 11 15 20 30 mv negative hysteresis 1 cp0hyn1?0 = 00 0 1 mv negative hysteresis 2 cp0hyn1?0 = 01 2 5 10 mv negative hysteresis 3 cp0hyn1?0 = 10 7 10 20 mv negative hysteresis 4 cp0hyn1?0 = 11 15 20 30 mv inverting or non- inverting input voltage range ?0.25 ? v dd + 0.25 v input capacitance ? 4 ? pf input bias current ? 0.001 ? na input offset voltage ?5 ? +5 mv power supply power supply rejection ? 0.1 ? mv/v power-up time ? 10 ? s supply current at dc mode 0 ? 7.6 ? a mode 1 ? 3.2 ? a mode 2 ? 1.3 ? a mode 3 ? 0.4 ? a *note: vcm is the common-mode voltage on cp0+ and cp0?.
rev. 1.5 73 c8051f330/1/2/3/4/5 9. cip-51 microcontroller the mcu system controller core is the cip-51 microcon troller. the cip-51 is fully compatible with the mcs-51? instruction set; standard 803x/805x assemble rs and compilers can be used to develop soft - ware. the mcu family has a superset of all the peripherals included with a standard 8051. included are four 16-bit counter/timers (see description in section 18 ), an enhanced full-duplex uart (see description in section 16 ), an enhanced spi (see description in section 17 ), 256 bytes of internal ram, 128 byte special function register (sfr) address space ( section 9.2.6 ), and 17 port i/o (see description in sec - tion 14 ). the cip-51 also includes on-chip debug hardware (see description in section 20 ), and interfaces directly with the analog and digi tal subsystems providing a complete data acquisition or control-system solution in a single integrated circuit. the cip-51 microcontroller core implements the standard 8051 organization and peripherals as well as additional custom peripherals and func tions to extend its capability (see figure 9.1 for a block diagram). the cip-51 includes the following features: performance the cip-51 employs a pipelined architecture that grea tly increases its instruction throughput over the stan - dard 8051 architecture. in a standar d 8051, all instructions except for mul and div take 12 or 24 system clock cycles to execute, and usually have a maximum system clock of 12 mhz. by contrast, the cip-51 core executes 70% of its instructions in one or tw o system clock cycles, with no instructions taking more than eight system clock cycles. figure 9.1. cip-51 block diagram - fully compatible wit h mcs-51 instruction set - 25 mips peak throughput with 25 mhz clock - 0 to 25 mhz clock frequency - 256 bytes of internal ram -17 port i/o - extended interrupt handler - reset input - power management modes data bus tmp1 tmp2 prgm. address reg. pc incrementer alu psw data bus data bus memory interface mem_address d8 pipeline buffer data pointer interrupt interface system_irqs emulation_irq mem_control control logic a16 program counter (pc) stop clock reset idle power control register data bus sfr bus interface sfr_address sfr_control sfr_write_data sfr_read_data d8 d8 b register d8 d8 accumulator d8 d8 d8 d8 d8 d8 d8 d8 mem_write_data mem_read_data d8 sram address register sram (256 x 8) d8 stack pointer d8
c8051f330/1/2/3/4/5 74 rev. 1.5 with the cip-51's maximum system clock at 25 mhz, it has a peak throughput of 25 mips. the cip-51 has a total of 109 instructions. the table below shows the to tal number of instructions that require each execu - tion time. programming and debugging support in-system programming of the flash program memory and communication with on-chip debug support logic is accomplished via the silicon labs 2-wire de velopment interface (c2). note that the re-program - mable flash can also be read and changed a single by te at a time by the application software using the movc and movx instructions. this feature allows program memory to be used for non-volatile data stor - age as well as updating program code under software control. the on-chip debug support logic facilitates full speed in-circuit debugging, a llowing the setting of hardware breakpoints, starting, stopping and single stepping th rough program execution (including interrupt service routines), examination of the program's call stack, a nd reading/writing the conten ts of registers and mem - ory. this method of on-chip debugging is completely non-intrusive, requiring no ram, stack, timers, or other on-chip resources. c2 details can be found in section ?20. c2 interface? on page 211 . the cip-51 is support ed by development tools from silicon labs and third party vendors. silicon labs pro - vides an integrated development environment (ide) in cluding editor, macro assembler, debugger and pro - grammer. the ide's debugger and programmer interface to the cip-51 via the c2 interface to provide fast and efficient in-system device programming and deb ugging. third party macro assemblers and c compil - ers are also available. 9.1. instruction set the instruction set of the cip-51 system controller is fully compatible with the standard mcs-51? instruc - tion set. standard 8051 development tools can be used to develop software for the cip-51. all cip-51 instructions are the binary and fu nctional equivalent of their mcs-51? counterparts, including opcodes, addressing modes and effect on psw flags. however, in struction timing is different than that of the stan - dard 8051. 9.1.1. instruction and cpu timing in many 8051 implementations, a distinction is ma de between machine cycles and clock cycles, with machine cycles varying from 2 to 12 clock cycles in length. however, the cip-51 implementation is based solely on clock cycle timing. all instructio n timings are specified in terms of clock cycles. due to the pipelined architecture of the cip-51, most instructions execute in the same number of clock cycles as there are program bytes in the instruction. conditional branch instruct ions take one less clock cycle to complete when the branch is not taken as opposed to when the branch is taken. table 9.1 is the cip-51 instruction set summary, which includes the mnemonic, number of bytes, and number of clock cycles for each instruction. 9.1.2. movx instruction and program memory the movx instruction is typically used to access external data memory (note: the c8051f330/1/2/3/4/5 does not support off-chip data or program memory). in the cip-51, the movx instruction can be used to access on-chip xram or on-chip program memory space implemented as re-programmable flash mem - ory. the flash access feature prov ides a mechanism for the cip-51 to update program code and use the clocks to execute 1 2 2/3 3 3/4 4 4/5 5 8 number of instructions 26 50 5 14 7 3 1 2 1
rev. 1.5 75 c8051f330/1/2/3/4/5 program memory space for non-volatile data storage. refer to section ?11. flash memory? on page 105 for further details. table 9.1. cip-51 instruction set summary mnemonic description bytes clock cycles arithmetic operations add a, rn add register to a 1 1 add a, direct add direct byte to a 2 2 add a, @ri add indirect ram to a 1 2 add a, #data add immediate to a 2 2 addc a, rn add register to a with carry 1 1 addc a, direct add direct byte to a with carry 2 2 addc a, @ri add indirect ram to a with carry 1 2 addc a, #data add immediate to a with carry 2 2 subb a, rn subtract register from a with borrow 1 1 subb a, direct subtract direct byte from a with borrow 2 2 subb a, @ri subtract indirect ram from a with borrow 1 2 subb a, #data subtract immediate from a with borrow 2 2 inc a increment a 1 1 inc rn increment register 1 1 inc direct increment direct byte 2 2 inc @ri increment indirect ram 1 2 dec a decrement a 1 1 dec rn decrement register 1 1 dec direct decrement direct byte 2 2 dec @ri decrement indirect ram 1 2 inc dptr increment data pointer 1 1 mul ab multiply a and b 1 4 div ab divide a by b 1 8 da a decimal adjust a 1 1 logical operations anl a, rn and register to a 1 1 anl a, direct and direct byte to a 2 2 anl a, @ri and indirect ram to a 1 2 anl a, #data and immediate to a 2 2 anl direct, a and a to direct byte 2 2 anl direct, #data and immediate to direct byte 3 3 orl a, rn or register to a 1 1 orl a, direct or direct byte to a 2 2 orl a, @ri or indirect ram to a 1 2 orl a, #data or immediate to a 2 2 orl direct, a or a to direct byte 2 2 orl direct, #data or immediate to direct byte 3 3 xrl a, rn exclusive-or register to a 1 1 xrl a, direct exclusive-or direct byte to a 2 2 xrl a, @ri exclusive-or indirect ram to a 1 2
c8051f330/1/2/3/4/5 76 rev. 1.5 xrl a, #data exclusive-or immediate to a 2 2 xrl direct, a exclusive-or a to direct byte 2 2 xrl direct, #data exclusive-or immediate to direct byte 3 3 clr a clear a 1 1 cpl a complement a 1 1 rl a rotate a left 1 1 rlc a rotate a left through carry 1 1 rr a rotate a right 1 1 rrc a rotate a right through carry 1 1 swap a swap nibbles of a 1 1 data transfer mov a, rn move register to a 1 1 mov a, direct move direct byte to a 2 2 mov a, @ri move indirect ram to a 1 2 mov a, #data move immediate to a 2 2 mov rn, a move a to register 1 1 mov rn, direct move direct byte to register 2 2 mov rn, #data move immediate to register 2 2 mov direct, a move a to direct byte 2 2 mov direct, rn move register to direct byte 2 2 mov direct, direct move direct byte to direct byte 3 3 mov direct, @ri move indirect ram to direct byte 2 2 mov direct, #data move immediate to direct byte 3 3 mov @ri, a move a to indirect ram 1 2 mov @ri, direct move direct byte to indirect ram 2 2 mov @ri, #data move immediate to indirect ram 2 2 mov dptr, #data16 load dptr with 16-bit constant 3 3 movc a, @a+dptr move code byte relative dptr to a 1 3 movc a, @a+pc move code byte relative pc to a 1 3 movx a, @ri move external data (8-bit address) to a 1 3 movx @ri, a move a to external data (8-bit address) 1 3 movx a, @dptr move external data (16-bit address) to a 1 3 movx @dptr, a move a to external data (16-bit address) 1 3 push direct push direct byte onto stack 2 2 pop direct pop direct byte from stack 2 2 xch a, rn exchange register with a 1 1 xch a, direct exchange direct byte with a 2 2 xch a, @ri exchange indirect ram with a 1 2 xchd a, @ri exchange low nibble of indirect ram with a 1 2 boolean manipulation clr c clear carry 1 1 clr bit clear direct bit 2 2 setb c set carry 1 1 setb bit set direct bit 2 2 table 9.1. cip-51 instructi on set summary (continued) mnemonic description bytes clock cycles
rev. 1.5 77 c8051f330/1/2/3/4/5 cpl c complement carry 1 1 cpl bit complement direct bit 2 2 anl c, bit and direct bit to carry 2 2 anl c, /bit and complement of direct bit to carry 2 2 orl c, bit or direct bit to carry 2 2 orl c, /bit or complement of direct bit to carry 2 2 mov c, bit move direct bit to carry 2 2 mov bit, c move carry to direct bit 2 2 jc rel jump if carry is set 2 2/3 jnc rel jump if carry is not set 2 2/3 jb bit, rel jump if direct bit is set 3 3/4 jnb bit, rel jump if direct bit is not set 3 3/4 jbc bit, rel jump if direct bit is set and clear bit 3 3/4 program branching acall addr11 absolute subroutine call 2 3 lcall addr16 long subroutine call 3 4 ret return from subroutine 1 5 reti return from interrupt 1 5 ajmp addr11 absolute jump 2 3 ljmp addr16 long jump 3 4 sjmp rel short jump (relative address) 2 3 jmp @a+dptr jump indirect relative to dptr 1 3 jz rel jump if a equals zero 2 2/3 jnz rel jump if a does not equal zero 2 2/3 cjne a, direct, rel compare direct byte to a and jump if not equal 3 3/4 cjne a, #data, rel compare immediate to a and jump if not equal 3 3/4 cjne rn, #data, rel compare immediate to register and jump if not equal 3 3/4 cjne @ri, #data, rel compare immediate to indirect and jump if not equal 3 4/5 djnz rn, rel decrement register and jump if not zero 2 2/3 djnz direct, rel decrement direct byte and jump if not zero 3 3/4 nop no operation 1 1 table 9.1. cip-51 instructi on set summary (continued) mnemonic description bytes clock cycles
c8051f330/1/2/3/4/5 78 rev. 1.5 9.2. memory organization the memory organization of the cip-51 system controller is similar to that of a standard 8051. there are two separate memory spaces: program memory and data memory. program and data memory share the same address space but are accessed via different in struction types. the cip-51 memory organization is shown in figure 9.2 notes on registers, operands and addressing modes: rn - register r0?r7 of the curr ently selected register bank. @ri - data ram location addressed indirectly through r0 or r1. rel - 8-bit, signed (two?s complement) offset relative to the first byte of the following instruction. used by sjmp and all conditional jumps. direct - 8-bit internal data location?s address. this could be a direct-access data ram location (0x00? 0x7f) or an sfr (0x80?0xff). #data - 8-bit constant #data16 - 16-bit constant bit - direct-accessed bit in data ram or sfr addr11 - 11-bit destination address used by acall and ajmp. the destination mu st be within the same 2 kb page of program memory as the first byte of the following instruction. addr16 - 16-bit destination address used by lcall a nd ljmp. the destination may be anywhere within the 8 kb program memory space. there is one unused opcode (0xa5) that performs the same function as nop. all mnemonics copyrighted ? intel corporation 1980.
rev. 1.5 79 c8051f330/1/2/3/4/5 figure 9.2. memory map 9.2.1. program memory the cip-51 core has a 64 kb program memory space. the c8051f3 30/1 implements 8 kb of this program memory space as in-system, re-pro grammable flash memory, organize d in a contiguous block from addresses 0x0000 to 0x1dff. addresses above 0x1dff are reserved on the 8 kb devices. the c8051f332/3 and c8051f334/5 implement, in contiguous blocks, 2 and 4 kb, from addresses 0x0000 to 0x07ff or 0x0000 to 0x0fff, respectively. addresses above 0x0800 and 0x1000 are reserved on the 2 and 4 kb devices, respectively. program memory is normally assumed to be read-only . however, the cip-51 can write to program memory by setting the program store write enable bit (psctl.0) and using the movx write instruction. this fea - ture provides a mechanism for the cip-51 to updat e program code and use the program memory space for non-volatile data storage. refer to section ?11. flash memory? on page 105 for further details. c8051f330/1 program/data memory (flash) (direct and indirect addressing) 0x00 0x7f upper 128 ram (indirect addressing only) 0x80 0xff special function register's (direct addressing only) data memory (ram) general purpose registers 0x1f 0x20 0x2f bit addressable lower 128 ram (direct and indirect addressing) 0x30 internal data address space external data address space xram - 512 bytes (accessable using movx instruction) 0x0000 0x01ff same 512 bytes as from 0x0000 to 0x01ff, wrapped on 512-byte boundaries 0x0200 0xffff 8 k flash (in-system programmable in 512 byte sectors) 0x0000 reserved 0x1e00 0x1dff c8051f332/3 program/data memory (flash) 4 k flash (in-system programmable in 512 byte sectors) 0x0000 reserved 0x1000 0x0fff c8051f334/5 program/data memory (flash) 2 k flash (in-system programmable in 512 byte sectors) 0x0000 reserved 0x800 0x7ff
c8051f330/1/2/3/4/5 80 rev. 1.5 9.2.2. data memory the cip-51 includes 256 bytes of internal ram mapped into the data memory space from 0x00 through 0xff. the lower 128 bytes of data memory are used for gener al purpose registers and scratch pad mem - ory. either direct or indirect addressing may be used to access the lower 128 bytes of data memory. loca - tions 0x00 through 0x1f are addressable as four banks of general purpose register s, each bank consisting of eight byte-wide registers. the next 16 bytes, locations 0x20 through 0x2f, may either be addressed as bytes or as 128 bit locations accessible with the direct addressing mode. the upper 128 bytes of data memory are accessible only by i ndirect addressing. this region occupies the same address space as the special function regist ers (sfr) but is physically separate from the sfr space. the addressing mode used by an instructio n when accessing locations above 0x7f determines whether the cpu accesses the upper 128 bytes of data memory space or th e sfrs. instructions that use direct addressing will access the sfr space. instructions using indirect addressing above 0x7f access the upper 128 bytes of data memory. figure 9.2 illustrates the data memory organization of the cip-51. 9.2.3. general purpose registers the lower 32 bytes of data memory, locations 0x00 through 0x1f, may be addressed as four banks of gen - eral-purpose registers. each bank consists of eigh t byte-wide registers designated r0 through r7. only one of these banks may be enabled at a time. two bi ts in the program status word, rs0 (psw.3) and rs1 (psw.4), select the active register bank (see description of the psw in sfr definition 9.4 ). this allows fast context switching when entering subroutines and in terrupt service routines. indirect addressing modes use registers r0 and r1 as index registers. 9.2.4. bit addressable locations in addition to direct access to data memory organized as bytes, the sixteen data memory locations at 0x20 through 0x2f are also accessible as 128 individually addressable bits. each bit has a bit address from 0x00 to 0x7f. bit 0 of the byte at 0x20 has bit address 0x00 while bit7 of the byte at 0x20 has bit address 0x07. bit 7 of the byte at 0x2f has bit address 0x7f. a bit access is distinguished from a full byte access by the type of instruction used (bit source or destinat ion operands as opposed to a byte source or destina - tion). the mcs-51? assembly language allows an alternate notation for bit addressing of the form xx.b where xx is the byte address and b is the bit position within the byte. for example, the instruction: mov c, 22.3h moves the boolean value at 0x13 (bit 3 of the byte at location 0x22) into the carry flag. 9.2.5. stack a programmer's stack can be located anywhere in the 256-byte data memory. the stack area is desig - nated using the stack pointer (sp, 0x81) sfr. the sp will poin t to the last location used. the next value pushed on the stack is placed at sp +1 and then sp is incremented. a re set initializes the stack pointer to location 0x07. therefore, the first value pushed on the st ack is placed at location 0x08, which is also the first register (r0) of register bank 1. thus, if more than one register bank is to be used, the sp should be initialized to a location in the data memory not being used for data storage. the stack depth can extend up to 256 bytes.
rev. 1.5 81 c8051f330/1/2/3/4/5 9.2.6. special function registers the direct-access data memory locations from 0x80 to 0xff constitute the sp ecial function registers (sfrs). the sfrs provide control and data exchang e with the cip-51's resources and peripherals. the cip-51 duplicates the sfrs found in a typical 805 1 implementation as well as implementing additional sfrs used to configure and access the sub-systems uni que to the mcu. this allows the addition of new functionality while retain ing compatibility with the mc s-51? instruction set. ta b l e 9.2 lists the sfrs imple - mented in the cip-51 system controller. the sfr registers are accessed anytime the direct ad dressing mode is used to access memory locations from 0x80 to 0xff. sfrs with addresses ending in 0x 0 or 0x8 (e.g. p0, tcon, scon0, ie, etc.) are bit- addressable as well as byte-addressable. all othe r sfrs are byte-addressable only. unoccupied addresses in the sfr space are rese rved for future use. accessing t hese areas will have an indeterminate effect and should be avoided. refer to the corres ponding pages of the data sheet, as indicated in ta b l e 9.3 , for a detailed description of each register. table 9.2. special function regist er (sfr) memory map f8 spi0cn pca0l pca0h pca0cpl0 pca0cph0 vdm0cn f0 b p0mdin p1mdin eip1 e8 adc0cn pca0cpl1 pca0cph1 pca0cpl2 pca0cph2 rstsrc e0 acc xbr0 xbr1 osclcn it01cf eie1 d8 pca0cn pca0md pca0cpm0 pca0cpm1 pca0cpm2 d0 psw ref0cn p0skip p1skip c8 tmr2cn tmr2rll tmr2rlh tmr2l tmr2h c0 smb0cn smb0cf smb0dat adc0gtl adc0gth adc0ltl adc0lth b8 ip ida0cn amx0n amx0p adc0cf adc0l adc0h b0 oscxcn oscicn oscicl flscl flkey a8 ie clksel emi0cn a0 p2 spi0cfg spi0ckr spi0dat p0mdout p1mdout p2mdout 98 scon0 sbuf0 cpt0cn cpt0md cpt0mx 90 p1 tmr3cn tmr3rll tmr3rlh tmr3l tmr3h ida0l ida0h 88 tcon tmod tl0 tl1 th0 th1 ckcon psctl 80 p0 sp dpl dph pcon 0(8) 1(9) 2(a) 3(b) 4(c) 5(d) 6(e) 7(f) (bit addressable)
c8051f330/1/2/3/4/5 82 rev. 1.5 table 9.3. special function registers sfrs are listed in alphabetical order. all undefined sfr locations are reserved register address description page acc 0xe0 accumulator 87 adc0cf 0xbc adc0 configuration 51 adc0cn 0xe8 adc0 control 52 adc0gth 0xc4 adc0 greater-than compare high 53 adc0gtl 0xc3 adc0 greater-than compare low 53 adc0h 0xbe adc0 high 51 adc0l 0xbd adc0 low 51 adc0lth 0xc6 adc0 less-than compare word high 54 adc0ltl 0xc5 adc0 less-than compare word low 54 amx0n 0xba amux0 negative channel select 50 amx0p 0xbb amux0 positive channel select 49 b 0xf0 b register 87 ckcon 0x8e clock control 185 clksel 0xa9 clock select 123 cpt0cn 0x9b comparator0 control 69 cpt0md 0x9d comparator0 mode selection 71 cpt0mx 0x9f comparator0 mux selection 70 dph 0x83 data pointer high 85 dpl 0x82 data pointer low 85 eie1 0xe6 extended interrupt enable 1 93 eip1 0xf6 extended interrupt priority 1 94 emi0cn 0xaa external memory interface control 113 flkey 0xb7 flash lock and key 111 flscl 0xb6 flash scale 111 ida0cn 0xb9 current mode dac0 control 61 ida0h 0x97 current mode dac0 high 61 ida0l 0x96 current mode dac0 low 62 ie 0xa8 interrupt enable 91 ip 0xb8 interrupt priority 92 it01cf 0xe4 int0/int1 configuration 95 oscicl 0xb3 internal oscillator calibration 116 oscicn 0xb2 internal oscillator control 116 osclcn 0xe3 low-frequency o scillator control 117
rev. 1.5 83 c8051f330/1/2/3/4/5 oscxcn 0xb1 external oscillator control 119 p0 0x80 port 0 latch 132 p0mdin 0xf1 port 0 input mode configuration 132 p0mdout 0xa4 port 0 output mode configuration 133 p0skip 0xd4 port 0 skip 133 p1 0x90 port 1 latch 133 p1mdin 0xf2 port 1 input mode configuration 134 p1mdout 0xa5 port 1 output mode configuration 134 p1skip 0xd5 port 1 skip 134 p2 0xa0 port 2 latch 135 p2mdout 0xa6 port 2 output mode configuration 135 pca0cn 0xd8 pca control 207 pca0cph0 0xfc pca capture 0 high 210 pca0cph1 0xea pca capture 1 high 210 pca0cph2 0xec pca capture 2 high 210 pca0cpl0 0xfb pca capture 0 low 210 pca0cpl1 0xe9 pca capture 1 low 210 pca0cpl2 0xeb pca capture 2 low 210 pca0cpm0 0xda pca module 0 mode register 209 pca0cpm1 0xdb pca module 1 mode register 209 pca0cpm2 0xdc pca module 2 mode register 209 pca0h 0xfa pca counter high 210 pca0l 0xf9 pca counter low 210 pca0md 0xd9 pca mode 208 pcon 0x87 power control 97 psctl 0x8f program store r/w control 110 psw 0xd0 program status word 86 ref0cn 0xd1 voltage reference control 64 rstsrc 0xef reset source configuration/status 103 sbuf0 0x99 uart0 data buffer 161 scon0 0x98 uart0 control 160 smb0cf 0xc1 smbus configuration 144 smb0cn 0xc0 smbus control 146 smb0dat 0xc2 smbus data 148 table 9.3. special functi on registers (continued) sfrs are listed in alphabetical order. all undefined sfr locations are reserved register address description page
c8051f330/1/2/3/4/5 84 rev. 1.5 sp 0x81 stack pointer 85 spi0cfg 0xa1 spi configuration 172 spi0ckr 0xa2 spi clock rate control 174 spi0cn 0xf8 spi control 173 spi0dat 0xa3 spi data 174 tcon 0x88 timer/counter control 183 th0 0x8c timer/counter 0 high 186 th1 0x8d timer/counter 1 high 186 tl0 0x8a timer/counter 0 low 186 tl1 0x8b timer/counter 1 low 186 tmod 0x89 timer/counter mode 184 tmr2cn 0xc8 timer/counter 2 control 189 tmr2h 0xcd timer/counter 2 high 190 tmr2l 0xcc timer/counter 2 low 190 tmr2rlh 0xcb timer/counter 2 reload high 190 tmr2rll 0xca timer/counter 2 reload low 190 tmr3cn 0x91 timer/counter 3control 193 tmr3h 0x95 timer/counter 3 high 194 tmr3l 0x94 timer/counter 3low 194 tmr3rlh 0x93 timer/counter 3 reload high 194 tmr3rll 0x92 timer/counter 3 reload low 194 vdm0cn 0xff v dd monitor control 101 xbr0 0xe1 port i/o crossbar control 0 130 xbr1 0xe2 port i/o crossbar control 1 131 table 9.3. special functi on registers (continued) sfrs are listed in alphabetical order. all undefined sfr locations are reserved register address description page
rev. 1.5 85 c8051f330/1/2/3/4/5 9.2.7. register descriptions following are descriptions of sfrs related to the operati on of the cip-51 system controller. reserved bits should not be set to logic l. future product versions may use these bits to implement new features in which case the reset value of the bit will be logic 0, selecting the feature's default state. detailed descriptions of the remaining sfrs are included in the sections of the datasheet associated with their corresponding sys - tem function. sfr definition 9.1. dpl: data pointer low byte sfr definition 9.2. dph: data pointer high byte sfr definition 9.3. sp: stack pointer bits7?0: dpl: data pointer low. the dpl register is the low byte of the 16-b it dptr. dptr is used to access indirectly addressed flash memory or xram. r/w r/w r/w r/w r/w r/w r/w r/w reset value 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0x82 bits7?0: dph: data pointer high. the dph register is the high byte of the 16-b it dptr. dptr is used to access indirectly addressed flash memory or xram. r/w r/w r/w r/w r/w r/w r/w r/w reset value 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0x83 bits7?0: sp: stack pointer. the stack pointer holds the location of the top of the stack. the stack pointer is incremented before every push operation. the sp r egister defaults to 0x07 after reset. r/w r/w r/w r/w r/w r/w r/w r/w reset value 00000111 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0x81
c8051f330/1/2/3/4/5 86 rev. 1.5 sfr definition 9.4. psw: program status word bit7: cy: carry flag. this bit is set when the last arithmetic operat ion resulted in a carry (addition) or a borrow (subtraction). it is cleared to logi c 0 by all other arithmetic operations. bit6: ac: auxiliary carry flag this bit is set when the last arithmetic operati on resulted in a carry into (addition) or a borrow from (subtraction) the high order nibble. it is cleared to logic 0 by all other arithmetic opera- tions. bit5: f0: user flag 0. this is a bit-addressable, general purpose flag for use under software control. bits4?3: rs1?rs0: register bank select. these bits select which register ban k is used during register accesses. bit2: ov: overflow flag. this bit is set to 1 under the following circumstances: ? an add, addc, or subb instructi on causes a sign-change overflow. ? a mul instruction results in an overflow (result is greater than 255). ? a div instruction causes a divide-by-zero condition. the ov bit is cleared to 0 by the add, addc, subb, mul, and div inst ructions in all other cases. bit1: f1: user flag 1. this is a bit-addressable, general purpose flag for use under software control. bit0: parity: parity flag. this bit is set to logic 1 if the sum of the eight bits in the accumulator is odd and cleared if the sum is even. r/wr/wr/wr/wr/wr/wr/w rreset value cy ac f0 rs1 rs0 ov f1 parity 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: (bit addressable) 0xd0 rs1 rs0 register bank address 0 0 0 0x00?0x07 0 1 1 0x08?0x0f 1 0 2 0x10?0x17 1 1 3 0x18?0x1f
rev. 1.5 87 c8051f330/1/2/3/4/5 sfr definition 9.5. acc: accumulator sfr definition 9.6. b: b register 9.3. interrupt handler the cip-51 includes an extended interrupt system supporting a total of 13 interrupt sources with two prior - ity levels. the allocation of interrupt sources between on-chip periph erals and external inputs pins varies according to the specific version of the device. each interrupt source has one or more associated interrupt- pending flag(s) located in an sfr. when a peripheral or external source meets a valid interrupt condition, the associated interrupt-pend ing flag is set to logic 1. if interrupts are enabled for the source, an interrupt req uest is generated when the interrupt-pending flag is set. as soon as execution of the current instructio n is complete, the cpu generates an lcall to a prede - termined address to begin execution of an interrupt se rvice routine (isr). each isr must end with an reti instruction, which returns program execution to the next instruction that would have been executed if the interrupt request had not occurred. if interrupts are not enabled, the interrupt-pending flag is ignored by the hardware and program execution continues as normal . (the interrupt-pending flag is set to logic 1 regard - less of the interrupt's enable/disable state.) each interrupt source can be individually enabled or disabled through the use of an associated interrupt enable bit in an sfr (ie?eie1). ho wever, interrupts must first be globally enabled by setting the ea bit (ie.7) to logic 1 before the individual interrupt enables are re cognized. setting the ea bit to logic 0 disables all interrupt sources regardless of the individual interrupt-enable settings. note: any instruction that clears the ea bit should be immediately followed by an instruction that has two or more opcode bytes. for example: // in 'c': ea = 0; // clear ea bit. bits7?0: acc: accumulator. this register is the accumulator for arithmetic operations. r/w r/w r/w r/w r/w r/w r/w r/w reset value acc.7 acc.6 acc.5 acc.4 acc.3 acc.2 acc.1 acc.0 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: (bit addressable) 0xe0 bits7?0: b: b register. this register serves as a second accumu lator for certain arithmetic operations. r/w r/w r/w r/w r/w r/w r/w r/w reset value b.7 b.6 b.5 b.4 b.3 b.2 b.1 b.0 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: (bit addressable) 0xf0
c8051f330/1/2/3/4/5 88 rev. 1.5 ea = 0; // this is a dummy instruction with two-byte opcode. ; in assembly: clr ea ; clear ea bit. clr ea ; this is a dummy instruction with two-byte opcode. if an interrupt is posted during the execution phase of a "clr ea" opcode (or an y instruction which clears the ea bit), and the instruction is followed by a single-cycle instruction, the interrupt may be taken. how - ever, a read of the ea bit will return a '0' inside the inte rrupt service routin e. when the "clr ea" opcode is followed by a multi-cycle instruct ion, the interrupt will not be taken. some interrupt-pending flags are automatically cleare d by the hardware when the cpu vectors to the isr. however, most are not cleared by the hardware and must be cleared by software before returning from the isr. if an interrupt-pending flag remains set after the cpu completes the return-from-interrupt (reti) instruction, a new interr upt request will be gen erated immediately and the cpu will re-enter the isr after the completion of the next instruction. 9.3.1. mcu interrupt sources and vectors the mcus support 13 interrupt sources. software can simulate an interrupt by setting any interrupt-pend - ing flag to logic 1. if interrupts are enab led for the flag, an in terrupt reque st will be generat ed and the cpu will vector to the isr address associ ated with the interrup t-pending flag. mcu inte rrupt sources, associ - ated vector addresses, priority order and control bits are summarized in ta b l e 9.4 on page 90 . refer to the datasheet section associated with a particular on-chip peripheral for information regarding valid interrupt conditions for the peripheral and the behavior of its interrupt-pending flag(s).
rev. 1.5 89 c8051f330/1/2/3/4/5 9.3.2. external interrupts the /int0 and /int1 external interrupt sources are confi gurable as active high or low, edge or level sensi - tive. the in0pl (/int0 polarity) and in1pl (/int1 polarity ) bits in the it01cf register select active high or active low; the it0 and it1 bits in tcon ( section ?18.1. timer 0 and timer 1? on page 179 ) select level or edge sensitive. the table below lists the possible configurations. /int0 and /int1 are assigned to port pins as defined in the it01cf register (see sfr definition 9.11 ). note that /int0 and /int0 port pin assignments are independent of any crossbar assignments. /int0 and /int1 will monitor their assigned port pins without disturbing th e peripheral that was assigned the port pin via the crossbar. to assign a port pin only to /int 0 and/or /int1, configure the crossbar to skip the selected pin(s). this is accomplished by setti ng the associated bit in register xbr0 (see section ?14.1. priority crossbar decoder? on page 127 for complete details on configuring the crossbar). ie0 (tcon.1) and ie1 (tcon.3) serve as the interr upt-pending flags for the /int0 and /int1 external interrupts, respectively. if an /int0 or /int1 external interrupt is configured as edge-sensitive, the corre - sponding interrupt-pending flag is automatically clear ed by the hardware when the cpu vectors to the isr. when configured as level sensitive, the interrupt-pendi ng flag remains logic 1 while the input is active as defined by the corresponding polarity bit (in0pl or in 1pl); the flag remains logi c 0 while the input is inac - tive. the external interrupt source must hold the input active until the interrupt request is recognized. it must then deactivate the interrup t request before execution of the isr completes or another interrupt request will be generated. 9.3.3. interrupt priorities each interrupt source can be individually programmed to one of two priority levels: low or high. a low prior - ity interrupt service routine can be pree mpted by a high priority interrupt. a high priority interrupt cannot be preempted. each interrupt has an associated interrupt priority bit in an sfr (ip or eip1) used to configure its priority level. low priority is th e default. if two interrupts are recognized simultaneously, the interrupt with the higher priority is serviced first. if both interrupts have the same priority level, a fixed priority order is used to arbitrate, given in ta b l e 9.4 . 9.3.4. interrupt latency interrupt response time depends on the state of the cpu when the interrupt occurs. pending interrupts are sampled and priority decoded each sys tem clock cycle. therefore, the fa stest possible response time is 5 system clock cycles: 1 clock cycle to detect the interrupt and 4 clock cycles to complete the lcall to the isr. if an interrupt is pending when a reti is execut ed, a single instruction is executed before an lcall is made to service the pending interrupt. therefore, the maximum response time for an interrupt (when no other interrupt is currently being serviced or the new in terrupt is of greater priority) occurs when the cpu is performing an reti instruct ion followed by a div as the next instructio n. in this case, th e response time is 18 system clock cycles: 1 clock cycle to detect the interrupt, 5 clock cycles to execute the reti, 8 clock cycles to complete the div instruction and 4 clock cycles to execute the lcall to the isr. if the cpu is executing an isr for an interr upt with equal or higher pr iority, the new interrupt will not be serviced until the current isr completes, including the reti and following instruction. it0 in0pl /int0 interrupt it1 in1pl /int1 interrupt 10 active low, edge sensitive 10 active low, edge sensitive 11 active high, edge sensitive 11 active high, edge sensitive 00 active low, level sensitive 00 active low, level sensitive 01 active high, level sensitive 01 active high, level sensitive
c8051f330/1/2/3/4/5 90 rev. 1.5 table 9.4. interrupt summary interrupt source interrupt vector priority order pending flag bit addressable? cleared by hw? enable flag priority control reset 0x0000 to p none n/a n/a always enabled always highest external interrupt 0 (/int0) 0x0003 0 ie0 (tcon.1) y y ex0 (ie.0) px0 (ip.0) timer 0 overflow 0x000b 1 tf0 (tcon.5) y y et0 (ie.1) pt0 (ip.1) external interrupt 1 (/int1) 0x0013 2 ie1 (tcon.3) y y ex1 (ie.2) px1 (ip.2) timer 1 overflow 0x001b 3 tf1 (tcon.7) y y et1 (ie.3) pt1 (ip.3) uart0 0x0023 4 ri0 (scon0.0) ti0 (scon0.1) y n es0 (ie.4) ps0 (ip.4) timer 2 overflow 0x002b 5 tf2h (tmr2cn.7) tf2l (tmr2cn.6) y n et2 (ie.5) pt2 (ip.5) spi0 0x0033 6 spif (spi0cn.7) wcol (spi0cn.6) modf (spi0cn.5) rxovrn (spi0cn.4) y n espi0 (ie.6) pspi0 (ip.6) smb0 0x003b 7 si (smb0cn.0) y n esmb0 (eie1.0) psmb0 (eip1.0) reserved 0x0043 8 n/a n/a n/a n/a n/a adc0 window compare 0x004b 9 ad0wint (adc0cn.3) y n ewadc0 (eie1.2) pwadc0 (eip1.2) adc0 conversion complete 0x0053 10 ad0int (adc0cn.5) y n eadc0 (eie1.3) padc0 (eip1.3) programmable counter array 0x005b 11 cf (pca0cn.7) ccfn (pca0cn.n) y n epca0 (eie1.4) ppca0 (eip1.4) comparator0 0x0063 12 cp0fif (cpt0cn.4) cp0rif (cpt0cn.5) n n ecp0 (eie1.5) pcp0 (eip1.5) reserved 0x006b 13 n/a n/a n/a n/a n/a timer 3 overflow 0x0073 14 tf3h (tmr3cn.7) tf3l (tmr3cn.6) n n et3 (eie1.7) pt3 (eip1.7)
rev. 1.5 91 c8051f330/1/2/3/4/5 9.3.5. interrupt register descriptions the sfrs used to enable the interrupt sources and set t heir priority level are described below. refer to the data sheet section associated with a particular on-chi p peripheral for information regarding valid interrupt conditions for the peripheral and the behavior of its interrupt-pending flag(s). sfr definition 9.7. ie: interrupt enable bit7: ea: enable all interrupts. this bit globally enables/disabl es all interrupts. it overrides the individual interrupt mask set- tings. 0: disable all interrupt sources. 1: enable each interrupt accord ing to its individual mask setting. bit6: espi0: enable seri al peripheral interf ace (spi0) interrupt. this bit sets the masking of the spi0 interrupts. 0: disable all spi0 interrupts. 1: enable interrupt requests generated by spi0. bit5: et2: enable timer 2 interrupt. this bit sets the masking of the timer 2 interrupt. 0: disable timer 2 interrupt. 1: enable interrupt requests generated by the tf2l or tf2h flags. bit4: es0: enable uart0 interrupt. this bit sets the masking of the uart0 interrupt. 0: disable uart0 interrupt. 1: enable ua rt0 interrupt. bit3: et1: enable timer 1 interrupt. this bit sets the masking of the timer 1 interrupt. 0: disable all ti mer 1 interrupt. 1: enable interrupt requests generated by the tf1 flag. bit2: ex1: enable exte rnal interrupt 1. this bit sets the masking of external interrupt 1. 0: disable external interrupt 1. 1: enable interrupt requests generated by the /int1 input. bit1: et0: enable timer 0 interrupt. this bit sets the masking of the timer 0 interrupt. 0: disable all ti mer 0 interrupt. 1: enable interrupt requests generated by the tf0 flag. bit0: ex0: enable exte rnal interrupt 0. this bit sets the masking of external interrupt 0. 0: disable external interrupt 0. 1: enable interrupt requests generated by the /int0 input. r/w r/w r/w r/w r/w r/w r/w r/w reset value ea espi0 et2 es0 et1 ex1 et0 ex0 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: (bit addressable) 0xa8
c8051f330/1/2/3/4/5 92 rev. 1.5 sfr definition 9.8. ip: interrupt priority bit7: unused. read = 1, write = don't care. bit6: pspi0: serial periph eral interface (spi0) in terrupt priority control. this bit sets the priority of the spi0 interrupt. 0: spi0 interrupt set to low priority level. 1: spi0 interrupt set to high priority level. bit5: pt2: timer 2 interr upt priority control. this bit sets the priority of the timer 2 interrupt. 0: timer 2 interrupt set to low priority level. 1: timer 2 interrupt set to high priority level. bit4: ps0: uart0 interrupt priority control. this bit sets the priority of the uart0 interrupt. 0: uart0 interrupt set to low priority level. 1: uart0 interrupt set to high priority level. bit3: pt1: timer 1 interr upt priority control. this bit sets the priority of the timer 1 interrupt. 0: timer 1 interrupt set to low priority level. 1: timer 1 interrupt set to high priority level. bit2: px1: external interr upt 1 priority control. this bit sets the priority of the ex ternal interrupt 1 interrupt. 0: external interrupt 1 set to low priority level. 1: external interrupt 1 set to high priority level. bit1: pt0: timer 0 interr upt priority control. this bit sets the priority of the timer 0 interrupt. 0: timer 0 interrupt set to low priority level. 1: timer 0 interrupt set to high priority level. bit0: px0: external interr upt 0 priority control. this bit sets the priority of the ex ternal interrupt 0 interrupt. 0: external interrupt 0 set to low priority level. 1: external interrupt 0 set to high priority level. r r/w r/w r/w r/w r/w r/w r/w reset value - pspi0 pt2 ps0 pt1 px1 pt0 px0 10000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: (bit addressable) 0xb8
rev. 1.5 93 c8051f330/1/2/3/4/5 sfr definition 9.9. eie1: extended interrupt enable 1 bit7: et3: enable timer 3 interrupt. this bit sets the masking of the timer 3 interrupt. 0: disable timer 3 interrupts. 1: enable interrupt requests generated by the tf3l or tf3h flags. bit6: reserved. read = 0. must write 0. bit5: ecp0: enable comparator0 (cp0) interrupt. this bit sets the masking of the cp0 interrupt. 0: disable cp0 interrupts. 1: enable interrupt requests generated by the cp0rif or cp0fif flags. bit4: epca0: enable programmable counter array (pca0) interrupt. this bit sets the masking of the pca0 interrupts. 0: disable all pc a0 interrupts. 1: enable interrupt requests generated by pca0. bit3: eadc0: enable adc0 co nversion complete interrupt. this bit sets the masking of the adc0 conversion complete interrupt. 0: disable adc0 conver sion complete interrupt. 1: enable interrupt requests generated by the ad0int flag. bit2: ewadc0: enable window comparison adc0 interrupt. this bit sets the masking of adc0 window comparison interrupt. 0: disable adc0 window comparison interrupt. 1: enable interrupt requests generated by adc0 window compare flag (ad0wint). bit1: reserved. read = 0. must write 0. bit0: esmb0: enable smbu s (smb0) interrupt. this bit sets the masking of the smb0 interrupt. 0: disable all smb0 interrupts. 1: enable interrupt requests generated by smb0. r/w r/w r/w r/w r/w r/w r/w r/w reset value et3 reserved ecp0 epca0 eadc0 ew adc0 reserved esmb0 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xe6
c8051f330/1/2/3/4/5 94 rev. 1.5 sfr definition 9.10. eip1: extended interrupt priority 1 bit7: pt3: timer 3 interr upt priority control. this bit sets the priority of the timer 3 interrupt. 0: timer 3 interrupts se t to low priority level. 1: timer 3 interrupts set to high priority level. bit6: reserved. read = 0. must write 0. bit5: pcp0: comparator0 (cp0) interrupt prio rity control. this bit sets the priority of the cp0 interrupt. 0: cp0 interrupt set to low priority level. 1: cp0 interrupt set to high priority level. bit4: ppca0: programmable counter arra y (pca0) interrupt priority control. this bit sets the priority of the pca0 interrupt. 0: pca0 interrupt set to low priority level. 1: pca0 interrupt set to high priority level. bit3: padc0 adc0 conversion comp lete interrupt pr iority control. this bit sets the priority of the adc0 conversion complete interrupt. 0: adc0 conversion complete inte rrupt set to low priority level. 1: adc0 conversion complete inte rrupt set to high priority level. bit2: pwadc0: adc0 window comparator interrupt priority control. this bit sets the priority of the adc0 window interrupt. 0: adc0 window interrupt set to low priority level. 1: adc0 window interrupt se t to high priority level. bit1: reserved. read = 0. must write 0. bit0: psmb0: smbus (smb0) in terrupt priority control. this bit sets the priority of the smb0 interrupt. 0: smb0 interrupt set to low priority level. 1: smb0 interrupt set to high priority level. r/w r/w r/w r/w r/w r/w r/w r/w reset value pt3 reserved pcp0 ppca0 padc0 pwadc0 reserved psmb0 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xf6
rev. 1.5 95 c8051f330/1/2/3/4/5 sfr definition 9.11. it01cf: int0/int1 configuration bit7: in1pl: /int1 polarity 0: /int1 input is active low. 1: /int1 input is active high. bits6?4: in1sl2?0: /int1 port pin selection bits these bits select which port pin is assigned to /int1. note that this pin assignment is inde- pendent of the crossbar; /int 1 will monitor the assigned port pin without disturbing the peripheral that has been assi gned the port pin via the cr ossbar. the crossbar will not assign the port pin to a peripheral if it is c onfigured to skip the selected pin (accomplished by setting to ?1? the corresponding bit in register p0skip). bit3: in0pl: /int0 polarity 0: /int0 interrupt is active low. 1: /int0 interrupt is active high. bits2?0: int0sl2?0: /int0 port pin selection bits these bits select which port pin is assigned to /int0. note that this pin assignment is inde- pendent of the crossbar. /int 0 will monitor the assigned port pin without disturbing the peripheral that has been assi gned the port pin via the cr ossbar. the crossbar will not assign the port pin to a peripheral if it is c onfigured to skip the selected pin (accomplished by setting to ?1? the corresponding bit in register p0skip). r/w r/w r/w r/w r/w r/w r/w r/w reset value in1pl in1sl2 in1sl1 in1sl0 in0pl in0sl2 in0sl1 in0sl0 00000001 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xe4 *note: refer to sfr definition 18.1 for int0/1 edge- or level-sensitive interrupt selection. in1sl2 ? 0 /int1 port pin 000 p0.0 001 p0.1 010 p0.2 011 p0.3 100 p0.4 101 p0.5 110 p0.6 111 p0.7 in0sl2 ? 0 /int0 port pin 000 p0.0 001 p0.1 010 p0.2 011 p0.3 100 p0.4 101 p0.5 110 p0.6 111 p0.7
c8051f330/1/2/3/4/5 96 rev. 1.5 9.4. power management modes the cip-51 core has two software programmable power management modes: idle and stop. idle mode halts the cpu while leaving the peripherals and clocks active. in stop mode, the cpu is halted, all inter - rupts and timers (except the missing clock detector) ar e inactive, and the internal oscillator is stopped (analog peripherals remain in their selected states; the external osc illator is not effected ). since clocks are running in idle mode, power consumption is dependent upon the system clock frequency and the number of peripherals left in active mode before entering idle. stop mode consumes the least power. sfr defini - tion 9.12 describes the power control register (pcon) used to control the cip-51's power management modes. although the cip-51 has idle and stop modes built in (as with any standard 8051 architecture), power management of the entire mcu is better accomplished by enabling/disabling individual peripherals as needed. each analog peripheral can be disabled when not in use and placed in low power mode. digital peripherals, such as timers or serial buses, draw littl e power when they are not in use. turning off the oscil - lators lowers power consumption considerably; however a reset is required to restart the mcu. 9.4.1. idle mode setting the idle mode select bit (pcon.0) causes the cip-51 to halt the cpu and enter idle mode as soon as the instruction that sets the bit completes executio n. all internal registers and memory maintain their original data. all analog and digital peripherals can remain active during idle mode. idle mode is terminated when an enabled interrupt is asserted or a reset occurs. the assertion of an enabled interrupt will cause the idle mode selection bit (pcon.0) to be cleared and the cpu to resume operation. the pen ding interrupt will be serviced and the next in struction to be executed after the return from interrupt (reti) will be the instruction immedi ately following the one that se t the idle mode select bit. if idle mode is terminated by an internal or external reset, the cip-51 performs a normal reset sequence and begins program execution at address 0x0000. note: if the instructio n following the write of the idle bit is a sing le-byte instruction and an interrupt occurs during the execution phase of the instruction that sets the idle bit, the cpu may not wake from idle mode when a future interrupt occurs. therefore, instructi ons that set the idle bit should be followed by an instruction that has two or mo re opcode bytes, for example: // in ?c?: pcon |= 0x01; // set idle bit pcon = pcon; // ... followed by a 3-cycle dummy instruction ; in assembly: orl pcon, #01h ; set idle bit mov pcon, pcon ; ... followed by a 3-cycle dummy instruction if enabled, the watchdog timer (wdt) will eventually cause an internal watchdog reset and thereby termi - nate the idle mode. this feature protects the system from an unintended permanent shutdown in the event of an inadvertent write to the pcon register. if this behavior is not desired, th e wdt may be disabled by software prior to entering the idle mo de if the wdt was initially configured to allow this operation. this pro - vides the opportunity for additional power savings, allo wing the system to remain in the idle mode indefi - nitely, waiting for an external stimulus to wake up the system. refer to section ?10.6. pca watchdog timer reset? on page 102 for more information on the use and configuration of the wdt.
rev. 1.5 97 c8051f330/1/2/3/4/5 9.4.2. stop mode setting the stop mode select bit (pcon.1) causes the ci p-51 to enter stop mode as soon as the instruc - tion that sets the bit comp letes execution. in stop mo de the internal oscillator, cpu, and all digital peripher - als are stopped; the st ate of the external oscillator circuit is not affected. each analog peripheral (including the external oscillator circuit) may be shut down individually prior to entering stop mo de. stop mode can only be terminated by an internal or external reset. on reset, the cip-51 performs the normal reset sequence and begins program execution at address 0x0000. if enabled, the missing clock detect or will cause an internal reset and ther eby terminate th e stop mode. the missing clock detector should be disabled if the cpu is to be put to in stop mode for longer than the mcd timeout of 100 s. sfr definition 9.12. pcon: power control bits7?2: gf5?gf0: general purpose flags 5?0. these are general purpose flags for use under software control. bit1: stop: stop mode select. setting this bit will place the cip-51 in stop mode. this bit will always be read as 0. 1: cpu goes into stop mode (internal oscillator stopped). bit0: idle: idle mode select. setting this bit will place the cip-51 in idle mode. this bit will always be read as 0. 1: cpu goes into idle mode. (shuts off clock to cpu, but clock to time rs, interrupts, serial ports, and analog peripherals are still active.) r/w r/w r/w r/w r/w r/w r/w r/w reset value gf5 gf4 gf3 gf2 gf1 gf0 stop idle 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0x87
c8051f330/1/2/3/4/5 98 rev. 1.5
rev. 1.5 99 c8051f330/1/2/3/4/5 10. reset sources reset circuitry allows the controller to be easily placed in a predefined default condition. on entry to this reset state, th e following occur: ? cip-51 halts program execution ? special function registers (sfrs) are initialized to their defined reset values ? external port pins are forced to a known state ? interrupts and timers are disabled. all sfrs are reset to the predefined values noted in the sfr detailed descriptions. the contents of internal data memory are unaffected during a reset; any prev iously stored data is preserved. however, since the stack pointer sfr is reset, the stack is effectively lo st, even though the data on the stack is not altered. the port i/o latches are reset to 0xff (all logic ones) in open-drain mode. weak pullups are enabled dur - ing and after the reset. for v dd monitor and power-on resets, the rst pin is driven low until the device exits the reset state. on exit from the reset state, the program counter (pc) is reset, and the system clock defaults to the inter - nal oscillator. refer to section ?13. oscillators? on page 115 for information on sele cting and configuring the system clock source. the watchdog timer is enabled with the system clock divided by 12 as its clock source ( section ?19.3. watchdog timer mode? on page 203 details the use of the watchdog timer). program execution begins at location 0x0000. figure 10.1. reset sources pca wdt missing clock detector (one- shot) (software reset) system reset reset funnel px.x px.x en swrsf system clock cip-51 microcontroller core extended interrupt handler en wdt enable mcd enable errant flash operation /rst (wired-or) power on reset '0' + - comparator 0 c0rsef vdd + - supply monitor enable
c8051f330/1/2/3/4/5 100 rev. 1.5 10.1. power-on reset during power-up, the device is held in a reset state and the rst pin is driven low until v dd settles above v rst . a delay occurs before the device is released from reset; the delay decreases as the v dd ramp time increases (v dd ramp time is defined as how fast v dd ramps from 0 v to v rst ). figure 10.2 . plots the power-on and v dd monitor reset timing. the maximum v dd ramp time is 1 ms; slower ramp times may cause the device to be released from reset before v dd reaches the v rst level. for ramp times less than 1 ms, the power-on reset delay (t pordelay ) is typically less than 0.3 ms. on exit from a power-on reset, the porsf fl ag (rstsrc.1) is set by hardware to logic 1. when porsf is set, all of the other reset flags in the rstsrc regist er are indeterminate (porsf is cleared by all other resets). since all resets cause program execution to begin at the same location (0x0000) software can read the porsf flag to determine if a power-up was t he cause of reset. the content of internal data mem - ory should be assumed to be undefined after a power-on reset. the v dd monitor is disabled following a power-on reset. figure 10.2. power-on and v dd monitor reset timing 10.2. power-fail reset/v dd monitor when a power-down transition or power irregularity causes v dd to drop below v rst , the power supply monitor will drive the rst pin low and hold the cip-51 in a reset state (see figure 10.2 ). when v dd returns to a level above v rst , the cip-51 will be released from the reset st ate. note that even though internal data memory contents are not altered by the power-fa il reset, it is impossib le to determine if v dd dropped below the level required for data retention. if the porsf flag reads ?1?, the data may no longer be valid. the v dd monitor is disabled after power-on resets; however it s defined state (enabled/disabled) is not altered by any other reset source. for example, if the v dd monitor is enabled and a software reset is performed, the v dd monitor will still be enabled after the reset. power-on reset vdd monitor reset /rst t volts 1.0 2.0 logic high logic low t pordelay v d d 2.70 2.55 v rst vdd
rev. 1.5 101 c8051f330/1/2/3/4/5 important note: the v dd monitor must be enabled before it is selected as a reset source. selecting the v dd monitor as a reset source before it is enab led and stabilized may cause a system reset. the proce - dure for configuring the v dd monitor as a reset source is shown below: step 1. enable the v dd monitor (vdmen bit in vdm0cn = ?1?). step 2. wait for the v dd monitor to stabilize (see table 10.1 for the v dd monitor turn-on time). step 3. select the v dd monitor as a reset source (porsf bit in rstsrc = ?1?). see figure 10.2 for v dd monitor timing; note that the reset delay is not incurred after a v dd monitor reset. see ta b l e 10.1 for complete electrical characteristics of the v dd monitor. sfr definition 10.1. vdm0cn: v dd monitor control 10.3. external reset the external rst pin provides a means for external circuitry to force the device into a reset state. assert - ing an active-low signal on the rst pin generates a reset; an external pullup and/or decoupling of the rst pin may be necessary to avoid erroneous noise-induced resets. see table 10.1 for complete rst pin specifications. the pinrsf flag (rstsrc.0) is set on exit from an external reset. 10.4. missing clock detector reset the missing clock detector (mcd) is a one-shot circuit that is triggered by the syst em clock. if the system clock remains high or low for more than 100 s, the one-shot will time out an d generate a reset. after a mcd reset, the mcdrsf flag (rstsrc.2) will read ?1?, signifying the mcd as the reset source; otherwise, this bit reads ?0?. writing a ?1? to the mcdrsf bit enables the missing clo ck detector; writing a ?0? disables it. the state of the rst pin is unaffected by this reset. bit7: vdmen: v dd monitor enable. this bit turns the v dd monitor circuit on/off. the v dd monitor cannot generate system resets until it is also selected as a reset source in register rstsrc (sfr definition 10.2). the v dd monitor must be allowed to stabilize before it is selected as a reset source. selecting the v dd monitor as a reset source before it has stabilized may generate a system reset. see table 10.1 for the minimum v dd monitor turn-on time. 0: v dd monitor disabled. 1: v dd monitor enabled. bit6: v dd stat: v dd status. this bit indicates the current power supply status (v dd monitor output). 0: v dd is at or below the v dd monitor threshold. 1: v dd is above the v dd monitor threshold. bits5?0: reserved. read = 000000b. write = don?t care. r/wr rrrrr rreset value vdmen vddstat reserved reserved reserved reserved reserved reserved variable bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xff
c8051f330/1/2/3/4/5 102 rev. 1.5 10.5. comparator0 reset comparator0 can be configured as a reset source by writing a ?1? to the c0rsef flag (rstsrc.5). comparator0 should be enabled and allowed to settle prior to writing to c0rsef to prevent any turn-on chatter on the output from generating an unwanted rese t. the comparator0 reset is active-low: if the non- inverting input voltage (on cp0+) is le ss than the inverting input voltage (on cp0-), the device is put into the reset state. afte r a comparator0 reset, the c0rsef flag (rstsrc.5) will read ?1? signifying comparator0 as the reset source; otherwise, this bit reads ?0?. the state of the rst pin is unaffected by this reset. 10.6. pca watchdog timer reset the programmable watchdog timer (wdt) function of the programmable counter array (pca) can be used to prevent software from running out of cont rol during a system malfunction. the pca wdt function can be enabled or disabled by software as described in section ?19.3. watchdog timer mode? on page 203 ; the wdt is enabled and clocked by sysclk / 12 following any reset. if a system malfunction prevents user software from updating the wdt, a re set is generated and the wdtrsf bit (rstsrc.5) is set to ?1?. the state of the rst pin is unaffected by this reset. 10.7. flash error reset if a flash read/write/era se or program read targets an illegal address, a system reset is generated. this may occur due to any of the following: ? a flash write or erase is attempted above user code space. this occurs when pswe is set to ?1? and a movx write operation targets an address above address 0x1dff. ? a flash read is attempted above user code space. this occurs when a movc operation targets an address above address 0x1dff. ? a program read is attempted above user code spac e. this occurs when user code attempts to branch to an address above 0x1dff. ? a flash read, write or erase attempt is re stricted due to a flash security setting (see section ?11.3. security options? on page 107 ). the ferror bit (rstsrc.6) is set following a flash error reset. the state of the rst pin is unaffected by this reset. 10.8. software reset software may force a reset by writ ing a ?1? to the swrsf bit (rstsrc.4). the swrsf bit will read ?1? fol - lowing a software forced reset. the state of the rst pin is unaffected by this reset.
rev. 1.5 103 c8051f330/1/2/3/4/5 sfr definition 10.2. rstsrc: reset source note: do not use read-modify-write operations (orl, anl) on this register. bit7: unused. read = 0. write = don?t care. bit6: ferror: flash error indicator. 0: source of last reset was not a flash read/write/erase error. 1: source of last reset was a fl ashflash read/wri te/erase error. bit5: c0rsef: comparator0 reset enable and flag. 0: read: source of last reset was not comparator0. write: comparator0 is not a reset source. 1: read: source of last reset was comparator0. write: comparator0 is a reset source (active-low). bit4: swrsf: software reset force and flag. 0: read: source of last reset was no t a write to the swrsf bit. write: no effect. 1: read: source of last was a write to the swrsf bit. write: forces a system reset. bit3: wdtrsf: watchdog timer reset flag. 0: source of last reset was not a wdt timeout. 1: source of last reset was a wdt timeout. bit2: mcdrsf: missing clock detector flag. 0: read: source of last reset was not a missing clock detector timeout. write: missing clock detector disabled. 1: read: source of last reset was a mi ssing clock detector timeout. write: missing clock detector enabled; triggers a reset if a missing clock condition is detected. bit1: porsf: power-on reset force and flag. this bit is set anytime a power-on reset occurs. writing this bit enables/disables the v dd monitor as a reset source. note: writing ?1? to this bit before the v dd monitor is enabled and stabilized may cause a system reset. see register vdm0cn (sfr definition 10.1) 0: read: last reset was not a power-on or v dd monitor reset. write: v dd monitor is not a reset source. 1: read: last reset was a power-on or v dd monitor reset; all other reset flags indeterminate. write: v dd monitor is a reset source. bit0: pinrsf: hw pin reset flag. 0: source of last reset was not rst pin. 1: source of la st reset was rst pin. r r r/w r/w r r/w r/w r reset value - ferror c0rsef swrsf wdtrsf mcdrsf porsf pinrsf variable bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xef
c8051f330/1/2/3/4/5 104 rev. 1.5 table 10.1. reset electrical characteristics ?40 to +85 c unless otherwise specified. parameter conditions min typ max units rst output low voltage i ol = 8.5 ma, v dd = 2.7 v to 3.6 v ??0.6v rst input high voltage 0.7 x v dd ?? v rst input low voltage ? ? 0.3 x v dd rst input pullup current rst = 0.0 v ? 25 40 a v dd por threshold (v rst ) 2.40 2.55 2.70 v missing clock detector time- out time from last system clock rising edge to reset initiation 100 220 600 s reset time delay delay between release of any reset source and code execution at location 0x0000 5.0 ? ? s minimum rst low time to generate a system reset 15 ? ? s v dd monitor turn-on time 100 ? ? s v dd monitor supply current ?2050a
rev. 1.5 105 c8051f330/1/2/3/4/5 11. flash memory on-chip, re-programmable flash memory is included fo r program code and non-volatile data storage. the flash memory can be programmed in-system, a single by te at a time, through the c2 interface or by soft - ware using the movx instructio n. once cleared to logic 0, a flash bit must be erased to set it back to logic 1. flash bytes would typically be erased (set to 0xff) before being reprogrammed. the write and erase operations are automatically timed by hardware for proper execut ion; data polling to determine the end of the write/erase oper ation is not required. code execution is stalled during a flash write/erase oper - ation. refer to ta b l e 11.1 for complete flash memory electrical characteristics. 11.1. programming the flash memory the simplest means of programming the flash memory is through the c2 interface using programming tools provided by silicon labs or a third party vendor. this is the only means for programming a non-initial - ized device. for details on the c2 commands to program flash memory, see section ?20. c2 interface? on page 211 . to ensure the integrity of flash contents, it is strongly recommended that the on-chip v dd monitor be enabled in any system that includes code that writes and/or erases flash memory from soft - ware. see section 11.4 for more details. 11.1.1. flash lock and key functions flash writes and erases by user so ftware are protected with a lock and key function. th e flash lock and key register (flkey) must be writ ten with the correct key codes, in sequence, be fore flash operations may be performed. the key codes are: 0xa5, 0xf1. the timing does not matter, but the codes must be written in order. if the key codes are written out of or der, or the wrong codes are written, flash writes and erases will be disabled until the next system reset. flash writes and eras es will also be disabled if a flash write or erase is attempted before the key codes have been written properly. the flash lock resets after each write or erase; the key codes must be writte n again before a following flash operation can be per - formed. the flkey regist er is detailed in sfr definition 11.2 . 11.1.2. flash erase procedure the flash memory can be programmed by software using the movx write instru ction with the address and data byte to be programmed provided as normal ope rands. before writing to flash memory using movx, flash write operations must be enabled by: (1) setting the pswe program store write enable bit (psctl.0) to logic 1 (this directs the movx writes to target fl ash memory); and (2) writing the flash key codes in sequence to the flash lock register (flkey). the pswe bit remains set until cleared by soft - ware. a write to flash memory can clear bits to logic 0 but cannot set them; only an erase operation can set bits to logic 1 in flash. a byte location to be programmed should be erased before a new value is written. the flash memory is organized in 512-byte pages. the erase operation applies to an entire page (setting all bytes in the page to 0xff). to erase an en tire 512-byte page, perform the following steps: step 1. disable interrupts (recommended). step 2. set thepsee bit (register psctl). step 3. set the pswe bit (register psctl). step 4. write the first key code to flkey: 0xa5. step 5. write the second key code to flkey: 0xf1. step 6. using the movx instruction, write a data byte to any location within the 512-byte page to be erased. step 7. clear the pswe and psee bits.
c8051f330/1/2/3/4/5 106 rev. 1.5 11.1.3. flash write procedure flash bytes are programmed by software with the following sequence: step 1. disable interrupts (recommended). step 2. erase the 512-byte flash page containing the target location, as described in section 11.1.2 . step 3. set the pswe bit (register psctl). step 4. clear the psee bit (register psctl). step 5. write the first key code to flkey: 0xa5. step 6. write the second key code to flkey: 0xf1. step 7. using the movx instruction, write a single data byte to the desired location within the 512- byte sector. step 8. clear the pswe bit. steps 5?7 must be repeated for each byte to be written. after flash writes are complete, pswe should be cleared so that movx instructions do not target program memory. 11.2. non-volatile data storage the flash memory can be used for non-volatile data storage as well as program code. this allows data such as calibration coefficients to be calculated and stored at run time. data is written using the movx write instruction and read using the movc instructi on. note: movx read instructions always target xram. table 11.1. flash electrical characteristics v dd = 2.7 to 3.6 v; ? 40 to +85 oc unless otherwise specified. parameter conditions min typ max units flash size c8051f330/1 c8051f332/3 c8051f334/5 8192 * 4096 2048 ? ? ? ? ? ? bytes endurance 20 k 100 k ? erase/write erase cycle time 25 mhz system clock 10 15 20 ms write cycle time 25 mhz system clock 40 55 70 s *note: 512 bytes at addresses 0x1e00 to 0x1fff are reserved.
rev. 1.5 107 c8051f330/1/2/3/4/5 11.3. security options the cip-51 provides security options to protect the flash memory from inadvertent modification by soft - ware as well as to prevent the viewing of proprietary program code and constants. the program store write enable (bit pswe in register psctl) and the program store erase enable (bit psee in register psctl) bits protect the flash memory from accidental modification by software. pswe must be explicitly set to ?1? before software can modify the flash me mory; both pswe and psee must be set to ?1? before software can erase flash memory. additional security features prevent proprietary program code and data constants from being read or altered across the c2 interface. a security lock byte located at the last byte of fl ash user space offers protection of the flash program memory from access (reads, writes, or erases) by unpr otected code or the c2 inte rface. the flash security mechanism allows the user to lock n 512-byte flash pages, starting at page 0 (addresses 0x0000 to 0x01ff), where n is the 1?s complement number represented by the security lock byte. note that the page containing the flash security lock byte is unlocked when no other flash pages are locked (all bits of the lock byte are ?1?) and locked when any other flash pages are locked (any bit of the lock byte is ?0?). see example below. figure 11.2. flash program memory map security lock byte: 11111101b 1s complement: 00000010b flash pages locked: 3 (first tw o flash pages + lock byte page) addresses locked: 0x0000 to 0x03ff (first two flash pages) and 0x1c00 to 0x1dff or 0x0e00 to 0x0fff or 0x0600 to 0x07ff (lock byte page) locked flash pages access limit set according to the flash security lock byte c8051f334/5 0x0000 0x07ff lock byte reserved 0x07fe 0x800 flash memory organized in 512-byte pages 0x0600 unlocked flash pages locked when any other flash pages are locked locked flash pages c8051f332/3 0x0000 0x0fff lock byte reserved 0x0ffe 0x1000 0x0e00 unlocked flash pages locked flash pages c8051f330/1 0x0000 0x1dff lock byte reserved 0x1dfe 0x1e00 0x1c00 unlocked flash pages
c8051f330/1/2/3/4/5 108 rev. 1.5 the level of flash security depends on the flash ac cess method. the three flash access methods that can be restricted are reads, writes, an d erases from the c2 debug interface, user firmware executing on unlocked pages, and user firmware executing on locked pages. ta b l e 11.2 summarizes the flash security features of the 'f330/1/2/3/4/5 devices. table 11.2. flash security summary action c2 debug interface user firmware executing from: an unlocked page a locked page read, write or erase unlocked pages (except page with lock byte) permitted permitted permitted read, write or erase locked pages (except page with lock byte) not permitted flash error reset permitted read or write page containing lock byte (if no pages are locked) permitted permitted permitted read or write page containing lock byte (if any page is locked) not permitted flash error reset permitted read contents of lock byte (if no pages are locked) permitted permitted permitted read contents of lock byte (if any page is locked) not permitted flash error reset permitted erase page containing lock byte (if no pages are locked) permitted flash error reset flash error reset erase page containing lock byte - unlock all pages (if any page is locked) c2 device erase only flash error reset flash error reset lock additional pages (change '1's to '0's in the lock byte) not permitted flash error reset flash error reset unlock individual pages (change '0's to '1's in the lock byte) not permitted flash error reset flash error reset read, write or erase reserved area not permitted flash error reset flash error reset c2 device erase - erases all flash pages in cluding the page containing the lock byte. flash error reset - not permitted; causes flash erro r device reset (ferror bit in rstsrc is '1' after reset). - all prohibited operations that are performed via the c2 interface are ignored (do not cause device reset). - locking any flash page also locks th e page containing the lock byte. - once written to, the lock byte cannot be modifi ed except by performing a c2 device erase. - if user code writes to the lock byte, the lock does not take effect until the next device reset.
rev. 1.5 109 c8051f330/1/2/3/4/5 11.4. flash write and erase guidelines any system which contains routines which write or er ase flash memory from software involves some risk that the write or erase ro utines will execute unin tentionally if the cpu is op erating outside its specified operating range of v dd , system clock frequency, or temperature. this accidental execution of flash modi - fying code can result in alteration of flash memory contents causing a system failure that is only recover - able by re-flashing the code in the device. the following guidelines are recommended for any syst em which contains routin es which write or erase flash from code. 11.4.1. v dd maintenance and the v dd monitor 1. if the system power supply is subject to volta ge or current "spikes," add sufficient transient protection devices to the power supply to ensure that the supply voltages listed in the absolute maximum ratings table are not exceeded. 2. make certain that the minimum v dd rise time specification of 1 ms is met. if the system cannot meet this rise time specification, then add an external v dd brownout circuit to the rst pin of the device that holds the device in reset until v dd reaches 2.7 v and re-asserts rst if v dd drops below 2.7 v. 3. enable the on-chip v dd monitor and enable the v dd monitor as a reset source as early in code as possible. this should be the first set of in structions executed afte r the reset vector. for 'c'-based systems, this will involv e modifying the startup code ad ded by the 'c' compiler. see your compiler documentation for more details. make certain that there are no delays in soft - ware between enabling the v dd monitor and enabling the v dd monitor as a reset source. code examples showing this can be found in ?an201: writing to flash from firmware", avail - able from the silicon laboratories web site. 4. as an added precaution, explicitly enable the v dd monitor and enable the v dd monitor as a reset source inside the functions that write and erase flash memory. the v dd monitor enable instructions should be placed just after the in struction to set pswe to a '1', but before the flash write or erase operation instruction. 5. make certain that all writes to the rstsrc (r eset sources) register use direct assignment operators and explicitly do not use the bit-wis e operators (such as and or or). for exam - ple, "rstsrc = 0x02" is correct. "rstsrc |= 0x02" is incorrect. 6. make certain that all writes to the rstsrc regist er explicitly set the porsf bit to a '1'. areas to check are initialization code which enables ot her reset sources, such as the missing clock detector or comparator, for example, and instru ctions which force a software reset. a global search on "rstsrc" can quickly verify this. 11.4.2. pswe maintenance 7. reduce the number of places in code where t he pswe bit (b0 in psctl) is set to a '1'. there should be exactly one routine in code that sets pswe to a '1' to write flash bytes and one rou - tine in code that sets pswe and psee bo th to a '1' to erase flash pages. 8. minimize the number of variab le accesses while pswe is set to a '1'. handle pointer address updates and loop variable maintenance outside the "pswe = 1; ... pswe = 0;" area. code examples showing this can be found in an201, "writing to flash from firmware" , available from the silicon laboratories web site. 9. disable interrupts prior to setti ng pswe to a '1' and leave them disabled until after pswe has been reset to '0'. an y interrupts posted during the flash write or erase operation will be ser -
c8051f330/1/2/3/4/5 110 rev. 1.5 viced in priority order after the flash operation has been completed and interrupts have been re-enabled by software. 10. make certain that the flash write and erase pointer variables are not located in xram. see your compiler documentation for instructions regard ing how to explicitly lo cate variables in dif - ferent memory areas. 11. add address bounds checking to the routines th at write or erase flash memory to ensure that a routine called with an illegal address does not re sult in modification of the flash. 11.4.3. system clock 12. if operating from an external crystal, be advised that crystal performance is susceptible to electrical interference and is se nsitive to layout and to change s in temperature. if the system is operating in an electrically noisy environment, use t he internal oscillator or use an external cmos clock. 13. if operating from the ex ternal oscillator, switch to the internal oscillator during flash write or erase operations. the ex ternal oscillator can co ntinue to run, and the cpu can switch back to the external oscillator after th e flash operation has completed. additional flash recommendations and example code can be found in an201, "writing to flash from firm - ware" , available from the silic on laboratories web site. sfr definition 11.1. psctl: program store r/w control bits7?2: unused: read = 000000b, write = don?t care. bit1: psee: program store erase enable setting this bit (in combination with pswe) a llows an entire page of flash program memory to be erased. if this bit is logic 1 and flash writes are enabled (pswe is logic 1), a write to flash memory using the movx in struction will erase the entire page that contains the loca- tion addressed by the movx instruction. the va lue of the data byte written does not matter. 0: flash program memory erasure disabled. 1: flash program memory erasure enabled. bit0: pswe: program store write enable setting this bit allows writing a byte of data to the flash program memory using the movx write instruction. the flash location should be erased before writing data. 0: writes to flash program memory disabled. 1: writes to flash program memory enabled; the movx write instruction targets flash memory. rrrrrrr/wr/wreset value ? ? ? ? ? ? psee pswe 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0x8f
rev. 1.5 111 c8051f330/1/2/3/4/5 sfr definition 11.2. flkey: flash lock and key sfr definition 11.3. flscl: flash scale bits7?0: flkey: flash lock and key register write: this register provides a lock and key function for flash erasures and writes. flash writes and erases are enabled by writing 0xa5 fo llowed by 0xf1 to th e flkey register. flash writes and erases are aut omatically disabled after the next write or erase is complete. if any writes to flkey are performed inco rrectly, or if a fl ash write or erase ope ration is attempted while these operations are dis abled, the flash will be permanently locked fr om writes or era- sures until the next device reset. if an applicat ion never writes to flash, it can intentionally lock the flash by writing a non-0xa5 value to flkey from software. read: when read, bits 1?0 indicate the current flash lock state. 00: flash is write/erase locked. 01: the first key code has been written (0xa5). 10: flash is unlocked (w rites/erases allowed). 11: flash writes/erases disa bled until the next reset. r/w r/w r/w r/w r/w r/w r/w r/w reset value 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xb7 bit7: fose: flash one-shot enable this bit enables the flash read one-shot. w hen the flash one-shot disabled, the flash sense amps are enabled for a full clock cycle during flash reads. at system clock frequen- cies below 10 mhz, disabling the flash one-s hot will increase system power consumption. 0: flash one-shot disabled. 1: flash one-shot enabled. bits6?0: reserved. read = 0. must write 0. r/w r/w r/w r/w r/w r/w r/w r/w reset value fose reserved reserved reserved reserved reserved reserved reserved 10000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xb6
c8051f330/1/2/3/4/5 112 rev. 1.5
rev. 1.5 113 c8051f330/1/2/3/4/5 12. external ram the c8051f330/1/2/3/4/5 devices include 512 bytes of ram mapped into the external data memory space. all of these address locations may be access ed using the external move instruction (movx) and the data pointer (dptr), or using movx indirect addr essing mode. if the movx instruction is used with an 8-bit address operand (such as @r1), then the high byte of the 16-bit address is provided by the external memory interface control register (emi0cn as shown in sfr definition 12.1 ). note: the movx instruction is also used for writes to the flash memory. see section ?11. flash memory? on page 105 for details. the movx instruction accesses xram by default. for a 16-bit movx operation (@dptr), the upper 7 bits of the 16-bit external data memory address word are "don't cares". as a result, the 512-byte ram is mapped modulo style over the entire 64 k external data memory address range. for example, the xram byte at address 0x0000 is shadowed at addresses 0x0200, 0x0400, 0x0600, 0x0800, etc. this is a useful feature when perf orming a linear memory fill, as the address pointer doesn't have to be reset when reaching the ram block boundary. sfr definition 12.1. emi0cn: external memo ry interface control bits7?1: unused. read = 0000000b. write = don?t care. bit 0: pgsel: xram page select. the emi0cn register provides the high byte of the 16-bit external data memory address when using an 8-bit movx command, effectively selecting a 256-byte page of ram. since the upper (unused) bits of the register are always zero, the pgsel determines which page of xram is accessed. for example: if emi0cn = 0x01, addresse s 0x0100 through 0x01ff will be accessed. r/w r/w r/w r/w r/w r/w r/w r/w reset value ? ? ? ? ? ? ? pgsel 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xaa
c8051f330/1/2/3/4/5 114 rev. 1.5
rev. 1.5 115 c8051f330/1/2/3/4/5 13. oscillators c8051f330/1/2/3/4/5 devices include a programmable intern al high-frequency osc illator, a programmable internal low-freq uency oscillator, and an external oscillator dr ive circuit. the internal high-frequency oscilla - tor can be enabled/disabled and calibrated using the oscicn and oscicl re gisters, as shown in figure 13.1 . the internal low-frequency oscillator can be enabled/disabled and calibrated using the osclcn register, as shown in sfr definition 13.3 . the system clock can be sourced by the external oscillator circuit or either internal os cillator. both internal os cillators offer a selectab le post-scaling feature. the internal oscillators? electric al specifications are given in ta b l e 13.1 on page 124 . figure 13.1. oscillator diagram 13.1. programmable internal hi gh-frequency (h-f) oscillator all c8051f330/1/2/3/4/5 devices incl ude a programmable intern al high-frequency osc illator that defaults as the system clock after a system re set. the internal oscillator period can be adjusted via the oscicl register as defined by sfr definition 13.1 . on c8051f330/1/2/3/4/5 devices, oscicl is factory calibrated to obtain a 24.5 mhz base frequency. electrical specifications for the prec ision internal osc illator are given in table 13.1 on page 124 . note that the system clock may be derived from the programmed internal oscillator divided by 1, 2, 4, or 8, as defined by the ifcn bits in register oscicn. the divide value defaults to 8 following a reset. osc programmable internal clock generator input circuit en sysclk n oscicl oscicn ioscen ifrdy ifcn1 ifcn0 xtal1 xtal2 option 2 vdd xtal2 option 1 10m ? option 3 xtal2 option 4 xtal2 oscxcn xtlvld xoscmd2 xoscmd1 xoscmd0 xfcn2 xfcn1 xfcn0 clksel sel1 sel0 osclcn osclen osclrdy osclf3 osclf2 osclf1 osclf0 oscld1 oscld0 low frequency oscillator en n oscld osclf osclf oscld
c8051f330/1/2/3/4/5 116 rev. 1.5 sfr definition 13.1. oscicl: internal h-f oscillator calibration sfr definition 13.2. oscicn: internal h-f oscillator control bit7: unused. read = 0. write = don?t care. bits 6?0: oscicl: internal os cillator calibration register. this register determines the internal oscillato r period. when set to 0000000b, the h-f oscil- lator operates at its fastest setting. when set to 1111111b, the h-f oscillator operates at its slowest setting. on c8051f330/1 /2/3/4/5 devices, the reset va lue is factory calibrated to generate an internal oscilla tor frequency of 24.5 mhz. r r/w r/w r/w r/w r/w r/w r/w reset value - variable bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xb3 bit7: ioscen: internal h- f oscillator enable bit. 0: internal h-f oscillator disabled. 1: internal h-f oscillator enabled. bit6: ifrdy: internal h-f osc illator frequency ready flag. 0: internal h-f oscillator is no t running at prog rammed fr equency. 1: internal h-f oscillator is running at prog rammed frequency. bits5?2: unused. read = 0000b, write = don't care. bits1?0: ifcn1?0: internal h-f os cillator frequency control bits. 00: sysclk derived from internal h-f oscillator divided by 8. 01: sysclk derived from internal h-f oscillator divided by 4. 10: sysclk derived from internal h-f oscillator divided by 2. 11: sysclk derived from inter nal h-f oscillator divided by 1. r/w r r r r r r/w r/w reset value ioscen ifrdy - - - - ifcn1 ifcn0 11000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xb2
rev. 1.5 117 c8051f330/1/2/3/4/5 13.2. programmable internal low -frequency (l-f) oscillator all c8051f330/1/2/ 3/4/5 devices include a progra mmable low-frequency internal oscillator, which is cali - brated to a nominal frequency of 80 khz. the low-frequency oscillator circ uit includes a divider that can be changed to divide the clock by 1, 2, 4, or 8, using the oscld bits in the osclcn register (see sfr defi - nition 13.3 ). additionally, the osclf bits (osclcn5:2) can be used to adjust the oscillator?s output fre - quency. 13.2.1. calibrating the internal l-f oscillator timers 2 and 3 include capture func tions that can be used to capture the oscillato r frequency, when run - ning from a known time base. when either timer 2 or timer 3 is configured for l- f oscillator capture mode, a falling edge (timer 2) or rising edge (timer 3) of the low-frequency osc illator?s output will cause a capture event on the corresponding timer. as a capture event occurs, the current timer value (tmrnh:tmrnl) is copied into the timer reload re gisters (tmrnrlh:tmrnrll). by recording the differ - ence between two successive time r capture values, the lo w-frequency oscillator? s period can be calcu - lated. the osclf bits can then be adjusted to produce the desire d oscillator frequency. sfr definition 13.3. osclcn: internal l-f oscillator control bit7: osclen: internal l-f oscillator enable. 0: internal l-f oscillator disabled. 1: internal l-f oscillator enabled. bit6: osclrdy: internal l-f oscillator ready. 0: internal l-f oscillato r frequency not stabilized. 1: internal l-f oscilla tor frequency stabilized. bits5?2: osclf[3:0]: internal l-f oscillator frequen cy control bits. fine-tune control bi ts for the internal l-f oscillator frequency. when set to 0000b, the l-f oscillator operates at its fastest setting. when se t to 1111b, the l-f o scillator operates at its slowest setting. bits1?0: oscld[1:0]: internal l-f oscillator divider select. 00: divide by 8 selected. 01: divide by 4 selected. 10: divide by 2 selected. 11: divide by 1 selected. r/w r r/w r/w r/w r/w r/w r/w reset value osclen osclrdy osclf3 osclf2 osclf1 osclf0 oscld1 oscld0 00vvvv00 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xe3
c8051f330/1/2/3/4/5 118 rev. 1.5 13.3. external oscill ator drive circuit the external oscillator circuit may drive an external cr ystal, ceramic resona tor, capacitor, or rc network. a cmos clock may also provide a clock input. for a cr ystal or ceramic resonator configuration, the crys - tal/resonator must be wired across the xtal 1 and xtal2 pins as shown in option 1 of figure 13.1 . a 10 m ? resistor also must be wired across the xtal2 an d xtal1 pins for the crystal/resonator configura - tion. in rc, capacitor, or cmos cl ock configuration, the clock source should be wired to the xtal2 pin as shown in option 2, 3, or 4 of figure 13.1 . the type of external oscillator must be selected in the oscxcn register, and the frequency control bits (xfcn) must be selected appropriately (see sfr definition 13.4 ). important note on external oscillator usage: port pins must be configured when using the external oscillator circuit. when the external oscillator drive ci rcuit is enabled in crystal/r esonator mode, port pins p0.2 and p0.3 are used as xtal1 and xtal2 respectively. when the ex ternal oscillator drive circuit is enabled in capacitor, rc, or cmos clock mode, port pin p0.3 is used as xtal2. the port i/o crossbar should be configured to ski p the port pins used by the oscillator circuit; see section ?14.1. priority cross - bar decoder? on page 127 for crossbar configuratio n. additionally, when using the external oscillator cir - cuit in crystal/resonator, capaci tor, or rc mode, the associated port pins should be configured as analog inputs . in cmos clock mode, the associated pin should be configured as a digital input . see section ?14.2. port i/o initialization? on page 129 for details on port input mode selection.
rev. 1.5 119 c8051f330/1/2/3/4/5 sfr definition 13.4. oscxcn: external oscillator control bit7: xtlvld: crystal oscillator valid flag. (read only when xoscmd = 11x.) 0: crystal oscillator is unused or not yet stable. 1: crystal oscillator is running and stable. bits6?4: xoscmd2?0: extern al oscillator mode bits. 00x: external osc illator circuit off. 010: external cmos clock mode. 011: external cmos clock mode with divide by 2 stage. 100: rc oscillator mode. 101: capacitor oscillator mode. 110: crystal oscillator mode. 111: crystal oscillator mode with divide by 2 stage. bit3: reserved. read = 0, write = don't care. bits2?0: xfcn2?0: external osc illator frequency control bits. 000?111: see table below: crystal mode (circuit from figure 13.1 , option 1; xoscmd = 11x) choose xfcn value to match crystal frequency. rc mode (circuit from figure 13.1, option 2; xoscmd = 10x) choose xfcn value to match frequency range: f = 1.23(10 3 ) / (r * c) , where f = frequency of clock in mhz c = capacitor value in pf r = pullup resistor value in k ? c mode (circuit from figure 13.1, option 3; xoscmd = 10x) choose k factor (kf) for the oscillation frequency desired: f = kf / (c * v dd ) , where f = frequency of clock in mhz c = capacitor value the xtal2 pin in pf v dd = power supply on mcu in volts r r/w r/w r/w r r/w r/w r/w reset value xtlvld xoscmd2 xoscmd1 xoscmd 0 - xfcn2 xfcn1 xfcn0 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xb1 xfcn crystal (xoscmd = 11x) rc (xoscmd = 10x) c (xoscmd = 10x) 000 f 32 khz f 25 khz k factor = 0.87 001 32 khz < f 84 khz 25 khz < f 50 khz k factor = 2.6 010 84 khz < f 225 khz 50 khz < f 100 khz k factor = 7.7 011 225 khz < f 590 khz 100 khz < f 200 khz k factor = 22 100 590 khz < f 1.5 mhz 200 khz < f 400 khz k factor = 65 101 1.5 mhz < f 4 mhz 400 khz < f 800 khz k factor = 180 110 4 mhz < f 10 mhz 800 khz < f 1.6 mhz k factor = 664 111 10 mhz < f 30 mhz 1.6 mhz < f 3.2 mhz k factor = 1590
c8051f330/1/2/3/4/5 120 rev. 1.5 13.3.1. external crystal example if a crystal or ceramic resonator is used as an external oscillator source for the mcu, the circuit should be configured as shown in figure 13.1 , option 1. the external oscillato r frequency contro l value (xfcn) should be chosen from the crystal column of the table in sfr definition 13.4 (oscxcn register). for example, an 11.0592 mhz crystal requires an xfcn setting of 111b and a 32.768 khz watch crystal requires an xfcn setting of 001b. after an external 32.768 khz oscillator is stabilized, the xfcn setting can be switched to 000 to save power. it is recommended to enable the missing clock detector before switching the system clock to any external oscillator source. when the crystal oscillator is first e nabled, the oscillator amplitude detecti on circuit requires a settling time to achieve proper bias. introducing a delay of 1 ms between enabling the o scillator and checking the xtlvld bit will prevent a premature switch to the extern al oscillator as the system clock. switching to the external oscillator before the crysta l oscillator has stabilized can result in unpredictable behavior. the rec - ommended procedure is: step 1. force xtal1 and xtal2 to a low state. th is involves enabling the crossbar and writing ?0? to port latches p0.2 and p0.3. step 2. configure xtal1 and xtal2 as analog inputs using register p0mdin. step 3. enable the external oscillator. step 4. wait at least 1 ms. step 5. poll for xtlvld => ?1?. step 6. enable the missing clock detector. step 7. switch the system cl ock to the external oscillator. important note on external crystals: crystal oscillator circuits are qui te sensitive to pcb layout. the crystal should be placed as close as possible to the xtal pins on the device. the traces should be as short as possible and shielded with ground plane fr om any other traces which could introduce noise or interference.
rev. 1.5 121 c8051f330/1/2/3/4/5 the capacitors shown in the external crystal configur ation provide the load capacitance required by the crystal for correct oscillation. these capacitors are "in series" as seen by the crystal and "in parallel" with the stray capacitance of the xtal1 and xtal2 pins. note: the desired load capacitance depends upon the crystal and the manufacturer. please refer to the crystal data sheet when completing these calculations. for example, a tuning-fork crystal of 32.768 khz with a recommended load capacitance of 12.5 pf should use the configuration shown in figure 13.1 , option 1. the total value of th e capacitors and the stray capac - itance of the xtal pins should equal 25 pf. with a stray capacitance of 3 pf per pin, the 22 pf capacitors yield an equivalent capacitance of 12.5 pf across the crystal, as shown in figure 13.2 . figure 13.2. external 32.768 khz quartz crystal oscillator connection diagram xtal1 xtal2 10m ? 22pf* 22pf* 32.768 khz * capacitor values depend on crystal specifications
c8051f330/1/2/3/4/5 122 rev. 1.5 13.3.2. external rc example if an rc network is used as an external oscillator so urce for the mcu, the circ uit should be configured as shown in figure 13.1 , option 2. the capacitor should be no greater than 100 pf; however for very small capacitors, the total capacitance may be dominated by parasitic capacitance in the pcb layout. to deter - mine the required external oscilla tor frequency control va lue (xfcn) in the oscxcn register, first select the rc network value to prod uce the desired frequency of oscilla tion. if the frequency desired is 100 khz, let r = 246 k ? and c = 50 pf: f = 1.23( 10 3 ) / rc = 1.23 ( 10 3 ) / [ 246 x 50 ] = 0.1 mhz = 100 khz referring to the table in sfr definition 13.4 , the required xfcn setting is 010b. 13.3.3. external capacitor example if a capacitor is used as an external oscillator for t he mcu, the circuit should be configured as shown in figure 13.1 , option 3. the capacitor should be no greater than 100 pf; however for very small capacitors, the total capacitance may be dominated by parasiti c capacitance in the pcb layout. to determine the required external oscillato r frequency control value (xfcn) in th e oscxcn register, select the capaci - tor to be used and find the fr equency of oscillati on from the equations below. assume v dd = 3.0 v and f = 150 khz: f = kf / (c x vdd) 0.150 mhz = kf / (c x 3.0) since the frequency of roughly 150 khz is desi red, select the k factor from the table in sfr definition 13.4 (oscxcn) as kf = 22: 0.150 mhz = 22 / (c x 3.0) c x 3.0 = 22 / 0.150 mhz c = 146.6 / 3.0 pf = 48.8 pf therefore, the xfcn value to use in this example is 011b and c = 50 pf.
rev. 1.5 123 c8051f330/1/2/3/4/5 13.4. system clock selection the internal oscillator requir es little start-up time and may be selected as the s ystem clock immediately fol - lowing the oscicn write that enables the internal oscillator. external crystals and ceramic resonators typ - ically require a start-up time before they are settle d and ready for use. the crystal valid flag (xtlvld in register oscxcn) is set to '1' by hardwar e when the external oscillator is settled. in crystal mode, to avoid reading a false xtlvld, software should delay at least 1 ms between enabling the external oscillator and checking xtlvld. rc and c modes typically require no startup time. the clksl[1:0] bits in register cl ksel select which osc illator source is used as the system clock. clksl[1:0] must be set to 01b for the system clock to run from th e external oscillator; however the exter - nal oscillator may still clock certain per ipherals (timers, pca) when the inte rnal oscillator is selected as the system clock. the system clock may be switched on-the-fly be tween the intern al oscillator, external oscilla - tor, and clock multiplier so long as the selected clock source is enabled and has settled. sfr definition 13.5. clksel: clock select bits7?2: unused. read = 000000b, write = don't care. bits1?0: clksl[1:0]: system clock source select bits. 00: sysclk derived from the internal high-fr equency oscillator a nd scaled per the ifcn bits in register oscicn. 01: sysclk derived from the ex ternal oscillator circuit. 10: sysclk derived from the internal low-frequency oscilla tor and scaled per the oscld bits in register osclcn. 11: reserved. r r r r r r r/w r/w reset value - - - - - - clksl1 clksl0 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xa9
c8051f330/1/2/3/4/5 124 rev. 1.5 table 13.1. internal oscillator el ectrical characteristics v dd = 2.7 to 3.6 v; t a = ?40 to +85 c unless otherwise specified parameter conditions min typ max units internal high-frequency oscillator (u sing factory-calibrated settings) oscillator frequency ifcn = 11b 24 24.5 25 mhz oscillator supply current (from v dd ) 25 c, v dd = 3.0 v, oscicn.7 = 1 ? 450 ? a power supply sensitivit y constant temperature ? 0.3 0.1* ?% / v temperature sensitivity constant supply ? 50 10* ? ppm / c internal low-frequency oscillator (using factory-calibrated settings) oscillator frequency oscld = 11b 72 80 88 khz oscillator supply current (from v dd ) 25 c, v dd = 3.0 v, osclcn.7 = 1 ?5.5? a power supply sensitivity constant temperature ? ?3 0.1* ? %/v temperature sensitivity constant supply ? 20 8* ? ppm/c *note: represents mean 1 standard deviation.
rev. 1.5 125 c8051f330/1/2/3/4/5 14. port input/output digital and analog resources are available through 17 i/o pins. port pins are organized as two byte-wide ports and one 1-bit port. each of the port pins can be defined as general-purpose i/o (gpio) or analog input; port pins p0.0 - p1.7 can be assigned to one of the internal digital resources as shown in figure 14.3 . the designer has complete control over which functions are assigned, limited only by the number of physical i/o pins. this re source assignment flexibility is achi eved through the use of a priority crossbar decoder. note that the state of a port i/o pin can always be read in the corresponding port latch, regardless of the crossbar settings. the crossbar assigns the selected internal digital reso urces to the i/o pins based on the priority decoder ( figure 14.3 and figure 14.4 ). the registers xbr0 and xbr1, defined in sfr definition 14.1 and sfr definition 14.2 , are used to select internal digital functions. all port i/os are 5 v tolerant (refer to figure 14.2 for the port cell circuit). the port i/o cells are configured as either push-pull or open-drain in the port output mode registers (pnmdout, where n = 0,1). complete electrical specifications for port i/o are given in table 14.1 on page 136 . figure 14.1. port i/o fun ctional block diagram xbr0, xbr1, pnskip registers digital crossbar priority decoder 2 p0 i/o cells p0.0 p0.7 8 pnmdout, pnmdin registers uart (internal digital signals) highest priority lowest priority sysclk 2 smbus t0, t1 2 4 pca 4 spi cp0 outputs 2 p1 i/o cells p1.0 p1.7 8 (port latches) p0 (p0.0-p0.7) (p1.0-p1.7) 8 8 p1
c8051f330/1/2/3/4/5 126 rev. 1.5 figure 14.2. port i/o cell block diagram gnd /port-outenable port-output push-pull vdd vdd /weak-pullup (weak) port pad analog input analog select port-input
rev. 1.5 127 c8051f330/1/2/3/4/5 14.1. priority crossbar decoder the priority cro ssbar decoder ( figure 14.3 ) assigns a priority to each i/o function, starting at the top with uart0. when a digital resource is selected, the leas t-significant unassigned port pin is assigned to that resource (excluding uart0, which is a lways at pins 4 and 5). if a port pin is assigned, the crossbar skips that pin when assigning the next se lected resource. additionally, the crossbar will skip port pins whose associated bits in the pnskip registers are set. the pn skip registers allow software to skip port pins that are to be used for analog input, dedicated functions, or gpio. important note on crossbar configuration: if a port pin is claimed by a peripheral without use of the crossbar, its corresponding pnskip bit should be set. this applies to p0.0 if vref is used, p0.3 and/or p0.2 if the external oscillat or circuit is enabled, p0.6 if the adc or idac is configured to use the external conversion start signal (cnvstr), and any selected adc or comparator inputs. the crossbar skips selected pins as if they were already a ssigned, and moves to the next unassigned pin. figure 14.3 shows the crossbar decoder priority with no port pins skipped (p0skip, p1skip = 0x00); figure 14.4 shows the crossbar decoder priority with the xtal1 (p0. 2) and xtal2 (p0.3) pins skipped (p0skip = 0x0c). figure 14.3. crossbar priority decoder with no pins skipped p2 v re f ida x1 x2 cnvstr 01234567012345670 *nss is only pinned out in 4-wire spi mode sysclk cex0 cex1 cex2 eci 0000000000000000 cp0a special function signals are not assigned by the crossbar. when these signals are enabled, the crossbar must be manually configured to skip their corresponding port pins. port pin potentially available to peripheral sf signals t1 p0skip[0:7] t0 p1skip[0:7] tx0 cp0 sda scl p0 p1 nss* sck miso mosi rx0 sf signal s pin i/o
c8051f330/1/2/3/4/5 128 rev. 1.5 figure 14.4. crossbar priority d ecoder with crystal pins skipped registers xbr0 and xbr1 are used to assign the digital i/o resources to the physical i/o port pins. note that when the smbus is selected, the crossbar assi gns both pins associated with the smbus (sda and scl); when the uart is selected, the crossbar assign s both pins associated with the uart (tx and rx). uart0 pin assignments are fixed for bootloading purp oses: uart tx0 is always assigned to p0.4; uart rx0 is always assigned to p0.5. standard port i/os appear contiguously after the prioritized functions have been assigned. important note: the spi can be operated in either 3-wire or 4-wire modes, pending the state of the nssmd1?nssmd0 bits in register spi0cn. according to the spi mode, the nss signal may or may not be routed to a port pin. p2 v re f ida x1 x2 cnvstr 01234567012345670 *nss is only pinned out in 4-wire spi mode sysclk cex0 cex1 cex2 eci 0011000000000000 p0 p1 nss* sck miso mosi rx0 sf signal s pin i/o tx0 cp0 sda scl cp0a special function signals are not assigned by the crossbar. when these signals are enabled, the crossbar must be manually configured to skip their corresponding port pins. port pin potentially available to peripheral sf signals t1 p0skip[0:7] t0 p1skip[0:7]
rev. 1.5 129 c8051f330/1/2/3/4/5 14.2. port i/o initialization port i/o initialization cons ists of the following steps: step 1. select the input mode (analog or digital) for all port pins, using the port input mode register (pnmdin). step 2. select the output mode (open-drain or push -pull) for all port pins, using the port output mode register (pnmdout). step 3. select any pins to be skipped by the i/o crossbar using the port skip registers (pnskip). step 4. assign port pins to desired peripherals. step 5. enable the cr ossbar (xbare = ?1?). all port pins must be configured as either analog or digital inputs. any pins to be used as comparator or adc inputs should be configured as an analog inputs. when a pin is configured as an analog input, its weak pullup, digital driver, and digital receiver are disabled. this process save s power and reduces noise on the analog input. pins configured as digital inputs may still be used by analog peripherals; however this practice is not recommended. additionally, all analog input pins should be configur ed to be skipped by the crossbar (accomplished by setting the associated bits in pnskip). port input mode is set in the pnmdin register, where a ?1? indicates a digital input, and a ?0? indicates an analog input. all pins default to digital inputs on reset. see sfr defini - tion 14.4 for the pnmdin register details. the output driver characteristics of the i/o pins ar e defined using the port output mode registers (pnmd - out). each port output driver can be configured as either open drain or push- pull. this selection is required even for the digital resources selected in the xbrn registers, and is not automatic. the only exception to this is the smbus (sda, scl) pins, which are configured as open-drain regardless of the pnmdout settings. when the weakpud bi t in xbr1 is ?0?, a weak pullup is enabled for a ll port i/o con - figured as open-drain. w eakpud does not affect the push-pull port i/o. furthermo re, the weak pullup is turned off on an output that is driving a ?0? to avoid unnecessary power dissipation. registers xbr0 and xbr1 must be loaded with the approp riate values to select the digital i/o functions required by the design. setting the xbare bit in xbr1 to ?1? enables the cross bar. until the crossbar is enabled, the external pins remain as standard port i/o (in input mode), regardless of the xbrn register settings. for given xbrn register settings, one can de termine the i/o pin-out us ing the priority decode table; as an alternative, the confi guration wizard utility of the silicon labs ide software will determine the port i/o pin-assignments based on the xbrn register settings. the crossbar must be enabled to us e port pins as standard port i/o in output mode. port output drivers are disabled while the crossbar is disabled.
c8051f330/1/2/3/4/5 130 rev. 1.5 sfr definition 14.1. xbr0: port i/o cro ssbar register 0 bits7?6: unused. read = 00b, write = don?t care. bit5: cp0ae: comparator0 asynchronous output enable 0: asynchronous cp0 unavailable at port pin. 1: asynchronous cp0 routed to port pin. bit4: cp0e: comparator0 output enable 0: cp0 unavailable at port pin. 1: cp0 routed to port pin. bit3: syscke: /sysclk output enable 0: /sysclk unavaila ble at port pin. 1: /sysclk output r outed to port pin. bit2: smb0e: smbus i/o enable 0: smbus i/o unavailable at port pins. 1: smbus i/o routed to port pins. bit1: spi0e: spi i/o enable 0: spi i/o unavailable at port pins. 1: spi i/o routed to port pins. note that t he spi can be assigned either 3 or 4 gpio pins. bit0: urt0e: uart i/o output enable 0: uart i/o unavailable at port pin. 1: uart tx0, rx0 routed to port pins p0.4 and p0.5. r r r/w r/w r/w r/w r/w r/w reset value - - cp0ae cp0e syscke smb0 e spi0e urt0e 00000000 bit7 bit6 bit5 bit4 bit3 bi t2 bit1 bit0 sfr address: 0xe1
rev. 1.5 131 c8051f330/1/2/3/4/5 sfr definition 14.2. xbr1: port i/o cro ssbar register 1 14.3. general purpose port i/o port pins that remain unassigned by the crossbar and are not used by analog peripherals can be used for general purpose i/o. ports2?0 are accessed through corresponding special function registers (sfrs) that are both byte addressable and bit addressable. when writing to a port, the valu e written to the sfr is latched to maintain the output data value at each pin. when reading, the logic levels of the port's input pins are returned regardless of the xbrn settings (i.e., even when the pin is assigned to another signal by the crossbar, the port register can always read its corres ponding port i/o pin). the exception to this is the execution of the read-modify-write instructions that ta rget a port latch register as the destination. the read-modify-write instructions when operating on a port sfr are the following: anl, orl, xrl, jbc, cpl, inc, dec, djnz and mov, clr or setb, when the de stination is an individual bit in a port sfr. for these instructions, the value of the register (not the pin) is read, modified, and written back to the sfr. bit7: weakpud: port i/o weak pullup disable. 0: weak pullups enabled (except for ports whose i/o are configured as analog input). 1: weak pullups disabled. bit6: xbare: cros sbar enable. 0: crossbar disabled. 1: crossbar enabled. bit5: t1e: t1 enable 0: t1 unavailable at port pin. 1: t1 routed to port pin. bit4: t0e: t0 enable 0: t0 unavailable at port pin. 1: t0 routed to port pin. bit3: ecie: pca0 exter nal counter input enable 0: eci unavailable at port pin. 1: eci routed to port pin. bit2: unused. read = 0b. write = don?t care. bits1?0: pca0me: pca module i/o enable bits. 00: all pca i/o unavailable at port pins. 01: cex0 routed to port pin. 10: cex0, cex1 routed to port pins. 11: cex0, cex1, cex2 routed to port pins. r/w r/w r/w r/w r/w r r/w r/w reset value weakpud xbare t1e t0e ecie - pca0me 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xe2
c8051f330/1/2/3/4/5 132 rev. 1.5 sfr definition 14.3. p0: port0 sfr definition 14.4. p0mdin: port0 input mode bits7?0: p0.[7:0] write - output appears on i/o pins per crossbar registers. 0: logic low output. 1: logic high output (high impedance if corresponding p0mdout.n bit = 0). read - always reads ?0? if selected as analog input in register p0mdin. directly reads port pin when configured as digital input. 0: p0.n pin is logic low. 1: p0.n pin is logic high. r/w r/w r/w r/w r/w r/w r/w r/w reset value p0.7 p0.6 p0.5 p0.4 p0.3 p0.2 p0.1 p0.0 11111111 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: (bit addressable) 0x80 bits7?0: analog input configuration bits for p0.7?p0.0 (respectively). port pins configured as analog inputs have their weak pullup, digital driver, and digital receiver disabled. 0: corresponding p0.n pin is co nfigured as an analog input. 1: corresponding p0.n pin is not configured as an analog input. r/w r/w r/w r/w r/w r/w r/w r/w reset value 11111111 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xf1
rev. 1.5 133 c8051f330/1/2/3/4/5 sfr definition 14.5. p0mdout: port0 output mode sfr definition 14.6. p0skip: port0 skip sfr definition 14.7. p1: port1 bits7?0: output configuration bits for p0.7?p0.0 (res pectively): ignored if corresponding bit in regis- ter p0mdin is logic 0. 0: corresponding p0.n output is open-drain. 1: corresponding p0.n output is push-pull. (note: when sda and scl appear on any of the port i/o, each are open-drain regardless of the value of p0mdout). r/w r/w r/w r/w r/w r/w r/w r/w reset value 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xa4 bits7?0: p0skip[7:0]: port0 cr ossbar skip enable bits. these bits select port pins to be skipped by the crossbar decoder. port pins used as ana- log inputs (for adc or comparator) or used as special functions (vref input, external oscil- lator circuit, cnvstr input) should be skipped by the crossbar. 0: corresponding p0.n pin is not skipped by the crossbar. 1: corresponding p0.n pin is skipped by the crossbar. r/w r/w r/w r/w r/w r/w r/w r/w reset value 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xd4 bits7?0: p1.[7:0] write - output appears on i/o pins per crossbar registers. 0: logic low output. 1: logic high output (high impedance if corresponding p1mdout.n bit = 0). read - always reads ?0? if selected as analog input in register p1mdin. directly reads port pin when configured as digital input. 0: p1.n pin is logic low. 1: p1.n pin is logic high. r/w r/w r/w r/w r/w r/w r/w r/w reset value p1.7 p1.6 p1.5 p1.4 p1.3 p1.2 p1.1 p1.0 11111111 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: (bit addressable) 0x90
c8051f330/1/2/3/4/5 134 rev. 1.5 sfr definition 14.8. p1mdin: port1 input mode sfr definition 14.9. p1mdout: port1 output mode sfr definition 14.10. p1skip: port1 skip bits7?0: analog input configuration bits for p1.7?p1.0 (respectively). port pins configured as analog inputs have their weak pullup, digital driver, and digital receiver disabled. 0: corresponding p1.n pin is co nfigured as an analog input. 1: corresponding p1.n pin is not configured as an analog input. r/w r/w r/w r/w r/w r/w r/w r/w reset value 11111111 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xf2 bits7?0: output configuration bits for p1.7?p1.0 (res pectively): ignored if corresponding bit in regis- ter p1mdin is logic 0. 0: corresponding p1.n output is open-drain. 1: corresponding p1.n output is push-pull. r/w r/w r/w r/w r/w r/w r/w r/w reset value 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xa5 bit7: unused: read = 0b; write = don?t care. bits6?0: p1skip[6:0]: port1 cr ossbar skip enable bits. these bits select port pins to be skipped by the crossbar decoder. port pins used as ana- log inputs (for adc or comparator) or used as special functions (vref input, external oscil- lator circuit, cnvstr input) should be skipped by the crossbar. 0: corresponding p1.n pin is not skipped by the crossbar. 1: corresponding p1.n pin is skipped by the crossbar. r/w r/w r/w r/w r/w r/w r/w r/w reset value - 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xd5
rev. 1.5 135 c8051f330/1/2/3/4/5 sfr definition 14.11. p2: port2 sfr definition 14.12. p2mdout: port2 output mode bits7?1: unused. read = 0000000b. write = don?t care. bit0: p2.0 write - output appears on i/o pins per crossbar registers. 0: logic low output. 1: logic high output (high impedance if corresponding p2mdout.n bit = 0). read - directly reads port pin. 0: p2.n pin is logic low. 1: p2.n pin is logic high. rrrrrrrr/wreset value - - - - - - - p2.0 00000001 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: (bit addressable) 0xa0 bits7?1: unused. read = 0000000b. write = don?t care. bit0: output configuration bit for p2.0. 0: p2.0 output is open-drain. 1: p2.0 output is push-pull. rrrrrrrr/wreset value - - - - - - - 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xa6
c8051f330/1/2/3/4/5 136 rev. 1.5 table 14.1. port i/o dc electri cal characteristics v dd = 2.7 to 3.6 v, ?40 to +85 c unless otherwise specified. parameters conditions min typ max units output high voltage i oh = ?3 ma, port i/o push-pull i oh = ?10 a, port i/o push-pull i oh = ?10 ma, port i/o push-pull v dd ? 0.7 v dd ? 0.1 ? ? ? v dd ? 0.8 ? ? ? v output low voltage i ol = 8.5 ma i ol = 10 a i ol = 25 ma ? ? ? ? ? 1.0 0.6 0.1 ? v input high voltage 2.0 ? ? v input low voltage ? ? 0.8 v input leakage current weak pullup off weak pullup on, v in = 0 v ? ? ? 25 1 50 a
rev. 1.5 137 c8051f330/1/2/3/4/5 15. smbus the smbus i/o interface is a two-wire, bi-directional serial bus. the smbus is compliant with the system management bus specification, version 1.1, and compatible with the i2c serial bus. reads and writes to the interface by the system contro ller are byte oriented with the smbu s interface autonom ously controlling the serial transfer of the data. data can be transferre d at up to 1/10th of the system clock as a master or slave (this can be faster than allowed by the smbus specification, depending on the system clock used). a method of extending the clock-low duration is ava ilable to accommodate devices with different speed capabilities on the same bus. the smbus interface may operate as a master and/or slave, and may function on a bus with multiple mas - ters. the smbus provides control of sda (serial data), scl (serial clock) generation and synchronization, arbitration logic, and start/stop control and gene ration. three sfrs are associated with the smbus: smb0cf configures the sm bus; smb0cn controls the status of the smbus; and smb0dat is the data register, used for both transmitting and receiving smbus data and slave addresses. figure 15.1. smbus block diagram data path control smbus control logic c r o s s b a r scl filter n sda control scl control arbitration scl synchronization irq generation scl generation (master mode) sda control interrupt request port i/o smb0cn s t a a c k r q a r b l o s t a c k s i t x m o d e m a s t e r s t o 01 00 10 11 t0 overflow t1 overflow tmr2h overflow tmr2l overflow smb0cf e n s m b i n h b u s y e x t h o l d s m b t o e s m b f t e s m b c s 1 s m b c s 0 0 1 2 3 4 5 6 7 smb0dat sda filter n
c8051f330/1/2/3/4/5 138 rev. 1.5 15.1. supporting documents it is assumed the reader is fam iliar with or has access to th e following supporting documents: 1. the i2c-bus and how to use it (including specifications), philips semiconductor. 2. the i2c-bus specification?vers ion 2.0, philips semiconductor. 3. system management bus specification? version 1.1, sbs implementers forum. 15.2. smbus configuration figure 15.2 shows a typical smbus configuration. the smbu s specification allows any recessive voltage between 3.0 v and 5.0 v; different devices on the bus may operate at different voltage levels. the bi-direc - tional scl (serial clock) and sda (serial data) lines mu st be connected to a positive power supply voltage through a pullup resistor or similar circuit. every devi ce connected to the bus must have an open-drain or open-collector output for both the scl and sda lines, so that both are pulled high (recessive state) when the bus is free. the maximum number of devices on the bus is limited only by the requirement that the rise and fall times on the bus not exceed 300 ns and 1000 ns, respectively. figure 15.2. typical smbus configuration 15.3. smbus operation two types of data transfers are possible: data transfers from a master transmitter to an addressed slave receiver (write), and data transfers from an addres sed slave transmitter to a master receiver (read). the master device initiates both types of data transfer s and provides the serial clock pulses on scl. the smbus interface may operate as a master or a slave, and multiple master devices on the same bus are supported. if two or more masters attempt to initiate a data transfer simultaneously, an arbitration scheme is employed with a single master always winning the arbitr ation. note that it is not necessary to specify one device as the master in a system ; any device who transmits a star t and a slave address becomes the master for the duration of that transfer. a typical smbus transaction consists of a start cond ition followed by an address byte (bits7?1: 7-bit slave address; bit0: r/w direction bit), one or more byte s of data, and a stop condition. each byte that is received (by a master or slave) must be acknow ledged (ack) with a low sda during a high scl (see figure 15.3 ). if the receiving device does not ack, the transmitting devi ce will read a nack (not acknowl - edge), which is a high sda during a high scl. vdd = 5v master device slave device 1 slave device 2 vdd = 3v vdd = 5v vdd = 3v sda scl
rev. 1.5 139 c8051f330/1/2/3/4/5 the direction bit (r/w) occupies the least-significant bit position of the address byte. the direction bit is set to logic 1 to indicate a "read" operation and cleared to logic 0 to indicate a "write" operation. all transactions are initiated by a master, with one or more addressed slave devices as the target. the master generates the start condition and then transmit s the slave address and direction bit. if the trans - action is a write operation from the master to the slave, the master tr ansmits the data a byte at a time waiting for an ack from the slave at the end of each byte. for read operations , the slave transmits the data waiting for an ack from the master at the end of each byte. at the end of the data transfer, the master generates a stop condition to terminate the transaction and free the bus. figure 15.3 illustrates a typical smbus transaction. figure 15.3. smbus transaction 15.3.1. arbitration a master may start a transfer only if the bus is free. th e bus is free after a stop condition or after the scl and sda lines remain high for a specified time (see section ?15.3.4. scl high (smbus free) timeout? on page 140 ). in the event that two or more devices attemp t to begin a transfer at the same time, an arbi - tration scheme is employed to force one master to gi ve up the bus. the master devices continue transmit - ting until one attempts a high wh ile the other transmits a low. since the bus is open-drain, the bus will be pulled low. the master attemp ting the high will detect a low sda and lose the arbitration. the win - ning master continues its transmission without inte rruption; the losing master becomes a slave and receives the rest of the transfer if addressed. this arbitration scheme is non-destructive: one device always wins, and no data is lost. sla6 sda sla5-0 r/w d7 d6-0 scl slave address + r/w data byte start ack nack stop
c8051f330/1/2/3/4/5 140 rev. 1.5 15.3.2. clock low extension smbus provides a clock synchronizati on mechanism, similar to i2c, wh ich allows devices with different speed capabilities to coexist on the bus. a clock-low extension is used du ring a transfer in order to allow slower slave devices to communica te with faster masters. the slave may temporarily hold the scl line low to extend the clock low period, effectively decreasing the serial clock frequency. 15.3.3. scl low timeout if the scl line is held low by a slave device on the bus , no further communication is possible. furthermore, the master cannot force the scl line high to correct th e error condition. to solve this problem, the smbus protocol specifies that devices participating in a tran sfer must detect any clock cy cle held low longer than 25 ms as a ?timeout? condition. devices that have det ected the timeout condition must reset the communi - cation no later than 10 ms after detecting the timeout condition. when the smbtoe bit in smb0cf is set, timer 3 is used to detect scl low timeouts. timer 3 is forced to reload when scl is high, and allowed to count when scl is low. with timer 3 enabled and configured to overflow after 25 ms (and smbtoe set), the timer 3 interrupt service routine can be used to reset (disable and re-enable) the smbus in the event of an scl low timeout. 15.3.4. scl high (smbus free) timeout the smbus specification stipulates that if the scl and sda lines remain high for more that 50 s, the bus is designated as free. when the sm bfte bit in smb0cf is set, the bu s will be considered free if scl and sda remain high for more than 10 smbus clock source periods. if the smbus is waiting to generate a master start, the start will be generated following this timeout. note that a clock source is required for free timeout detection, even in a slave-only implementation. 15.4. using the smbus the smbus can operate in both master and slave modes. the interface provides timing and shifting con - trol for serial transfers; higher level protocol is dete rmined by user software. the smbus interface provides the following application-independent features: ? byte-wise serial data transfers ? clock signal generation on scl (master mode only) and sda data synchronization ? timeout/bus error recognition, as define d by the smb0cf configuration register ? start/stop timing, detection, and generation ? bus arbitration ? interrupt generation ? status information smbus interrupts are generated for each data byte or slave address that is transf erred. when transmitting, this interrupt is generated after the ack cycle so th at software may read the received ack value; when receiving data, this interrupt is generated before t he ack cycle so that software may define the outgoing ack value. see section ?15.5. smbus transfer modes? on page 148 for more details on transmission sequences. interrupts are also generated to indicate the beginning of a transfer when a master (start generated), or the end of a transfer when a slave (stop detected) . software should read the smb0cn (smbus control register) to find the cause of the smbus inte rrupt. the smb0cn register is described in section ?15.4.2. smb0cn control register? on page 145 ; table 15.4 provides a quick smb0cn decoding refer - ence.
rev. 1.5 141 c8051f330/1/2/3/4/5 smbus configuration options include: ? timeout detection (scl low timeout and/or bus free timeout) ? sda setup and hold time extensions ? slave event enable/disable ? clock source selection these options are selected in the smb0cf register, as described in section ?15.4.1. smbus configura - tion register? on page 142 .
c8051f330/1/2/3/4/5 142 rev. 1.5 15.4.1. smbus configuration register the smbus configuration register (s mb0cf) is used to enable the smbus master and/or slave modes, select the smbus clock source, and select the smbus timing and timeout options . when the ensmb bit is set, the smbus is enabled for all master and slave events. slave events may be disabled by setting the inh bit. with slave events inhibited, the smbus in terface will still monitor the scl and sda pins; however, the interface will nack all received addresses and will not generate any slave inte rrupts. when the inh bit is set, all slave events will be inhibited following the ne xt start (interrupts will cont inue for the duration of the current transfer). the smbcs1?0 bits select the smbus clock source, which is used only when operating as a master or when the free timeout detection is enabled. when op erating as a master, overflows from the selected source determine the absolute minimum scl low and high times as defined in equation 15.1 . note that the selected clock source may be shared by other peripherals so long as the timer is left running at all times. for example, timer 1 overflows may generate the smbus and uart baud rates simultaneously. timer configuration is covered in section ?18. timers? on page 179 . equation 15.1. minimum scl high and low times the selected clock source should be configured to establish the minimum scl high and low times as per equation 15.1 . when the interface is operating as a master (and scl is not driven or extended by any other devices on the bus), the typica l smbus bit rate is approximated by equation 15.2 . equation 15.2. typical smbus bit rate table 15.1. smbus clock source selection smbcs1 smbcs0 smbus clock source 0 0 timer 0 overflow 0 1 timer 1 overflow 1 0 timer 2 high byte overflow 1 1 timer 2 low byte overflow t highmin t lowmin 1 f clocksourceoverflow ---------------- ------------------ ----------- - == bitrate f clocksourceoverflow 3 --------------- ----------------- ------------- - =
rev. 1.5 143 c8051f330/1/2/3/4/5 figure 15.4 shows the typical scl generation described by equation 15.2 . notice that t high is typically twice as large as t low . the actual scl output may vary due to other devices on the bus (scl may be extended low by slower slave devices, or driven low by contending master devices). the bit rate when operating as a master will never exce ed the limits defined by equation equation 15.1 . figure 15.4. typical smbus scl generation setting the exthold bit extends the minimum setup and hold times for the sda line. the minimum sda setup time defines the absolute mini mum time that sda is stable before scl transitions from low-to-high. the minimum sda hold time defines the absolute minimum time that the current sda value remains stable after scl transitions from high-to-low. exthold should be set so that the minimum setup and hold times meet the smbus specification requirements of 250 ns and 300 ns, respectively. ta b l e 15.2 shows the min - imum setup and hold times for the two exthold settings. setup and hold time extensions are typically necessary when sysclk is above 10 mhz. with the smbtoe bit set, timer 3 should be configured to overflow after 25 ms in order to detect scl low timeouts (see section ?15.3.3. scl low timeout? on page 140 ). the smbus interface will force timer 3 to reload while scl is high, and allow timer 3 to count when scl is low. the timer 3 interrupt service rou - tine should be used to reset smbus communication by disabling and re-enabling the smbus. smbus free timeout detection can be enabled by setting the smbfte bit. when this bit is set, the bus will be considered free if sda and scl remain high for more than 10 smbus clock source periods (see figure 15.4 ). when a free timeout is dete cted, the interface will respond as if a stop was detected (an interrupt will be generat ed, and sto will be set). table 15.2. minimum sda setup and hold times exthold minimum sda setup time minimum sda hold time 0 t low ? 4 system clocks or 1 system clock + s/w delay * 3 system clocks 1 11 system clocks 12 system clocks *note: setup time for ack bit transmissions and the msb of all data transfers. the s/w delay occurs between the time smb0dat or ack is written and when si is cleared. note that if si is cleared in the same wr ite that defines the ou tgoing ack value, s/w delay is zero. scl timer source overflows scl high timeout t low t high
c8051f330/1/2/3/4/5 144 rev. 1.5 sfr definition 15.1. smb0cf: smbus clock/configuration bit7: ensmb: smbus enable. this bit enables/disables the smbus interface. when enabled, the interface constantly mon- itors the sda and scl pins. 0: smbus interface disabled. 1: smbus interface enabled. bit6: inh: smbus slave inhibit. when this bit is set to logic 1, the smbus does not generate an interrupt when slave events occur. this effectively removes the smbus slave from the bus. master mode interrupts are not affected. 0: smbus slave mode enabled. 1: smbus slave mode inhibited. bit5: busy: smbus busy indicator. this bit is set to logic 1 by hardware when a tran sfer is in progress. it is cleared to logic 0 when a stop or free-timeout is sensed. bit4: exthold: smbus setup and hold time extension enable. this bit controls the sda setup and hold times according to . 0: sda extended setup and hold times disabled. 1: sda extended setup and hold times enabled. bit3: smbtoe: smbus scl ti meout detection enable. this bit enables scl low timeout detection. if set to logic 1, the smbus forces timer 3 to reload while scl is high and allows timer 3 to count when scl goes low. if timer 3 is con- figured to split mode, only the high byte of th e timer is held in reload while scl is high. timer 3 should be programmed to generate interrupts at 25 ms, and the timer 3 interrupt service routine should reset smbus communication. bit2: smbfte: smbus free timeout detection enable. when this bit is set to logic 1, the bus will be considered free if scl and sda remain high for more than 10 smbus cl ock source periods. bits1?0: smbcs1?smbcs0: smbu s clock source selection. these two bits select the smbus clock source , which is used to generate the smbus bit rate. the selected device should be configured according to equation 15.1. r/w r/w r r/w r/w r/w r/w r/w reset value ensmb inh busy exthold smbtoe sm bfte smbcs1 smbcs0 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xc1 smbcs1 smbcs0 smbus clock source 0 0 timer 0 overflow 0 1 timer 1 overflow 1 0 timer 2 high byte overflow 1 1 timer 2 low byte overflow
rev. 1.5 145 c8051f330/1/2/3/4/5 15.4.2. smb0cn control register smb0cn is used to control the interface and to provide status information (see sfr definition 15.2 ). the higher four bits of smb0cn (master, txmode, sta, and sto) form a status vector that can be used to jump to service routines. master and txmode indi cate the master/slave state and transmit/receive modes, respectively. sta and sto indicate that a start and/or stop ha s been detected or generated since the last smbus interrupt. sta and sto are also used to generate start and stop conditions when operating as a mas - ter. writing a ?1? to sta will cause the smbus interfac e to enter master mode and generate a start when the bus becomes free (sta is not cleared by hardware after the start is generated). writing a ?1? to sto while in master mode will cause the interface to generate a stop and end the current transfer after the next ack cycle. if sto and sta are both set (while in master mode), a stop followed by a start will be generated. as a receiver, writing the ack bit defines the outgoing ack value; as a transmitter, reading the ack bit indicates the value received on the last ack cycle. ackrq is set each time a byte is received, indicating that an outgoing ack value is needed. when ackrq is set, software should write the desired outgoing value to the ack bit before clearing si. a nack will be generated if so ftware does not write the ack bit before clearing si. sda will reflec t the defined ack value immediately following a write to the ack bit; however scl will remain low un til si is cleared. if a received slave address is not acknowledged, further slave events will be ignored unt il the next start is detected. the arblost bit indicates that the interface has lost an arbitration. this may occur anytime the interface is transmitting (master or slave). a lost arbitratio n while operating as a slave indicates a bus error condi - tion. arblost is cleared by hardware each time si is cleared. the si bit (smbus interrupt flag) is set at the beginnin g and end of each transfer, after each byte frame, or when an arbitration is lost; see ta b l e 15.3 for more details. important note about the si bit: the smbus interface is stalled while si is set; thus scl is held low, and the bus is stalled until software clears si. ta b l e 15.3 lists all sources for hardware changes to the smb0cn bits. refer to ta b l e 15.4 for smbus sta - tus decoding using the smb0cn register.
c8051f330/1/2/3/4/5 146 rev. 1.5 sfr definition 15.2. smb0cn: smbus control bit7: master: smbus master/slave indicator. this read-only bit indicates when the smbus is operating as a master. 0: smbus operating in slave mode. 1: smbus operating in master mode. bit6: txmode: smbus transmit mode indicator. this read-only bit indicates when the smbus is operating as a transmitter. 0: smbus in receiver mode. 1: smbus in transmitter mode. bit5: sta: smbus start flag. write: 0: no start generated. 1: when operating as a master, a start condition is transmitted if the bus is free (if the bus is not free, the start is transmitted after a st op is received or a timeout is detected). if sta is set by software as an active mast er, a repeated start will be generated after the next ack cycle. read: 0: no start or repeated start detected. 1: start or repeated start detected. bit4: sto: smbus stop flag. write: 0: no stop condition is transmitted. 1: setting sto to logic 1 causes a stop condi tion to be transmitted after the next ack cycle. when the stop condition is generated, hardware clears sto to logic 0. if both sta and sto are set, a stop condition is transmitted followed by a start condition. read: 0: no stop condition detected. 1: stop condition detected (if in slave mode) or pending (if in master mode). bit3: ackrq: smbus ac knowledge request this read-only bit is set to logic 1 when the smbus has received a byte and needs the ack bit to be written with the correct ack response value. bit2: arblost: smbus arbitration lost indicator. this read-only bit is set to logic 1 when the smbus loses arbitration while operating as a transmitter. a lost arbitration while a slave indicates a bus error condition. bit1: ack: smbus acknowledge flag. this bit defines the out-going ack level and re cords incoming ack leve ls. it should be writ- ten each time a byte is rece ived (when ackrq=1), or read after each byte is transmitted. 0: a "not acknowledge" has bee n received (if in transmitter mode) or will be transmitted (if in receiver mode). 1: an "acknowledge" has been re ceived (if in transmitter mode) or will be transmitted (if in receiver mode). bit0: si: smbus interrupt flag. this bit is set by hardware under the conditions listed in table 15.3. si must be cleared by software. while si is set, scl is held low and the smbus is stalled. r r r/w r/w r r r/w r/w reset value master txmode sta sto ackrq arblost ack si 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 bit addressable sfr address: 0xc0
rev. 1.5 147 c8051f330/1/2/3/4/5 table 15.3. sources for hardware changes to smb0cn bit set by hardware when: cleared by hardware when: master ? a start is generated. ? a stop is generated. ? arbitration is lost. txmode ? start is generated. ? smb0dat is written before the start of an smbus frame. ? a start is detected. ? arbitration is lost. ? smb0dat is not written before the start of an smbus frame. sta ? a start followed by an address byte is received. ? must be cleared by software. sto ? a stop is detected while addressed as a slave. ? arbitration is lost due to a detected stop. ? a pending stop is generated. ackrq ? a byte has been received and an ack response value is needed. ? after each ack cycle. arblost ? a repeated start is detected as a master when sta is low (unwanted repeated start). ? scl is sensed low while attempting to gener - ate a stop or repeated start condition. ? sda is sensed low while transmitting a ?1? (excluding ack bits). ? each time si is cleared. ack ? the incoming ack value is low (acknowledge). ? the incoming ack value is high (not acknowledge). si ? a start has been generated. ? lost arbitration. ? a byte has been transmitted and an ack/nack received. ? a byte has been received. ? a start or repeated start followed by a slave address + r/w has been received. ? a stop has been received. ? must be cleared by software.
c8051f330/1/2/3/4/5 148 rev. 1.5 15.4.3. data register the smbus data register smb0dat holds a byte of serial data to be transmitted or one that has just been received. software may safely read or write to the data register when the si flag is set. software should not attempt to access the smb0dat register when the smbus is enabled and the si flag is cleared to logic 0, as the interface may be in the process of shifting a byte of data into or out of the register. data in smb0dat is always shifted ou t msb first. after a byte has been received, the first bit of received data is located at the msb of smb0dat. while data is being shifted out, data on the bus is simultaneously being shifted in. smb0dat always contains the last data byte present on the bus. in the event of lost arbi - tration, the transition from master transmitter to slave receiver is made with the correct data or address in smb0dat. sfr definition 15.3. smb0dat: smbus data 15.5. smbus transfer modes the smbus interface may be configured to operate as master and/or slave. at any particular time, it will be operating in one of the following four modes: master transmitter, master receiver, slave transmitter, or slave receiver. the smbus interface enters master mo de any time a start is generated, and remains in master mode until it loses an arbitration or generates a stop. an smbus interrupt is generated at the end of all smbus byte frames; however, note that the inte rrupt is generated before the ack cycle when operat - ing as a receiver, and after the ack cycle when operating as a transmitter. 15.5.1. master transmitter mode serial data is transmitted on sda while the serial cl ock is output on scl. the smbus interface generates the start condition and transmits the first byte cont aining the address of the target slave and the data direction bit. in this case the da ta direction bit (r/w) will be logic 0 (write). the master then transmits one or more bytes of serial data. after each byte is transmitted, an acknowled ge bit is generated by the slave. the transfer is en ded when the sto bit is set and a stop is generated. note that the interface will switch to master receiver mode if smb0dat is not written follo wing a master transmitter interrupt. figure 15.5 shows a typical master transmitter sequence. two transmit data bytes are shown, though any number of bytes may be transmitted. notice that the ?data byte transferred? interrupts occur after the ack cycle in this mode. bits7?0: smb0dat: smbus data. the smb0dat register contains a byte of data to be transmitted on the smbus serial inter- face or a byte that has just been received on the smbus serial interface. the cpu can read from or write to this register whenever the si serial interrupt flag (smb0cn.0) is set to logic 1. the serial data in the register remains stable as long as the si flag is set. when the si flag is not set, the system may be in the process of shifting data in/out and the cpu should not atte mpt to access this register. r/w r/w r/w r/w r/w r/w r/w r/w reset value 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xc2
rev. 1.5 149 c8051f330/1/2/3/4/5 figure 15.5. typical mast er transmitter sequence a a a s w p data byte data byte sla s = start p = stop a = ack w = write sla = slave address received by smbus interface transmitted by smbus interface interrupt interrupt interrupt interrupt
c8051f330/1/2/3/4/5 150 rev. 1.5 15.5.2. master receiver mode serial data is received on sda while the serial clock is output on scl. the smbus interface generates the start condition and transmits the first byte containing the address of the target slave and the data direc - tion bit. in this case the da ta direction bit (r/w) will be logic 1 (read). serial data is then received from the slave on sda while the smbus outputs the serial clock. the slave transmits one or more bytes of serial data. after each byte is received, ackrq is set to ?1? and an interrupt is generated. software must write the ack bit (smb0cn.1) to define the outgoing ackno wledge value (note: writing a ?1? to the ack bit gen - erates an ack; writing a ?0? genera tes a nack). software should write a ?0? to the ack bit after the last byte is received, to transmit a na ck. the interface exits master receiver mode after the sto bit is set and a stop is generated. the in terface will switch to master transmitter mode if smb0dat is written while an active master receiver. figure 15.6 shows a typical master receiver sequence. two received data bytes are shown, though any number of bytes may be received. notice that the ?data byte transferred? interrupts occur before the ack cycle in this mode. figure 15.6. typical m aster receiver sequence data byte data byte a n a s r p sla s = start p = stop a = ack n = nack r = read sla = slave address received by smbus interface transmitted by smbus interface interrupt interrupt interrupt interrupt
rev. 1.5 151 c8051f330/1/2/3/4/5 15.5.3. slave receiver mode serial data is received on sda and the clock is re ceived on scl. when slave events are enabled (inh = 0), the interface enters slave receiver mode when a start followed by a slave address and direction bit (write in this case) is received. upon entering slave receiver mode, an interrupt is generated and the ackrq bit is set. software responds to the received slave address with an ack, or ignores the received slave address with a nack. if the rece ived slave address is ignored, slav e interrupts will be inhibited until the next start is detected. if the received slave addr ess is acknowledged, zero or more data bytes are received. software must write the ack bit after each received byte to ack or nack the received byte. the interface exits slave receiver mode after receiving a stop. note that the interface will switch to slave transmitter mode if smb0 dat is written while an active slave receiver. figure 15.7 shows a typical slave receiver sequence. two received data bytes are show n, though any number of bytes may be received. notice that the ?data byte transferred? interrupts occur before the ack cycle in this mode. figure 15.7. typical sl ave receiver sequence p w sla s data byte data byte a a a s = start p = stop a = ack w = write sla = slave address received by smbus interface transmitted by smbus interface interrupt interrupt interrupt interrupt
c8051f330/1/2/3/4/5 152 rev. 1.5 15.5.4. slave transmitter mode serial data is transmitted on sda and the clock is re ceived on scl. when slave events are enabled (inh = 0), the interface enters slave receiver mode (to re ceive the slave address) when a start followed by a slave address and direction bit (read in this case) is received. upon entering slave transmitter mode, an interrupt is generated and the ackr q bit is set. software responds to the received slave address with an ack, or ignores the received slave address with a na ck. if the received slave address is ignored, slave interrupts will be inhibited un til a start is detected. if the received slave address is acknowledged, data should be written to smb0dat to be transmitted. the interface enters slave transmitter mode, and trans - mits one or more bytes of data. after each byte is tr ansmitted, the master sends an acknowledge bit; if the acknowledge bit is an ack, smb0dat should be writt en with the next data byte. if the acknowledge bit is a nack, smb0dat should not be written to before si is cleared (note: an error condition may be gener - ated if smb0dat is written following a received nack while in slave transmitter mode). the interface exits slave transmitter mode after receiving a stop. no te that the interface will sw itch to slave receiver mode if smb0dat is not written fo llowing a slave tran smitter interrupt. figure 15.8 shows a typical slave transmitter sequence. two transmitted data bytes ar e shown, though any number of bytes may be trans - mitted. notice that the ?data byte transferred? interrupts occur after the ack cycle in this mode. figure 15.8. typical sl ave transmitter sequence 15.6. smbus status decoding the current smbus status can be easily decoded usin g the smb0cn register. in the table below, status vector refers to the four upper bits of smb0 cn: master, txmode, sta, and sto. the shown response options are only the typica l responses; application-specific procedures are allowed as long as they conform to the smbus specification. highlighted responses are allowed but do not conform to the smbus specification. p r sla s data byte data byte a n a s = start p = stop n = nack r = read sla = slave address received by smbus interface transmitted by smbus interface interrupt interrupt interrupt interrupt
rev. 1.5 153 c8051f330/1/2/3/4/5 table 15.4. smbus status decoding mode values read current smbus state typical response options values written status vector ackrq arblost ack sta sto ack master transmitter 1110 0 0 x a master start was generated. load slave address + r/w into smb0dat. 0 0 x 1100 000 a master data or address byte was transmitted; nack received. set sta to restart transfer. 1 0 x abort transfer. 0 1 x 001 a master data or address byte was transmitted; ack received. load next data byte into smb0dat. 0 0 x end transfer with stop. 0 1 x end transfer with stop and start another transfer. 1 1 x send repeated start. 1 0 x switch to master receiver mode (clear si without writ - ing new data to smb0dat). 0 0 x master receiver 1000 1 0 x a master data byte was received; ack requested. acknowledge received byte; read smb0dat. 0 0 1 send nack to indicate last byte, and send stop. 0 1 0 send nack to indicate last byte, and send stop fol - lowed by start. 1 1 0 send ack followed by repeated start. 1 0 1 send nack to indicate last byte, and send repeated start. 1 0 0 send ack and switch to master transmitter mode (write to smb0dat before clearing si). 0 0 1 send nack and switch to master transmitter mode (write to smb0dat before clearing si). 0 0 0
c8051f330/1/2/3/4/5 154 rev. 1.5 slave transmitter 0100 000 a slave byte was transmitted; nack received. no action required (expect - ing stop condition). 0 0 x 001 a slave byte was transmitted; ack received. load smb0dat with next data byte to transmit. 0 0 x 01x a slave byte was transmitted; error detected. no action required (expect - ing master to end transfer). 0 0 x 0101 0 x x a stop was detected while an addressed slave transmitter. no action required (transfer complete). 0 0 x slave receiver 0010 10x a slave address was received; ack requested. acknowledge received address. 0 0 1 do not acknowledge received address. 0 0 0 11x lost arbitration as master; slave address received; ack requested. acknowledge received address. 0 0 1 do not acknowledge received address. 0 0 0 reschedule failed transfer; do not acknowledge received address. 1 0 0 0010 0 1 x lost arbitration while attempting a repeated start. abort failed transfer. 0 0 x reschedule failed transfer. 1 0 x 0001 11x lost arbitration while attempting a stop. no action required (transfer complete/aborted). 0 0 0 00x a stop was detected while an addressed slave receiver. no action required (transfer complete). 0 0 x 01x lost arbitration due to a detected stop. abort transfer. 0 0 x reschedule failed transfer. 1 0 x 0000 10x a slave byte was received; ack requested. acknowledge received byte; read smb0dat. 0 0 1 do not acknowledge received byte. 0 0 0 11x lost arbitration while transmitting a data byte as master. abort failed transfer. 0 0 0 reschedule failed transfer. 1 0 0 table 15.4. smbus status decoding mode values read current smbus state typical response options values written status vector ackrq arblost ack sta sto ack
rev. 1.5 155 c8051f330/1/2/3/4/5 16. uart0 uart0 is an asynchronous, full duplex serial port offering modes 1 and 3 of the standard 8051 uart. enhanced baud rate support allows a wide range of clock sources to generate standard baud rates (details in section ?16.1. enhanced baud rate generation? on page 156 ). received data buffering allows uart0 to start reception of a second incoming data byte before software has finished reading the previous data byte. uart0 has two associated sfrs: serial control regist er 0 (scon0) and serial data buffer 0 (sbuf0). the single sbuf0 location provides access to both transmit and receive registers. writes to sbuf0 always access the transmit register. reads of sbuf0 always access the buffered receive register; it is not possible to read data from the transmit register. with uart0 interrupts enabled, an interrupt is generate d each time a transmit is completed (ti0 is set in scon0), or a data byte has been received (ri0 is set in scon0). the uart 0 interrupt flags are not cleared by hardware when the cpu vectors to the interr upt service routine. they must be cleared manually by software, allowing software to determine the cause of the uart0 interrupt (transmit complete or receive complete). figure 16.1. uart0 block diagram uart baud rate generator ri scon ri ti rb8 tb8 ren mce smode tx control tx clock send sbuf (tx shift) start data write to sbuf crossbar tx shift zero detector tx irq set q d clr stop bit tb8 sfr bus serial port interrupt ti port i/o rx control start rx clock load sbuf shift 0x1ff rb8 rx irq input shift register (9 bits) load sbuf read sbuf sfr bus crossbar rx sbuf (rx latch)
c8051f330/1/2/3/4/5 156 rev. 1.5 16.1. enhanced baud rate generation the uart0 baud rate is generated by timer 1 in 8-bit auto-reload mode. the tx clock is generated by tl1; the rx clock is generated by a copy of tl1 (shown as rx timer in figure 16.2 ), which is not user- accessible. both tx and rx timer overflows are divid ed by two to generate the tx and rx baud rates. the rx timer runs when timer 1 is enabled, and uses the same reload value (th1). however, an rx timer reload is forced when a start condition is de tected on the rx pin. th is allows a receive to begin any time a start is detected, independent of the tx timer state. figure 16.2. uart0 baud rate logic timer 1 should be configured for mode 2, 8-bit auto-reload (see section ?18.1.3. mode 2: 8-bit counter/timer with auto-reload? on page 181 ). the timer 1 reload value should be set so that over - flows will occur at two times the desired ua rt baud rate frequency. note that timer 1 may be clocked by one of six source s: sysclk, sysclk / 4, sysclk / 12, sysclk / 48, the external oscillator clock / 8, or an external input t1. for any given timer 1 clock source, the uart0 baud rate is determined by equation 16.1 -a and equation 16.1 -b. equation 16.1. uart0 baud rate where t1 clk is the frequency of the clock supplied to timer 1, and t1h is the high byte of timer 1 (reload value). timer 1 clock frequency is selected as described in section ?18. timers? on page 179 . a quick reference for typical baud rates and system clock frequencies is given in ta b l e 16.1 through table 16.6 . note that the internal os cillator may still genera te the system clock wh en the external oscillator is driving timer 1. rx timer start detected overflow overflow th1 tl1 tx clock 2 rx clock 2 timer 1 uart uartbaudrate 1 2 -- - t1_overflow_rate = t1_overflow_rate t1 clk 256 th1 ? ------------ ------------- - = a) b)
rev. 1.5 157 c8051f330/1/2/3/4/5 16.2. operational modes uart0 provides standard asynchronous, full duplex communication. the uart mode (8-bit or 9-bit) is selected by the s0mode bit (scon0.7). typical uart connection options are shown below. figure 16.3. uart interconnect diagram 16.2.1. 8-bit uart 8-bit uart mode uses a total of 10 bits per data byte: one start bit, eight data bits (lsb first), and one stop bit. data are transmitted lsb first from the tx0 pin a nd received at the rx0 pin. on receive, the eight data bits are stored in sbuf0 and the stop bit goes into rb80 (scon0.2). data transmission begins wh en software writes a data byte to th e sbuf0 register. the ti0 transmit inter - rupt flag (scon0.1) is set at the end of the transmi ssion (the beginning of the stop-bit time). data recep - tion can begin any time after the ren0 rece ive enable bit (scon0.4) is set to logic 1. after the stop bit is received, the data byte w ill be loaded into the sbuf0 re ceive register if the follo wing conditions are met: ri0 must be logic 0, and if mce0 is logic 1, the stop bit must be logic 1. in the event of a receive data over - run, the first received 8 bits are latched into the sbuf0 receive register and the following overrun data bits are lost. if these conditions are met, the eight bits of data is stor ed in sbuf0, the stop bit is stored in rb80 and the ri0 flag is set. if these conditio ns are not met, sbuf0 and rb80 will no t be loaded and the ri0 flag will not be set. an interrupt will occur if enabled when ei ther ti0 or ri0 is set. figure 16.4. 8-bit u art timing diagram or rs-232 c8051fxxx rs-232 level xltr tx rx c8051fxxx rx tx mcu rx tx d1 d0 d2 d3 d4 d5 d6 d7 start bit mark stop bit bit times bit sampling space
c8051f330/1/2/3/4/5 158 rev. 1.5 16.2.2. 9-bit uart 9-bit uart mode uses a total of eleven bits per data byte: a start bit, 8 data bits (lsb first), a programma - ble ninth data bit, and a stop bit. the state of the nint h transmit data bit is determ ined by the value in tb80 (scon0.3), which is assigned by user software. it can be assigned the value of the parity flag (bit p in reg - ister psw) for error detection, or used in multiprocessor communications. on receive, the ninth data bit goes into rb80 (scon0.2) and the stop bit is ignored. data transmission begins when an instruction writes a data byte to the sbuf0 register. the ti0 transmit interrupt flag (scon0.1) is set at the end of the tran smission (the beginning of the stop-bit time). data reception can begin any time after the ren0 receive en able bit (scon0.4) is set to ?1?. after the stop bit is received, the data byte will be lo aded into the sbuf0 receiv e register if the followin g conditions are met: (1) ri0 must be logic 0, and (2) if mce0 is logic 1, the 9th bit must be logic 1 (when mce0 is logic 0, the state of the ninth data bit is unimportant). if these cond itions are met, the eight bits of data are stored in sbuf0, the ninth bit is stored in rb80, and the ri0 flag is set to ?1?. if the above conditions are not met, sbuf0 and rb80 will not be loaded and the ri0 flag will not be set to ?1?. a ua rt0 interrupt will occur if enabled when either ti0 or ri0 is set to ?1?. figure 16.5. 9-bit u art timing diagram 16.3. multiprocessor communications 9-bit uart mode supports multiprocessor communication between a master processor and one or more slave processors by special use of t he ninth data bit. when a master processor wants to transmit to one or more slaves, it first sends an address byte to select th e target(s). an address byte differs from a data byte in that its ninth bit is logic 1; in a data byte, the ninth bit is always set to logic 0. setting the mce0 bit (scon0.5) of a slave processor co nfigures its uart such that when a stop bit is received, the uart will gener ate an interrupt only if the ninth bit is logic 1 (rb80 = 1) signifying an address byte has been received. in the ua rt interrupt handler, software will compare the received address with the slave's own assigned 8-bit addre ss. if the addresses match, the slav e will clear its mce0 bit to enable interrupts on the reception of the following data byte (s). slaves that weren't addressed leave their mce0 bits set and do not generate interrupts on the reception of the following data bytes, thereby ignoring the data. once the entire message is received, the addres sed slave resets its mce0 bit to ignore all transmis - sions until it receives the next address byte. multiple addresses can be assigned to a single sl ave and/or a single address can be assigned to multiple slaves, thereby enabling "broadcast" transmissions to more than one slave simultaneously. the master processor can be configured to receive all transmissi ons or a protocol can be implemented such that the master/slave role is tem porarily reversed to enable half-duplex transmission between the original master and slave(s). d1 d0 d2 d3 d4 d5 d6 d7 start bit mark stop bit bit times bit sampling space d8
rev. 1.5 159 c8051f330/1/2/3/4/5 figure 16.6. uart multi-processor mode interconnect diagram master device slave device tx rx rx tx slave device rx tx slave device rx tx v+
c8051f330/1/2/3/4/5 160 rev. 1.5 sfr definition 16.1. scon0: serial port 0 control bit7: s0mode: serial port 0 operation mode. this bit selects the uart0 operation mode. 0: 8-bit uart with variable baud rate. 1: 9-bit uart with variable baud rate. bit6: unused. read = 1b . write = don?t care. bit5: mce0: multiprocessor communication enable. the function of this bit is dependent on the serial port 0 operation mode. s0mode = 0: checks for valid stop bit. 0: logic level of stop bit is ignored. 1: ri0 will only be activated if stop bit is logic level 1. s0mode = 1: multiprocesso r communications enable. 0: logic level of ninth bit is ignored. 1: ri0 is set and an interrupt is generated only when the ninth bit is logic 1. bit4: ren0: receive enable. this bit enables/disables the uart receiver. 0: uart0 reception disabled. 1: uart0 reception enabled. bit3: tb80: ninth transmission bit. the logic level of this bit will be assigned to the ninth transmission bit in 9-bit uart mode. it is not used in 8-bit uart mode. set or cleared by software as required. bit2: rb80: ninth receive bit. rb80 is assigned the value of the stop bit in mode 0; it is assigned the value of the 9th data bit in mode 1. bit1: ti0: transmit interrupt flag. set by hardware when a byte of data has been transmitted by uart0 (after the 8th bit in 8- bit uart mode, or at the beginning of the stop bit in 9-bit uart mode). when the uart0 interrupt is enabled, setting this bit causes the cpu to vector to the uart0 interrupt service routine. this bit must be cleared manually by software. bit0: ri0: receive interrupt flag. set to ?1? by hardware when a byte of data has been received by uart0 (set at the stop bit sampling time). when the uart0 interrupt is enab led, setting this bit to ?1? causes the cpu to vector to the uart0 interrupt service routine. this bit must be cleared manually by soft- ware. r/w r r/w r/w r/w r/w r/w r/w reset value s0mode - mce0 ren0 tb80 rb80 ti0 ri0 01000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 bit addressable sfr address: 0x98
rev. 1.5 161 c8051f330/1/2/3/4/5 sfr definition 16.2. sbuf0: serial (uart0 ) port data buffer bits7 ? 0: sbuf0[7:0]: serial data buffer bits 7 ? 0 (msb ? lsb) this sfr accesses two registers; a transmit shif t register and a receive latch register. when data is written to sbuf0, it goes to the transmit shift register and is he ld for serial transmis- sion. writing a byte to sbuf0 initiates the transmission. a read of sbuf0 returns the con- tents of the receive latch. r/w r/w r/w r/w r/w r/w r/w r/w reset value 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0x99
c8051f330/1/2/3/4/5 162 rev. 1.5 table 16.1. timer settings for standard ba ud rates using the internal 24.5 mhz oscillator frequency: 24.5 mhz target baud rate (bps) baud rate % error oscilla- tor divide factor timer clock source sca1?sca0 (pre-scale select) 1 t1m 1 timer 1 reload value (hex) sysclk from internal osc. 230400 ?0.32% 106 sysclk xx 2 1 0xcb 115200 ?0.32% 212 sysclk xx 1 0x96 57600 0.15% 426 sysclk xx 1 0x2b 28800 ?0.32% 848 sysclk/4 01 0 0x96 14400 0.15% 1704 sysclk/12 00 0 0xb9 9600 ?0.32% 2544 sysclk/12 00 0 0x96 2400 ?0.32% 10176 sysclk/48 10 0 0x96 1200 0.15% 20448 sysclk/48 10 0 0x2b notes: 1. sca1 ? sca0 and t1m bit definitions can be found in section 18.1 . 2. x = don?t care. table 16.2. timer settings for standard baud rates using an external 25.0 mhz oscillator frequency: 25.0 mhz target baud rate (bps) baud rate % error oscilla- tor divide factor timer clock source sca1?sca0 (pre-scale select) 1 t1m 1 timer 1 reload value (hex) sysclk from external osc. 230400 ?0.47% 108 sysclk xx 2 1 0xca 115200 0.45% 218 sysclk xx 1 0x93 57600 ?0.01% 434 sysclk xx 1 0x27 28800 0.45% 872 sysclk / 4 01 0 0x93 14400 ?0.01% 1736 sysclk / 4 01 0 0x27 9600 0.15% 2608 extclk / 8 11 0 0x5d 2400 0.45% 10464 sysc lk / 48 10 0 0x93 1200 ?0.01% 20832 sysc lk / 48 10 0 0x27 sysclk from internal osc. 57600 ?0.47% 432 extclk / 8 11 0 0xe5 28800 ?0.47% 864 extclk / 8 11 0 0xca 14400 0.45% 1744 extclk / 8 11 0 0x93 9600 0.15% 2608 extclk / 8 11 0 0x5d notes: 1. sca1 ? sca0 and t1m bit definitions can be found in section 18.1 . 2. x = don?t care.
rev. 1.5 163 c8051f330/1/2/3/4/5 table 16.3. timer settings for standard baud rates using an external 22.1184 mhz oscillator frequency: 22.1184 mhz target baud rate (bps) baud rate % error oscilla- tor divide factor timer clock source sca1?sca0 (pre-scale select) 1 t1m 1 timer 1 reload value (hex) sysclk from external osc. 230400 0.00% 96 sysclk xx 2 10xd0 115200 0.00% 192 sysclk xx 1 0xa0 57600 0.00% 384 sysclk xx 1 0x40 28800 0.00% 768 sysclk / 12 00 0 0xe0 14400 0.00% 1536 sysclk / 12 00 0 0xc0 9600 0.00% 2304 sysclk / 12 00 0 0xa0 2400 0.00% 9216 sysclk / 48 10 0 0xa0 1200 0.00% 18432 sysc lk / 48 10 0 0x40 sysclk from internal osc. 230400 0.00% 96 extclk / 8 11 0 0xfa 115200 0.00% 192 extclk / 8 11 0 0xf4 57600 0.00% 384 extclk / 8 11 0 0xe8 28800 0.00% 768 extclk / 8 11 0 0xd0 14400 0.00% 1536 extclk / 8 11 0 0xa0 9600 0.00% 2304 extclk / 8 11 0 0x70 notes: 1. sca1 ? sca0 and t1m bit definitions can be found in section 18.1 . 2. x = don?t care. table 16.4. timer settings for standard baud rates using an external 18.432 mhz oscillator frequency: 18.432 mhz target baud rate (bps) baud rate % error oscilla- tor divide factor timer clock source sca1?sca0 (pre-scale select) 1 t1m 1 timer 1 reload value (hex) sysclk from external osc. 230400 0.00% 80 sysclk xx 2 10xd8 115200 0.00% 160 sysclk xx 1 0xb0 57600 0.00% 320 sysclk xx 1 0x60 28800 0.00% 640 sysclk / 4 01 0 0xb0 14400 0.00% 1280 sysclk / 4 01 0 0x60 9600 0.00% 1920 sysclk / 12 00 0 0xb0 2400 0.00% 7680 sysclk / 48 10 0 0xb0 1200 0.00% 15360 sysclk / 48 10 0 0x60 sysclk from internal osc. 230400 0.00% 80 extclk / 8 11 0 0xfb 115200 0.00% 160 extclk / 8 11 0 0xf6 57600 0.00% 320 extclk / 8 11 0 0xec 28800 0.00% 640 extclk / 8 11 0 0xd8 14400 0.00% 1280 extclk / 8 11 0 0xb0 9600 0.00% 1920 extclk / 8 11 0 0x88 notes: 1. sca1 ? sca0 and t1m bit definitions can be found in section 18.1 . 2. x = don?t care.
c8051f330/1/2/3/4/5 164 rev. 1.5 table 16.5. timer settings for standard baud rates using an external 11.0592 mhz oscillator frequency: 11.0592 mhz target baud rate (bps) baud rate % error oscilla- tor divide factor timer clock source sca1?sca0 (pre-scale select) 1 t1m 1 timer 1 reload value (hex) sysclk from external osc. 230400 0.00% 48 sysclk xx 2 1 0xe8 115200 0.00% 96 sysclk xx 1 0xd0 57600 0.00% 192 sysclk xx 1 0xa0 28800 0.00% 384 sysclk xx 1 0x40 14400 0.00% 768 sysclk / 12 00 0 0xe0 9600 0.00% 1152 sysclk / 12 00 0 0xd0 2400 0.00% 4608 sysclk / 12 00 0 0x40 1200 0.00% 9216 sysclk / 48 10 0 0xa0 sysclk from internal osc. 230400 0.00% 48 extclk / 8 11 0 0xfd 115200 0.00% 96 extclk / 8 11 0 0xfa 57600 0.00% 192 extclk / 8 11 0 0xf4 28800 0.00% 384 extclk / 8 11 0 0xe8 14400 0.00% 768 extclk / 8 11 0 0xd0 9600 0.00% 1152 extclk / 8 11 0 0xb8 notes: 1. sca1 ? sca0 and t1m bit definitions can be found in section 18.1 . 2. x = don?t care. table 16.6. timer settings for standard ba ud rates using an external 3.6864 mhz oscillator frequency: 3.6864 mhz target baud rate (bps) baud rate% error oscilla- tor divide factor timer clock source sca1?sca0 (pre-scale select) 1 t1m 1 timer 1 reload value (hex) sysclk from external osc. 230400 0.00% 16 sysclk xx 2 10xf8 115200 0.00% 32 sysclk xx 1 0xf0 57600 0.00% 64 sysclk xx 1 0xe0 28800 0.00% 128 sysclk xx 1 0xc0 14400 0.00% 256 sysclk xx 1 0x80 9600 0.00% 384 sysclk xx 1 0x40 2400 0.00% 1536 sysclk / 12 00 0 0xc0 1200 0.00% 3072 sysclk / 12 00 0 0x80 sysclk from internal osc. 230400 0.00% 16 extclk / 8 11 0 0xff 115200 0.00% 32 extclk / 8 11 0 0xfe 57600 0.00% 64 extclk / 8 11 0 0xfc 28800 0.00% 128 extclk / 8 11 0 0xf8 14400 0.00% 256 extclk / 8 11 0 0xf0 9600 0.00% 384 extclk / 8 11 0 0xe8 notes: 1. sca1 ? sca0 and t1m bit definitions can be found in section 18.1 . 2. x = don?t care.
rev. 1.5 165 c8051f330/1/2/3/4/5 17. enhanced serial peri pheral interface (spi0) the enhanced serial peripheral interface (spi0) prov ides access to a flexible, full-duplex synchronous serial bus. spi0 can operate as a master or slave device in both 3-wire or 4-wire modes, and supports mul - tiple masters and slaves on a single spi bus. the slave-select (nss) signal can be configured as an input to select spi0 in slave mode, or to disable master mode operation in a multi-master environment, avoiding contention on the spi bus when more than one master attempts simultaneous data transfers. nss can also be configured as a chip-select output in master mode, or disabled for 3-wire operation. additional gen - eral purpose port i/o pins can be used to se lect multiple slave dev ices in master mode. figure 17.1. spi block diagram sfr bus data path control sfr bus write spi0dat receive data buffer spi0dat 0 1 2 3 4 5 6 7 shift register spi control logic spi0ckr scr7 scr6 scr5 scr4 scr3 scr2 scr1 scr0 spi0cfg spi0cn pin interface control pin control logic c r o s s b a r port i/o read spi0dat spi irq tx data rx data sck mosi miso nss transmit data buffer clock divide logic sysclk ckpha ckpol slvsel nssmd1 nssmd0 spibsy msten nssin srmt rxbmt spif wcol modf rxovrn txbmt spien
c8051f330/1/2/3/4/5 166 rev. 1.5 17.1. signal descriptions the four signals used by spi0 (mosi, miso, sck, nss) are described below. 17.1.1. master out, slave in (mosi) the master-out, slave-in (mosi) signal is an output fr om a master device and an input to slave devices. it is used to serially transfer data from the master to th e slave. this signal is an output when spi0 is operat - ing as a master and an input when spi0 is operating as a slave. data is transferred most-significant bit first. when configured as a master, mosi is driven by the msb of the shift register in both 3- and 4-wire mode. 17.1.2. master in, slave out (miso) the master-in, slave-out (miso) signal is an output from a slave device and an input to the master device. it is used to serially transfer data from the slave to the master. this signal is an input when spi0 is operat - ing as a master and an output when spi0 is operating as a slave. data is transferred most-significant bit first. the miso pin is placed in a high-impedance stat e when the spi module is disabled and when the spi operates in 4-wire mode as a slave that is not select ed. when acting as a slave in 3-wire mode, miso is always driven by the msb of the shift register. 17.1.3. serial clock (sck) the serial clock (sck) signal is an output from the mast er device and an input to slave devices. it is used to synchronize the transfer of data between the mast er and slave on the mosi and miso lines. spi0 gen - erates this signal when operating as a master. the sck signal is ignored by a spi slave when the slave is not selected (nss = 1) in 4-wire slave mode. 17.1.4. slave select (nss) the function of the slave-select (nss) signal is dependent on the setting of the nssmd1 and nssmd0 bits in the spi0cn register. there are three possib le modes that can be selected with these bits: 1. nssmd[1:0] = 00: 3-wire master or 3-wire slave mode: spi0 operates in 3-wire mode, and nss is disabled. when operating as a slave dev ice, spi0 is always selected in 3-wire mode. since no select signal is present, spi0 must be the only slave on the bus in 3-wire mode. this is intended for point-to-point communica tion between a master and one slave. 2. nssmd[1:0] = 01: 4-wire slave or multi-ma ster mode: spi0 operates in 4-wire mode, and nss is enabled as an input. when operating as a slave, nss selects the spi0 device. when operating as a master, a 1-to-0 transition of th e nss signal disables t he master function of spi0 so that multiple master devices can be used on the same spi bus. 3. nssmd[1:0] = 1x: 4-wire master mode: spi0 oper ates in 4-wire mode, and nss is enabled as an output. the setting of nssm d0 determines what logic leve l the nss pin will output. this configuration should only be used wh en operating spi0 as a master device. see figure 17.2 , figure 17.3 , and figure 17.4 for typical connection diagra ms of the various operational modes. note that the setting of nssmd bits affects the pinout of the device. when in 3-wire master or 3-wire slave mode, the nss pin will not be mapped by the crossbar. in all other modes, the nss signal will be mapped to a pin on the device. see section ? 14. port input/output ? on page 125 for general purpose port i/o and crossbar information.
rev. 1.5 167 c8051f330/1/2/3/4/5 17.2. spi0 master mode operation a spi master device initiates all data transfers on a spi bus. spi0 is placed in master mode by setting the master enable flag (msten, spi0cn.6). writing a byte of data to the spi0 data register (spi0dat) when in master mode writes to the transmit buffer. if the spi shift register is empty, the byte in the transmit buffer is moved to the shift register, and a data transfer begins. the spi0 master immediately shifts out the data serially on the mosi line while provid ing the serial clock on sck. the spi f (spi0cn.7) flag is set to logic 1 at the end of the transfer. if interrupts are enabl ed, an interrupt request is generated when the spif flag is set. while the spi0 master transf ers data to a slave on the mosi line, the addressed spi slave device simultaneously transfers the contents of its shift register to the spi master on the miso line in a full-duplex operation. therefore, the spif flag serves as both a transmit-complete and receive-data-ready flag. the data byte received from the slave is transferred msb-fi rst into the master's shift register. when a byte is fully shifted into the register, it is moved to the receive buffer where it can be read by the processor by reading spi0dat. when configured as a master, spi0 can operate in one of three different modes: multi-master mode, 3-wire single-master mode, and 4-wire single-master mode. the default, multi-master mode is active when nssmd1 (spi0cn.3) = 0 and nssmd0 (spi0cn.2) = 1. in this mode, nss is an input to the device, and is used to disable the master spi0 when another mast er is accessing the bus. when nss is pulled low in this mode, msten (spi0cn.6) and spien (spi0cn.0) ar e set to 0 to disable the spi master device, and a mode fault is generate d (modf, spi0cn.5 = 1). mode fault will gen erate an inte rrupt if e nabled. spi0 must be manually re-enabled in soft ware under these circumstances. in multi-master systems, devices will typically default to being slave devices while they are not acting as the system master device. in multi-mas - ter mode, slave devices can be addressed individua lly (if needed) using general-purpose i/o pins. figure 17.2 shows a connection diagram between two ma ster devices in mu ltiple-master mode. 3-wire single-master mode is active when nssmd1 (s pi0cn.3) = 0 and nssmd0 ( spi0cn.2) = 0. in this mode, nss is not used, and is not mapped to an exte rnal port pin through the crossbar. any slave devices that must be addressed in this mode should be selected using general-purpose i/o pins. figure 17.3 shows a connection diagram between a master dev ice in 3-wire master mode and a slave device. 4-wire single-master mode is active wh en nssmd1 (spi0cn.3) = 1. in this mode, nss is configured as an output pin, and can be used as a sl ave-select signal for a single spi dev ice. in this mode, the output value of nss is controlled (in software) with the bit nssm d0 (spi0cn.2). additional slave devices can be addressed using general-purpose i/o pins. figure 17.4 shows a connection diagram for a master device in 4-wire master mode and two slave devices.
c8051f330/1/2/3/4/5 168 rev. 1.5 figure 17.2. multiple-master mode connect ion diagram figure 17.3. 3-wire singl e master and 3-wire singl e slave mode connection diagram figure 17.4. 4-wire singl e master mode and 4-wire slave mode connection diagram master device 2 master device 1 mosi miso sck miso mosi sck nss gpio nss gpio slave device master device mosi miso sck miso mosi sck slave device master device mosi miso sck miso mosi sck nss nss gpio slave device mosi miso sck nss
rev. 1.5 169 c8051f330/1/2/3/4/5 17.3. spi0 slave mode operation when spi0 is enabled and not confi gured as a master, it will operate as a spi slave. as a slave, bytes are shifted in through the mosi pin a nd out through the miso pin by a ma ster device controlling the sck sig - nal. a bit counter in the spi0 logic counts sck edges. when 8 bits have been shifted through the shift reg - ister, the spif flag is set to logic 1, and the byte is copied into the receive buffer. data is read from the receive buffer by reading spi0dat. a slave device cannot initiate transfers. data to be transferred to the master device is pre-loaded into the shift register by writing to spi0dat. writes to spi0dat are double- buffered, and are placed in the transmit buffer first. if the shift register is empty, the contents of the transmit buffer will immediately be transferred into the shift register. when the sh ift register already contains data, the spi will load the shift register wi th the transmit buffer?s contents af ter the last sck edg e of the next (or current) spi transfer. when configured as a slave, spi0 can be configured for 4-wire or 3-wire operation. the default, 4-wire slave mode, is active when nssmd1 (spi0cn.3) = 0 and nssmd0 (spi0cn.2) = 1. in 4-wire mode, the nss signal is routed to a port pin and configured as a digital input. spi0 is enabl ed when nss is logic 0, and disabled when nss is logic 1. the bit counter is reset on a falling edge of n ss. note that the nss sig - nal must be driven low at least 2 system clocks before the first active edge of sck for each byte transfer. figure 17.4 shows a connection diagram between two slav e devices in 4-wire slave mode and a master device. 3-wire slave mode is active when nssmd1 (spi0cn. 3) = 0 and nssmd0 (spi0cn.2) = 0. nss is not used in this mode, and is not mapped to an external port pin through the crossbar. since there is no way of uniquely addressing the device in 3-wire slave mode , spi0 must be the only slav e device present on the bus. it is important to note that in 3-wire slave mode there is no external means of resetting the bit counter that determines when a full byte has been received. th e bit counter can only be reset by disabling and re- enabling spi0 with the spien bit. figure 17.3 shows a connection diagram between a slave device in 3- wire slave mode and a master device. 17.4. spi0 interrupt sources when spi0 interrupts are e nabled, the following four flags will gener ate an interrupt when they are set to logic 1: all of the following bits must be cleared by software. 1. the spi interrupt flag, spif (spi0cn.7) is set to logic 1 at the end of each byte transfer. this flag can occur in all spi0 modes. 2. the write collision flag, wcol (spi0cn.6) is set to logic 1 if a write to spi0dat is attempted when the transmit buffer has not been emptied to the spi shift register. when this occurs, the write to spi0dat will be ignored, and the transmi t buffer will not be written.this flag can occur in all spi0 modes. 3. the mode fault flag modf (spi0cn.5) is set to logic 1 when spi0 is configured as a master, and for multi-master mode and the nss pin is pulled low. when a mode fault occurs, the msten and spien bits in spi0cn are set to logi c 0 to disable spi0 and allow another master device to access the bus. 4. the receive overrun flag rxovrn (spi0cn.4) is set to logic 1 when configured as a slave, and a transfer is completed and the receive buffer still holds an unread byte from a previous transfer. the new byte is not transferred to the receive buffer, allowing the previously received data byte to be read. the data byte which caused the overrun is lost.
c8051f330/1/2/3/4/5 170 rev. 1.5 17.5. serial clock timing four combinations of serial clock phase and polarity can be selected using the clock control bits in the spi0 configuration register (spi0c fg). the ckpha bit ( spi0cfg.5) selects one of two clock phases (edge used to latch the data). the ckpol bit (spi0cfg.4) selects between an active-high or active-low clock. both master and slave devices must be config ured to use the same clock phase and polarity. spi0 should be disabled (by clearing the spien bit, spi0 cn.0) when changing the clock phase or polarity. the clock and data line relationships for master mode are shown in figure 17.5 . for slave mode, the clock and data relationships are shown in figure 17.6 and figure 17.7 . note that ckpha must be set to ?0? on both the master and slave spi when communicating betw een two of the following devices: c8051f04x, c8051f06x, c8051f12x, c8051f31x, c8051f32x, and c8051f33x the spi0 clock rate register (spi0ckr) as shown in sfr definition 17.3 controls the master mode serial clock frequency. this register is ignored when operating in slave mode. when the spi is configured as a master, the maximum data transfer rate (bits/sec) is one-half the s ystem clock frequency or 12.5 mhz, whichever is slower. when the spi is configured as a sl ave, the maximum data transfer rate (bits/sec) for full-duplex operation is 1/10 the system clock frequency , provided that the master issues sck, nss (in 4- wire slave mode), and the serial input data synchrono usly with the slave?s system clock. if the master issues sck, nss, and the serial input data asynchronously, the maximum data transfer rate (bits/sec) must be less than 1/10 the system clock frequency. in the special case where the master only wants to transmit data to the slave and does not need to receive data from the slave (i.e. half-duplex operation), the spi slave can receive data at a maximum data transfer rate (bits/sec) of 1/4 the system clock frequency. this is provided that the master i ssues sck, nss, and the serial inpu t data synchronously with the slave?s system clock. figure 17.5. master mode data/clock timing sck (ckpol=0, ckpha=0) sck (ckpol=0, ckpha=1) sck (ckpol=1, ckpha=0) sck (ckpol=1, ckpha=1) msb bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 miso/mosi nss (must remain high in multi-master mode)
rev. 1.5 171 c8051f330/1/2/3/4/5 figure 17.6. slave mode data /clock timing (ckpha = 0) figure 17.7. slave mode data /clock timing (ckpha = 1) 17.6. spi special function registers spi0 is accessed and controlled through four special function registers in the system controller: spi0cn control register, spi0dat data re gister, spi0cfg configuration register, and spi0ckr clock rate register. the four special function registers related to the operation of the spi0 bus are described in the following figures. msb bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 miso nss (4-wire mode) msb bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 mosi sck (ckpol=0, ckpha=0) sck (ckpol=1, ckpha=0) sck (ckpol=0, ckpha=1) sck (ckpol=1, ckpha=1) msb bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 miso nss (4-wire mode) msb bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 mosi
c8051f330/1/2/3/4/5 172 rev. 1.5 sfr definition 17.1. spi0cfg: spi0 configuration bit 7: spibsy: spi busy (read only). this bit is set to logic 1 when a spi transf er is in progress (master or slave mode). bit 6: msten: master mode enable. 0: disable master mode. operate in slave mode. 1: enable master mode. operate as a master. bit 5: ckpha: spi0 clock phase. this bit controls the spi0 clock phase. 0: data centered on first edge of sck period. * 1: data centered on second edge of sck period. * bit 4: ckpol: spi0 clock polarity. this bit controls the spi0 clock polarity. 0: sck line low in idle state. 1: sck line high in idle state. bit 3: slvsel: slave selected flag (read only). this bit is set to logic 1 whenever the nss pin is low indicating spi0 is the selected slave. it is cleared to logic 0 when nss is high (slave not selected). this bit does not indicate the instantaneous value at the nss pin, but ra ther a de-glitched version of the pin input. bit 2: nssin: nss instantaneous pin input (read only). this bit mimics the instantaneous value that is present on the nss port pin at the time that the register is read. this input is not de-glitched. bit 1: srmt: shift register empty (valid in slave mode, read only). this bit will be set to logic 1 when all data has been transferred in/out of the shift register, and there is no new information available to read from the transmit buffer or write to the receive buffer. it returns to logic 0 when a data byte is transferred to the shift register from the transmit buffer or by a transition on sck. note: srmt = 1 when in master mode. bit 0: rxbmt: receive buffer empty (valid in slave mode, read only). this bit will be set to logic 1 when the receiv e buffer has be en read and contains no new information. if there is new inform ation available in the receive buffer that has not been read, this bit will return to logic 0. note: rxbmt = 1 when in master mode. *note: in slave mode, data on mosi is sampled in the center of each data bit. in master mode, data on miso is sampled one sysclk before the end of each data bit, to provide maxi mum settling time fo r the slave device. see table 17.1 for timing parameters. r r/w r/w r/w r r r r reset value spibsy msten ckpha ckpol slvsel nssin srmt rxbmt 00000111 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xa1
rev. 1.5 173 c8051f330/1/2/3/4/5 sfr definition 17.2. spi0cn: spi0 control bit 7: spif: spi0 interrupt flag. this bit is set to logic 1 by hardware at the end of a data trans fer. if interrupts are enabled, setting this bit causes the cpu to vector to the spi0 interrupt service routine. this bit is not automatically cleared by hardware. it must be cleared by software. bit 6: wcol: write collision flag. this bit is set to logic 1 by hardware (and gene rates a spi0 interrupt) to indicate a write to the spi0 data register was attempted while a da ta transfer was in progress. it must be cleared by software. bit 5: modf: mode fault flag. this bit is set to logic 1 by hardware (and ge nerates a spi0 interrupt) when a master mode collision is detected (nss is low, msten = 1, and nssmd[1:0] = 01). this bit is not auto- matically cleared by hardware. it must be cleared by software. bit 4: rxovrn: receive overru n flag (slave mode only). this bit is set to logic 1 by hardware (and generates a spi0 interrupt) when the receive buffer still holds unread da ta from a previous transfer and the la st bit of the curr ent transfer is shifted into the spi0 shift register. this bit is not automatically cleare d by hardware. it must be cleared by software. bits 3 ? 2: nssmd1 ? nssmd0: slave select mode. selects between the following nss operation modes: (see section ?17.2. spi0 master mode operation? on page 167 and section ?17.3. spi0 slave mode operation? on page 169 ). 00: 3-wire slave or 3-wire master mode. nss signal is not routed to a port pin. 01: 4-wire slave or multi-master mode (defau lt). nss is always an input to the device. 1x: 4-wire single-master mode. nss signal is mapped as an ou tput from the device and will assume the value of nssmd0. bit 1: txbmt: transmit buffer empty. this bit will be set to logic 0 when new data ha s been written to the transmit buffer. when data in the transmit buffer is tr ansferred to the spi sh ift register, this bit will be set to logic 1, indicating that it is safe to writ e a new byte to the transmit buffer. bit 0: spien: spi0 enable. this bit enables/disables the spi. 0: spi disabled. 1: spi enabled. r/w r/w r/w r/w r/w r/w r r/w reset value spif wcol modf rxovrn nssmd1 nssmd0 txbmt spien 00000110 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 bit addressable sfr address: 0xf8
c8051f330/1/2/3/4/5 174 rev. 1.5 sfr definition 17.3. spi0ckr: spi0 clock rate sfr definition 17.4. spi0dat: spi0 data bits 7 ? 0: scr7 ? scr0: spi0 clock rate. these bits determine the frequency of the sck output when the spi0 module is configured for master mode operation. the sck clock frequ ency is a divided version of the system clock, and is given in the following equation, where sysclk is the system clock frequency and spi0ckr is the 8-bit value held in the spi0ckr register. for 0 <= spi0ckr <= 255 example: if sysclk = 2 mhz and spi0ckr = 0x04, r/w r/w r/w r/w r/w r/w r/w r/w reset value scr7 scr6 scr5 scr4 scr3 scr2 scr1 scr0 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xa2 f sck 2000000 241 + () --------------- ----------- = f sck 200 khz = f sck sysclk 2 spi 0 ckr 1 + () --------------- ------------------ --------------- - = bits 7 ? 0: spi0dat: spi0 transmit and receive data. the spi0dat register is used to transmit an d receive spi0 data. writing data to spi0dat places the data into the transmit buffer and initiates a transfer when in master mode. a read of spi0dat returns the contents of the receive buffer. r/w r/w r/w r/w r/w r/w r/w r/w reset value 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xa3
rev. 1.5 175 c8051f330/1/2/3/4/5 figure 17.8. spi master timing (ckpha = 0) figure 17.9. spi master timing (ckpha = 1) sck* t mckh t mckl mosi t mis miso * sck is shown for ckpol = 0. sck is the opposite polarity for ckpol = 1. t mih sck* t mckh t mckl miso t mih mosi * sck is shown for ckpol = 0. sck is the opposite polarity for ckpol = 1. t mis
c8051f330/1/2/3/4/5 176 rev. 1.5 figure 17.10. spi slave timing (ckpha = 0) figure 17.11. spi slave timing (ckpha = 1) sck* t se nss t ckh t ckl mosi t sis t sih miso t sd t soh * sck is shown for ckpol = 0. sck is the opposite polarity for ckpol = 1. t sez t sdz sck* t se nss t ckh t ckl mosi t sis t sih miso t sd t soh * sck is shown for ckpol = 0. sck is the opposite polarity for ckpol = 1. t slh t sez t sdz
rev. 1.5 177 c8051f330/1/2/3/4/5 table 17.1. spi slave timing parameters parameter description min max units master mode timing * (see figure 17.8 and figure 17.9 ) t mckh sck high time 1 x t sysclk ? ns t mckl sck low time 1 x t sysclk ? ns t mis miso valid to sck shift edge 1 x t sysclk + 20 ? ns t mih sck shift edge to miso change 0 ? ns slave mode timing * (see figure 17.10 and figure 17.11 ) t se nss falling to first sck edge 2 x t sysclk ? ns t sd last sck edge to nss rising 2 x t sysclk ? ns t sez nss falling to miso valid ? 4 x t sysclk ns t sdz nss rising to miso high-z ? 4 x t sysclk ns t ckh sck high time 5 x t sysclk ? ns t ckl sck low time 5 x t sysclk ? ns t sis mosi valid to sck sample edge 2 x t sysclk ? ns t sih sck sample edge to mosi change 2 x t sysclk ? ns t soh sck shift edge to miso change ? 4 x t sysclk ns t slh last sck edge to miso change (ckpha = 1 only) 6 x t sysclk 8 x t sysclk ns *note: t sysclk is equal to one period of the device system clock (sysclk).
c8051f330/1/2/3/4/5 178 rev. 1.5
rev. 1.5 179 c8051f330/1/2/3/4/5 18. timers each mcu includes four counter/timers: two are 16-bit counter/timers compatible with those found in the standard 8051, and two are 16-bit auto-reload timer fo r use with the adc, smbus, or for general purpose use. these timers can be used to measure time inte rvals, count external even ts and generate periodic interrupt requests. timer 0 and timer 1 are nearly identical and have four primary modes of operation. timer 2 and timer 3 offer 16-bit and split 8-bit timer functionality with auto-reload timers 0 and 1 may be clocked by one of five sources, determined by the timer mode select bits (t1m ? t0m) and the clock scale bits (sca1 ? sca0). the clock scale bits define a pre-scaled clock from which timer 0 and/or timer 1 may be clocked (see sfr definition 18.3 for pre-scaled cl ock selection). timer 0/1 may then be configured to use this pre-sc aled clock signal or th e system clock. timer 2 and timer 3 may be clocked by the system clock, the system clock divided by 12, or the external oscillator clock source divided by 8. timer 0 and timer 1 may also be operated as counters. when functioning as a counter, a counter/timer register is incremented on each high-to-low transition at the selected input pin (t0 or t1). events with a fre - quency of up to one-fourth the system clock frequen cy can be counted. the input signal need not be peri - odic, but it should be held at a gi ven level for at least two full system cl ock cycles to ensure the level is properly sampled. 18.1. timer 0 and timer 1 each timer is implemented as a 16-bit register acce ssed as two separate bytes: a low byte (tl0 or tl1) and a high byte (th0 or th1). the counter/timer co ntrol register (tcon) is used to enable timer 0 and timer 1 as well as indicate status. timer 0 interrupts can be enabled by setting the et0 bit in the ie regis - ter ( section ? 9.3.5. interrupt register descriptions ? on page 91 ); timer 1 interrupts can be enabled by setting the et1 bit in the ie register ( section 9.3.5 ). both counter/timers operate in one of four primary modes selected by setting the mode select bits t1m1 ? t0m0 in the counter/timer mode register (tmod). each timer can be configured independently. each operating mode is described below. 18.1.1. mode 0: 13-bit counter/timer timer 0 and timer 1 operate as 13-bit counter/timers in mode 0. the following describes the configuration and operation of timer 0. however, both timers operate identically, and timer 1 is configured in the same manner as described for timer 0. the th0 register holds the eight msbs of the 13-bit c ounter/timer. tl0 holds the five lsbs in bit positions tl0.4 ? tl0.0. the three upper bits of tl0 (tl0.7 ? tl0.5) are indeterminate and should be masked out or ignored when reading. as the 13-bit timer register increments and overflows from 0x1fff (all ones) to 0x0000, the timer overflow flag tf0 (tcon.5) is set and an interr upt will occur if timer 0 interrupts are enabled. timer 0 and timer 1 modes: ti mer 2 modes: timer 3 modes: 13-bit counter/timer 16-bit timer with auto-reload 16-bit timer with auto-reload 16-bit counter/timer 8-bit counter/timer with auto- reload two 8-bit timers with auto-reload t wo 8-bit timers with auto-reload two 8-bit counter/timers (timer 0 only)
c8051f330/1/2/3/4/5 180 rev. 1.5 the c/t0 bit (tmod.2) selects the counter/time r's clock source. when c/t0 is set to logic 1, high-to-low transitions at the selected timer 0 input pin (t0) increment the timer register (refer to section ?14.1. priority crossbar decoder? on page 127 for information on selecting and configuring external i/o pins). clearing c/t selects the clock defined by the t0m bit (ckcon.3). when t0m is set, timer 0 is clocked by the system clock. when t0m is cleared, timer 0 is clocked by the source selected by the clock scale bits in ckcon (see sfr definition 18.3 ). setting the tr0 bit (tcon.4) enables the ti mer when either gate0 (tmod.3) is logic 0 or the input signal /int0 is active as defined by bit in0pl in register it01cf (see sfr definition 9.11 ). setting gate0 to ?1? allows the timer to be controlled by the external input signal /int0 (see section ? 9.3.5. interrupt register descriptions ? on page 91 ), facilitating pulse width measurements setting tr0 does not force the timer to reset. the timer registers should be loaded with the desired initial value before the timer is enabled. tl1 and th1 form the 13-bit register for timer 1 in the same manner as described above for tl0 and th0. timer 1 is configured and controlled using the releva nt tcon and tmod bits just as with timer 0. the input signal /int1 is used with timer 1; the /int1 polarity is defined by bit in1pl in register it01cf (see sfr definition 9.11 ). figure 18.1. t0 mode 0 block diagram 18.1.2. mode 1: 16-bit counter/timer mode 1 operation is the same as mode 0, except that the counte r/timer registers use all 16 bits. the counter/timers are enabled and configured in mode 1 in the same manner as for mode 0. tr0 gate0 /int0 counter/timer 0 x x disabled 1 0 x enabled 1 1 0 disabled 111 enabled note: x = don't care tclk tl0 (5 bits) th0 (8 bits) tcon tf0 tr0 tr1 tf1 ie 1 it1 ie 0 it0 interrupt tr0 0 1 0 1 sysclk pre-scaled clock ckcon t 3 m h t 3 m l s c a 0 s c a 1 t 0 m t 2 m h t 2 m l t 1 m tmod t 1 m 1 t 1 m 0 c / t 1 g a t e 1 g a t e 0 c / t 0 t 0 m 1 t 0 m 0 gate0 /int0 t0 crossbar it01cf i n 1 s l 1 i n 1 s l 0 i n 1 s l 2 i n 1 p l i n 0 p l i n 0 s l 2 i n 0 s l 1 i n 0 s l 0 in 0pl xor
rev. 1.5 181 c8051f330/1/2/3/4/5 18.1.3. mode 2: 8-bit counter/timer with auto-reload mode 2 configures timer 0 and timer 1 to operate as 8-bit counter/timers with automatic reload of the start value. tl0 holds the count and th0 holds the reload va lue. when the counter in tl0 overflows from all ones to 0x00, the timer over flow flag tf0 (tcon.5) is set and the co unter in tl0 is reloaded from th0. if timer 0 interrupts are enabled, an interr upt will occur when the tf0 flag is set. the reload value in th0 is not changed. tl0 must be initialized to the desired va lue before enabling the timer for the first count to be correct. when in mode 2, timer 1 operates identically to timer 0. both counter/timers are enabled and configured in mode 2 in the same manner as mode 0. setting the tr0 bit (tcon.4) enables the timer w hen either gate0 (tmod.3) is logic 0 or when the input signal /int0 is active as defined by bit in0pl in register it01cf (see section ? 9.3.2. external interrupts ? on page 89 for details on the external input signals /int0 and /int1). figure 18.2. t0 mode 2 block diagram tclk tmod t 1 m 1 t 1 m 0 c / t 1 g a t e 1 g a t e 0 c / t 0 t 0 m 1 t 0 m 0 tcon tf0 tr0 tr1 tf1 ie1 it1 ie0 it0 interrupt tl0 (8 bits) reload th0 (8 bits) 0 1 0 1 sysclk pre-scaled clock it01cf i n 1 s l 1 i n 1 s l 0 i n 1 s l 2 i n 1 p l i n 0 p l i n 0 s l 2 i n 0 s l 1 i n 0 s l 0 tr0 gate0 in0pl xor /int0 t0 crossbar ckcon t 3 m h t 3 m l s c a 0 s c a 1 t 0 m t 2 m h t 2 m l t 1 m
c8051f330/1/2/3/4/5 182 rev. 1.5 18.1.4. mode 3: two 8-bit counter/timers (timer 0 only) in mode 3, timer 0 is configured as two separate 8-bit co unter/timers held in tl0 and th0. the counter/timer in tl0 is controlled using the timer 0 control/status bits in tcon and tmod: tr0, c/t0, gate0 and tf0. tl0 can use either the system clock or an external input signal as its timebase. the th0 register is restricted to a timer function sourced by the system clock or prescaled clock. th0 is enabled using the timer 1 run control bit tr1. th0 sets the timer 1 overflow flag tf1 on overflow and thus controls the timer 1 interrupt. timer 1 is inactive in mode 3. when timer 0 is operating in mode 3, timer 1 can be operated in modes 0, 1 or 2, but cannot be clocked by external signals nor set the tf1 flag and generate an interrupt. however, the timer 1 overflow can be used to generate baud rates for the smbus and/or uart, and/or initiate adc conversions. while timer 0 is operating in mode 3, timer 1 run control is handled through its mode set - tings. to run timer 1 while timer 0 is in mode 3, set the timer 1 mode as 0, 1, or 2. to disable timer 1, configure it for mode 3. figure 18.3. t0 mode 3 block diagram tl0 (8 bits) tmod 0 1 tcon tf0 tr0 tr1 tf1 ie1 it1 ie0 it0 interrupt interrupt 0 1 sysclk pre-scaled clock tr1 th0 (8 bits) t 1 m 1 t 1 m 0 c / t 1 g a t e 1 g a t e 0 c / t 0 t 0 m 1 t 0 m 0 tr0 gate0 in0pl xor /int0 t0 crossbar ckcon t 3 m h t 3 m l s c a 0 s c a 1 t 0 m t 2 m h t 2 m l t 1 m
rev. 1.5 183 c8051f330/1/2/3/4/5 sfr definition 18.1. tcon: timer control bit7: tf1: timer 1 overflow flag. set by hardware when timer 1 overflows. this flag can be cleared by software but is auto- matically cleared when the cpu vectors to the timer 1 interrupt service routine. 0: no timer 1 overflow detected. 1: timer 1 has overflowed. bit6: tr1: timer 1 run control. 0: timer 1 disabled. 1: timer 1 enabled. bit5: tf0: timer 0 overflow flag. set by hardware when timer 0 overflows. this flag can be cleared by software but is auto- matically cleared when the cpu vectors to the timer 0 interrupt service routine. 0: no timer 0 overflow detected. 1: timer 0 has overflowed. bit4: tr0: timer 0 run control. 0: timer 0 disabled. 1: timer 0 enabled. bit3: ie1: external interrupt 1. this flag is set by hardware when an edge/level of type defined by it1 is detected. it can be cleared by software but is automatically cl eared when the cpu vectors to the external interrupt 1 service routine if it1 = 1. when it1 = 0, this flag is set to ?1? when /int1 is active as defined by bit in1pl in register it01cf (see sfr definition 9.11). bit2: it1: interrupt 1 type select. this bit selects whether the co nfigured /int1 interrupt will be edge or level sensitive. /int1 is configured active low or high by the in1pl bit in the it01cf register (see sfr definition 9.11). 0: /int1 is level triggered. 1: /int1 is edge triggered. bit1: ie0: external interrupt 0. this flag is set by hardware when an edge/level of type defined by it0 is detected. it can be cleared by software but is automatically cl eared when the cpu vectors to the external interrupt 0 service routine if it0 = 1. when it0 = 0, this flag is set to ?1? when /int0 is active as defined by bit in0pl in register it01cf (see sfr definition 9.11). bit0: it0: interrupt 0 type select. this bit selects whether the co nfigured /int0 interrupt will be edge or level sensitive. /int0 is configured active low or high by the in0p l bit in register it01cf (see sfr definition 9.11). 0: /int0 is level triggered. 1: /int0 is edge triggered. r/w r/w r/w r/w r/w r/w r/w r/w reset value tf1 tr1 tf0 tr0 ie1 it1 ie0 it0 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: (bit addressable) 0x88
c8051f330/1/2/3/4/5 184 rev. 1.5 sfr definition 18.2. tmod: timer mode bit7: gate1: timer 1 gate control. 0: timer 1 enabled when tr1 = 1 irrespective of /int1 logic level. 1: timer 1 enabled only when tr1 = 1 and /int1 is active as defined by bit in1pl in regis- ter it01cf (see sfr definition 9.11). bit6: c/t1: counter/timer 1 select. 0: timer function: timer 1 incremented by clock defined by t1m bit (ckcon.4). 1: counter function: timer 1 incremented by high-to-low transitions on external input pin (t1). bits5 ? 4: t1m1 ? t1m0: timer 1 mode select. these bits select the timer 1 operation mode. bit3: gate0: timer 0 gate control. 0: timer 0 enabled when tr0 = 1 irrespective of /int0 logic level. 1: timer 0 enabled only when tr0 = 1 and /int0 is active as defined by bit in0pl in regis- ter it01cf (see sfr definition 9.11). bit2: c/t0: counter/timer select. 0: timer function: timer 0 incremented by clock defined by t0m bit (ckcon.3). 1: counter function: timer 0 incremented by high-to-low transitions on external input pin (t0). bits1 ? 0: t0m1 ? t0m0: timer 0 mode select. these bits select the timer 0 operation mode. r/w r/w r/w r/w r/w r/w r/w r/w reset value gate1 c/t1 t1m1 t1m0 gate0 c/t0 t0m1 t0m0 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0x89 t1m1 t1m0 mode 0 0 mode 0: 13-bit counter/timer 0 1 mode 1: 16-bit counter/timer 1 0 mode 2: 8-bit counter/timer with auto-reload 1 1 mode 3: timer 1 inactive t0m1 t0m0 mode 0 0 mode 0: 13-bit counter/timer 0 1 mode 1: 16-bit counter/timer 1 0 mode 2: 8-bit counter/timer with auto-reload 1 1 mode 3: two 8-bit counter/timers
rev. 1.5 185 c8051f330/1/2/3/4/5 sfr definition 18.3. ckcon: clock control bit7: t3mh: timer 3 hi gh byte clock select. this bit selects the clock supplied to the timer 3 high byte if timer 3 is configured in split 8- bit timer mode. t3mh is ignored if time 3 is in any other mode. 0: timer 3 high byte uses the clock defined by the t3xclk bit in tmr3cn. 1: timer 3 high byte uses the system clock. bit6: t3ml: timer 3 lo w byte clock select. this bit selects the clock supplie d to timer 3. if timer 3 is c onfigured in split 8-bit timer mode, this bit selects the clock supplied to the lower 8-bit timer. 0: timer 3 low byte uses the clock defined by the t3xclk bit in tmr3cn. 1: timer 3 low byte uses the system clock. bit5: t2mh: timer 2 hi gh byte clock select. this bit selects the clock supplied to the timer 2 high byte if timer 2 is configured in split 8- bit timer mode. t2mh is ignored if timer 2 is in any other mode. 0: timer 2 high byte uses the clock defined by the t2xclk bit in tmr2cn. 1: timer 2 high byte uses the system clock. bit4: t2ml: timer 2 lo w byte clock select. this bit selects the clock supplie d to timer 2. if timer 2 is c onfigured in split 8-bit timer mode, this bit selects the clock supplied to the lower 8-bit timer. 0: timer 2 low byte uses the clock defined by the t2xclk bit in tmr2cn. 1: timer 2 low byte uses the system clock. bit3: t1m: timer 1 clock select. this select the clock source supplied to timer 1. t1m is ignored when c/t1 is set to logic 1. 0: timer 1 uses the clock defined by the prescale bits, sca1 ? sca0. 1: timer 1 uses the system clock. bit2: t0m: timer 0 clock select. this bit selects the clock source supplied to timer 0. t0m is ignored when c/t0 is set to logic 1. 0: counter/timer 0 uses the clock defined by the prescale bits, sca1 ? sca0. 1: counter/timer 0 uses the system clock. bits1 ? 0: sca1 ? sca0: timer 0/1 prescale bits. these bits control the division of the clock su pplied to timer 0 and/or timer 1 if configured to use prescaled clock inputs. r/w r/w r/w r/w r/w r/w r/w r/w reset value t3mh t3ml t2mh t2ml t1m t0m sca1 sca0 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0x8e sca1 sca0 prescaled clock 0 0 system clock divided by 12 0 1 system clock divided by 4 1 0 system clock divided by 48 1 1 external clock divided by 8 note: external clock divided by 8 is synchronized with the system clock.
c8051f330/1/2/3/4/5 186 rev. 1.5 sfr definition 18.4. tl0: timer 0 low byte sfr definition 18.5. tl1: timer 1 low byte sfr definition 18.6. th0: timer 0 high byte sfr definition 18.7. th1: timer 1 high byte bits 7 ? 0: tl0: timer 0 low byte. the tl0 register is the low byte of the 16-bit timer 0. r/w r/w r/w r/w r/w r/w r/w r/w reset value 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0x8a bits 7 ? 0: tl1: timer 1 low byte. the tl1 register is the low byte of the 16-bit timer 1. r/w r/w r/w r/w r/w r/w r/w r/w reset value 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0x8b bits 7 ? 0: th0: timer 0 high byte. the th0 register is the high byte of the 16-bit timer 0. r/w r/w r/w r/w r/w r/w r/w r/w reset value 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0x8c bits 7 ? 0: th1: timer 1 high byte. the th1 register is the high byte of the 16-bit timer 1. r/w r/w r/w r/w r/w r/w r/w r/w reset value 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0x8d
rev. 1.5 187 c8051f330/1/2/3/4/5 18.2. timer 2 timer 2 is a 16-bit timer formed by two 8-bit sfrs: tmr2l (low byte) and tmr2h (high byte). timer 2 may operate in 16-bit auto-reload mode or (split) 8-bit auto-reload mode. the t2split bit (tmr2cn.3) defines the timer 2 operation mode. timer 2 may be clocked by the system clock, the system clock divided by 12, or the external oscillator source divided by 8. the external clock mode is ideal for real-time clock (rtc) functionality, where the internal oscillator drives t he system clock while timer 2 (and/or the pca) is clocked by an external preci - sion oscillator. note that the external oscillator source divided by 8 is synchronized with the system clock. 18.2.1. 16-bit timer with auto-reload when t2split (tmr2cn. 3) is zero, timer 2 operates as a 16-bit time r with auto-reload. timer 2 can be clocked by sysclk, sysclk divided by 12, or the exte rnal oscillator clock source divided by 8. as the 16-bit timer register increments and overflows from 0xffff to 0x0000, the 16-bit value in the timer 2 reload registers (tmr2rlh and tmr2rll) is loaded into the timer 2 register as shown in figure 18.4 , and the timer 2 high byte overflow flag (tmr2cn.7) is set. if timer 2 interrupts are enabled (if ie.5 is set), an interrupt will be gen erated on each timer 2 overflow. additionally, if timer 2 interrupts are enabled and the tf2len bit is set (tmr2cn. 5), an interr upt will be generated each time the lower 8 bits (tmr2l) overflow from 0xff to 0x00. figure 18.4. timer 2 16-bi t mode block diagram external clock / 8 sysclk / 12 sysclk tmr2l tmr2h tmr2rll tmr2rlh reload tclk 0 1 tr2 tmr2cn t2split tf2cen tf2l tf2h t2xclk tr2 0 1 t2xclk interrupt tf2len to adc, smbus to smbus tl2 overflow ckcon t 3 m h t 3 m l s c a 0 s c a 1 t 0 m t 2 m h t 2 m l t 1 m
c8051f330/1/2/3/4/5 188 rev. 1.5 18.2.2. 8-bit timers with auto-reload when t2split is set, timer 2 operates as two 8-bit timers (tmr2h and tmr2l). both 8-bit timers oper - ate in auto-reload mode as shown in figure 18.5 . tmr2rll holds the reload value for tmr2l; tmr2rlh holds the reload value for tmr2h. the tr2 bit in tmr2cn handles the run control for tmr2h. tmr2l is always running when configured for 8-bit mode. each 8-bit timer may be c onfigured to use sysclk, sysclk divided by 12, or the external oscillator clock source divided by 8. the timer 2 clock select bits (t2mh and t2ml in ckcon) select either sysclk or the clock defined by the timer 2 external clock select bit (t 2xclk in tmr2cn), as follows: the tf2h bit is set when tmr2h overflows from 0xff to 0x00; the tf2l bit is set when tmr2l overflows from 0xff to 0x00. when timer 2 interrupts are enabled (ie.5), an interrupt is generated each time tmr2h overflows. if timer 2 interrupts are enabled and tf2len (tmr2cn.5) is set, an interrupt is gener - ated each time either tmr2l or tmr2h overflows. when tf2len is enabled, software must check the tf2h and tf2l flags to determine the source of the timer 2 interrupt. the tf2h and tf2l interrupt flags are not cleared by hardware and must be manually cleared by software. figure 18.5. timer 2 8- bit mode block diagram t2mh t2xclk tmr2h clock source t2ml t2xclk tmr2l clock source 0 0 sysclk / 12 0 0 sysclk / 12 0 1 external clock / 8 0 1 external clock / 8 1 x sysclk 1 x sysclk sysclk tclk 0 1 tr2 external clock / 8 sysclk / 12 0 1 t2xclk 1 0 tmr2h tmr2rlh reload reload tclk tmr2l tmr2rll interrupt tmr2cn t2split tf2cen tf2len tf2l tf2h t2xclk tr2 to adc, smbus to smbus ckcon t 3 m h t 3 m l s c a 0 s c a 1 t 0 m t 2 m h t 2 m l t 1 m
rev. 1.5 189 c8051f330/1/2/3/4/5 sfr definition 18.8. tmr2cn: timer 2 control bit7: tf2h: timer 2 high byte overflow flag. set by hardware when the timer 2 high byte ov erflows from 0xff to 0x00. in 16 bit mode, this will occur when timer 2 overflows from 0x ffff to 0x0000. when the timer 2 interrupt is enabled, setting this bit causes the cpu to vector to the timer 2 interrupt service routine. tf2h is not automatically cleared by hard ware and must be cleared by software. bit6: tf2l: timer 2 low byte overflow flag. set by hardware when the timer 2 low byte over flows from 0xff to 0x00. when this bit is set, an interrupt will be generat ed if tf2len is set and timer 2 interrupts are enabled. tf2l will set when the low byte overflows regardless of the timer 2 mode. this bit is not automat- ically cleared by hardware. bit5: tf2len: timer 2 low byte interrupt enable. this bit enables/disables timer 2 low byte in terrupts. if tf2len is set and timer 2 inter- rupts are enabled, an interrupt will be generated when the lo w byte of timer 2 overflows. 0: timer 2 low byte interrupts disabled. 1: timer 2 low byte interrupts enabled. bit4: tf2cen: timer 2 low-frequen cy oscillator capture enable. this bit enables/disables timer 2 low-frequency oscillator capture mode. if tf2cen is set and timer 2 interrupts are enabled, an in terrupt will be generated on a falling edge of the low-frequency oscillator output, and the current 16 -bit timer value in tmr2h:tmr2l will be copied to tmr2rlh:tmr2rll. see section ?13. oscillators? on page 115 for more details. 0: timer 2 low-frequency oscillator capture disabled. 1: timer 2 low-frequency oscillator capture enabled. bit3: t2split: timer 2 split mode enable. when this bit is set, timer 2 operates as two 8-bit timers with auto-reload. 0: timer 2 operates in 16-bit auto-reload mode. 1: timer 2 operates as two 8-bit auto-reload timers. bit2: tr2: timer 2 run control. this bit enables/disables timer 2. in 8-bit mode, this bit enables/disables tmr2h only; tmr2l is always enabled in this mode. 0: timer 2 disabled. 1: timer 2 enabled. bit1: unused. read = 0b . write = don?t care. bit0: t2xclk: timer 2 external clock select. this bit selects the external cl ock source for timer 2. if timer 2 is in 8-bit mode, this bit selects the external o scillator clock source fo r both timer bytes. however, the timer 2 clock select bits (t2mh and t2ml in register ck con) may still be used to select between the external clock and the system clock for either timer. 0: timer 2 external clock selection is the system clock divided by 12. 1: timer 2 external clock selection is the external clock divided by 8. note that the external oscillator source divided by 8 is synchronized with the system clock. r/w r/w r/w r/w r/w r/w r r/w reset value tf2h tf2l tf2len tf2cen t2split tr2 ? t2xclk 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: (bit addressable) 0xc8
c8051f330/1/2/3/4/5 190 rev. 1.5 sfr definition 18.9. tmr2rll: timer 2 relo ad register low byte sfr definition 18.10. tmr2rlh: timer 2 relo ad register high byte sfr definition 18.11. tmr2l: timer 2 low byte sfr definition 18.12. tmr2h timer 2 high byte bits 7 ? 0: tmr2rll: timer 2 reload register low byte. tmr2rll holds the low byte of the reload value for timer 2. r/w r/w r/w r/w r/w r/w r/w r/w reset value 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xca bits 7 ? 0: tmr2rlh: timer 2 reload register high byte. the tmr2rlh holds the high byte of the reload value for timer 2. r/w r/w r/w r/w r/w r/w r/w r/w reset value 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xcb bits 7 ? 0: tmr2l: timer 2 low byte. in 16-bit mode, the tmr2l register contains the low byte of the 16-bit timer 2. in 8-bit mode, tmr2l contains the 8-bit low byte timer value. r/w r/w r/w r/w r/w r/w r/w r/w reset value 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xcc bits 7 ? 0: tmr2h: timer 2 high byte. in 16-bit mode, the tmr2h register contains t he high byte of the 16-bit timer 2. in 8-bit mode, tmr2h contains the 8-bit high byte timer value. r/w r/w r/w r/w r/w r/w r/w r/w reset value 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xcd
rev. 1.5 191 c8051f330/1/2/3/4/5 18.3. timer 3 timer 3 is a 16-bit timer formed by two 8-bit sfrs: tmr3l (low byte) and tmr3h (high byte). timer 3 may operate in 16-bit auto-reload mode or (split) 8-bit auto-reload mode. the t3split bit (tmr3cn.3) defines the timer 3 operation mode. timer 3 may be clocked by the system clock, the system clock divided by 12, or the external oscillator source divided by 8. the external clock mode is ideal for real-time clock (rtc) functionality, where the internal oscillator drives t he system clock while timer 3 (and/or the pca) is clocked by an external preci - sion oscillator. note that the external oscillator source divided by 8 is synchronized with the system clock. 18.3.1. 16-bit timer with auto-reload when t3split (tmr3cn.3) is zero, timer 3 operates as a 16-bit timer with auto-reload. timer 3 can be clocked by sysclk, sysclk divided by 12, or the exte rnal oscillator clock source divided by 8. as the 16-bit timer register increments and overflows from 0xffff to 0x0000, the 16-bit value in the timer 3 reload registers (tmr3rlh and tmr3rll) is load ed into the timer 3 register as shown in figure 18.6 , and the timer 3 high byte overflow flag (tmr3cn.7) is set. if timer 3 interrupts are enabled (if eie1.7 is set), an interrupt will be generat ed on each timer 3 overflow. additiona lly, if timer 3 inte rrupts are enabled and the tf3len bit is set (tmr3cn. 5), an interr upt will be generated each time the lower 8 bits (tmr3l) overflow from 0xff to 0x00. figure 18.6. timer 3 16-bi t mode block diagram external clock / 8 sysclk / 12 sysclk tmr3l tmr3h tmr3rll tmr3rlh reload tclk 0 1 tr3 tmr3cn t3split tf3cen tf3l tf3h t3xclk tr3 0 1 t3xclk interrupt tf3len to adc ckcon t 3 m h t 3 m l s c a 0 s c a 1 t 0 m t 2 m h t 2 m l t 1 m
c8051f330/1/2/3/4/5 192 rev. 1.5 18.3.2. 8-bit timers with auto-reload when t3split is set, timer 3 operates as two 8-bi t timers (tmr3h and tmr3l). both 8-bit timers oper - ate in auto-reload mode as shown in figure 18.7 . tmr3rll holds the reload value for tmr3l; tmr3rlh holds the reload value for tmr3h. the tr3 bit in tmr3cn handles the run control for tmr3h. tmr3l is always running when configured for 8-bit mode. each 8-bit timer may be c onfigured to use sysclk, sysclk divided by 12, or the external oscillator clock source divided by 8. the timer 3 clo ck select bits (t3mh and t3ml in ckcon) select either sysclk or the clock defined by the timer 3 external cloc k select bit (t3xclk in tmr3cn), as follows: the tf3h bit is set when tmr3h overflows from 0xff to 0x00; the tf3l bit is set when tmr3l overflows from 0xff to 0x00. when timer 3 interrupts are enabled, an interrupt is generated each time tmr3h over - flows. if timer 3 interrupts are enabled and tf3len (tmr3cn.5) is set, an interrupt is generated each time either tmr3l or tmr3h overflows. when tf3le n is enabled, software must check the tf3h and tf3l flags to determine the source of the timer 3 interrupt. the tf3h and tf3l interrupt flags are not cleared by hardware and must be manually cleared by software. figure 18.7. timer 3 8- bit mode block diagram t3mh t3xclk tmr3h clock source t3ml t3xclk tmr3l clock source 0 0 sysclk / 12 0 0 sysclk / 12 0 1 external clock / 8 0 1 external clock / 8 1 x sysclk 1 x sysclk sysclk tclk 0 1 tr3 external clock / 8 sysclk / 12 0 1 t3xclk 1 0 tmr3h tmr3rlh reload reload tclk tmr3l tmr3rll interrupt tmr3cn t3split tf3cen tf3len tf3l tf3h t3xclk tr3 to adc ckcon t 3 m h t 3 m l s c a 0 s c a 1 t 0 m t 2 m h t 2 m l t 1 m
rev. 1.5 193 c8051f330/1/2/3/4/5 sfr definition 18.13. tmr3cn: timer 3 control bit7: tf3h: timer 3 high byte overflow flag. set by hardware when the timer 3 high byte ov erflows from 0xff to 0x00. in 16 bit mode, this will occur when timer 3 overflows from 0xff ff to 0x0000. when the timer 3 inte rrupt is enabled, setting this bit causes the cpu to vector to the timer 3 interrupt service routine. tf3h is not automatically cleared by hard ware and must be cleared by software. bit6: tf3l: timer 3 low byte overflow flag. set by hardware when the timer 3 low byte over flows from 0xff to 0x00. when this bit is set, an interrupt will be generated if tf3len is set and timer 3 interr upts are enabled. tf3l will set when the low byte overflow s regardless of the timer 3 mo de. this bit is not automat- ically cleared by hardware. bit5: tf3len: timer 3 low byte interrupt enable. this bit enables/disables timer 3 low byte in terrupts. if tf3len is set and timer 3 inter- rupts are enabled, an interrupt will be generated when the lo w byte of timer 3 overflows. 0: timer 3 low byte interrupts disabled. 1: timer 3 low byte interrupts enabled. bit4: tf3cen: timer 3 low-frequen cy oscillator capture enable. this bit enables/disables timer 3 low-frequency oscillator capture mode. if tf3cen is set and timer 3 interrupts are enabled, an in terrupt will be generated on a rising edge of the low-frequency oscillator output, and the current 16 -bit timer value in tmr3h:tmr3l will be copied to tmr3rlh:tmr3rll. see section ?13. oscillators? on page 115 for more details. 0: timer 3 low-frequency oscillator capture disabled. 1: timer 3 low-frequency oscillator capture enabled. bit3: t3split: timer 3 split mode enable. when this bit is set, timer 3 operates as two 8-bit timers with auto-reload. 0: timer 3 operates in 16-bit auto-reload mode. 1: timer 3 operates as two 8-bit auto-reload timers. bit2: tr3: timer 3 run control. this bit enables/disables timer 3. in 8-bit mode, this bit enables/disables tmr3h only; tmr3l is always enabled in this mode. 0: timer 3 disabled. 1: timer 3 enabled. bit1: unused. read = 0b . write = don?t care. bit0: t3xclk: timer 3 external clock select. this bit selects the external cl ock source for timer 3. if timer 3 is in 8-bit mode, this bit selects the external o scillator clock source for both time r bytes. however, the timer 3 clock select bits (t3mh and t3ml in register ck con) may still be used to select between the external clock and the system clock for either timer. 0: timer 3 external clock selection is the system clock divided by 12. 1: timer 3 external clock selection is the external clock divided by 8. note that the external oscillator source divided by 8 is synchronized with the system clock. r/w r/w r/w r/w r/w r/w r r/w reset value tf3h tf3l tf3len tf3cen t3split tr3 ? t3xclk 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0x91
c8051f330/1/2/3/4/5 194 rev. 1.5 sfr definition 18.14. tmr3rll: timer 3 reload register low byte sfr definition 18.15. tmr3rlh: timer 3 relo ad register high byte sfr definition 18.16. tmr3l: timer 3 low byte sfr definition 18.17. tmr3h timer 3 high byte bits 7 ? 0: tmr3rll: timer 3 reload register low byte. tmr3rll holds the low byte of the reload value for timer 3. r/w r/w r/w r/w r/w r/w r/w r/w reset value 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0x92 bits 7 ? 0: tmr3rlh: timer 3 reload register high byte. the tmr3rlh holds the high byte of the reload value for timer 3. r/w r/w r/w r/w r/w r/w r/w r/w reset value 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0x93 bits 7 ? 0: tmr3l: timer 3 low byte. in 16-bit mode, the tmr3l register contains the low byte of the 16-bit timer 3. in 8-bit mode, tmr3l contains the 8-bit low byte timer value. r/w r/w r/w r/w r/w r/w r/w r/w reset value 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0x94 bits 7 ? 0: tmr3h: timer 3 high byte. in 16-bit mode, the tmr3h register contains t he high byte of the 16-bit timer 3. in 8-bit mode, tmr3h contains the 8-bit high byte timer value. r/w r/w r/w r/w r/w r/w r/w r/w reset value 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0x95
rev. 1.5 195 c8051f330/1/2/3/4/5 19. programmable counter array the programmable counter array (pca0) provides enhanced timer functionality while requiring less cpu intervention than the standard 8051 counter/timers. th e pca consists of a dedicated 16-bit counter/timer and three 16-bit capture/compare modules. each capt ure/compare module has its own associated i/o line (cexn) which is routed through the crossbar to port i/o when enabled (see section ?14.1. priority crossbar decoder? on page 127 for details on configuring the crossbar). the counter/timer is driven by a programmable timebase that can select between six so urces: system clock, system clock divided by four, system clock divided by twelve, the external oscillator clock source divided by 8, timer 0 overflow, or an external clock signal on the eci input pin. each capture/compare module may be configured to operate independently in one of six modes: edge-triggered capture, software timer, high-speed output, fre - quency output, 8-bit pwm, or 16-bit pwm (each mode is described in section ?19.2. capture/compare modules? on page 197 ). the external oscillator clock option is i deal for real-time clock (rtc) functionality, allowing the pca to be clocked by a precision external oscill ator while the internal oscillator drives the sys - tem clock. the pca is configured and controlled th rough the system controller's special function regis - ters. the pca block diagram is shown in figure 19.1 important note: the pca module 2 may be used as a watchdog timer (wdt), and is enabled in this mode following a system reset. access to certain pca registers is restricted while wdt mode is enabled . see section 19.3 for details. figure 19.1. pca block diagram capture/compare module 1 capture/compare module 0 capture/compare module 2 / wdt cex1 eci crossbar cex2 cex0 port i/o 16-bit counter/timer pca clock mux sysclk/12 sysclk/4 timer 0 overflow eci sysclk external clock/8
c8051f330/1/2/3/4/5 196 rev. 1.5 19.1. pca counter/timer the 16-bit pca counter/timer consists of two 8-bi t sfrs: pca0l and pca0h. pca0h is the high byte (msb) of the 16-bit counter/timer and pca0l is the lo w byte (lsb). reading pc a0l automatically latches the value of pca0h into a ?snapshot? register; the following pca0h read accesses this ?snapshot? register. reading the pca0l register first guarantees an accu rate reading of the entire 16-bit pca0 counter. reading pca0h or pca0l does not disturb the counter operation. the cps2 ? cps0 bits in the pca0md register select the timebase for the counter/timer as shown in ta b l e 19.1 . when the counter/timer overflows from 0xffff to 0x0 000, the counter overflow fl ag (cf) in pca0md is set to logic 1 and an interrupt request is generated if cf interrupts are enabled. setting the ecf bit in pca0md to logic 1 enables the cf flag to generate an interrupt request. the cf bit is not automatically cleared by hardware when the cpu vectors to the in terrupt service routine, and must be cleared by soft - ware (note: pca0 interrupts must be globally enabled before cf interrupts are recognized. pca0 inter - rupts are globally enabled by setting the ea bit (ie.7) and the epca0 bit in eie1 to logic 1). clearing the cidl bit in the pca0md register a llows the pca to continue normal op eration while the cpu is in idle mode. figure 19.2. pca counter /timer block diagram table 19.1. pca timebase input options cps2 cps1 cps0 timebase 0 0 0 system clock divided by 12 0 0 1 system clock divided by 4 0 1 0 timer 0 overflow 011 high-to-low transitions on eci (max rate = system clock divided by 4) 100system clock 101 external oscillator source divided by 8 * *note: external oscillator source divided by 8 is synchronized with the system clock. pca0cn c f c r c c f 0 c c f 2 c c f 1 c c f 4 c c f 3 pca0md c i d l w d t e e c f c p s 1 c p s 0 w d l c k c p s 2 idle 0 1 pca0h pca0l snapshot register to sfr bus overflow to pca interrupt system cf pca0l read to pca modules sysclk/12 sysclk/4 timer 0 overflow eci 000 001 010 011 100 101 sysclk external clock/8
rev. 1.5 197 c8051f330/1/2/3/4/5 19.2. capture/compare modules each module can be configured to operate independently in one of six operation modes: edge-triggered capture, software timer, high speed output, frequency output, 8-bit pulse width modulator, or 16-bit pulse width modulator. each module has special func tion registers (sfrs) asso ciated with it in the cip- 51 system controller. these registers are used to exchange data with a module and configure the module's mode of operation. ta b l e 19.2 summarizes the bit settings in the pca0cpmn registers used to select the pca capture/com - pare module?s operating modes. setting the eccfn bi t in a pca0cpmn register enables the module's ccfn interrupt. note: pca0 interrupts must be globally enabled before individual ccfn interrupts are rec - ognized. pca0 interrupts are globally enabled by se tting the ea bit and the epca0 bit to logic 1. see figure 19.3 for details on the pca interrupt configuration. figure 19.3. pca interrupt block diagram table 19.2. pca0cpm register settings fo r pca capture/compare modules pwm16 ecom capp capn mat tog pwm eccf operation mode x x 10000x capture triggered by positive edge on cexn x x 01000x capture triggered by negative edge on cexn x x 11000x capture triggered by transition on cexn x 1 00100xsoftware timer x 1 00110xhigh speed output x 1 0 0 x 1 1 x frequency output 0 1 0 0 x 0 1 x 8-bit pulse width modulator 1 1 0 0 x 0 1 x 16-bit pulse width modulator note: x = don?t care. pca0cn c f c r c c f 0 c c f 2 c c f 1 pca0md c i d l w d t e e c f c p s 1 c p s 0 w d l c k c p s 2 0 1 pca module 0 (ccf0) pca module 1 (ccf1) eccf1 0 1 eccf0 0 1 pca module 2 (ccf2) eccf2 pca counter/ timer overflow 0 1 interrupt priority decoder epca0 0 1 ea 0 1 pca0cpmn (for n = 0 to 2) p w m 1 6 n e c o m n e c c f n t o g n p w m n c a p p n c a p n n m a t n
c8051f330/1/2/3/4/5 198 rev. 1.5 19.2.1. edge-triggered capture mode in this mode, a valid transition on the cexn pi n causes the pca to capture the value of the pca counter/timer and load it into the corresponding mo dule's 16-bit capture/compar e register (pca0cpln and pca0cphn). the cappn and capnn bits in the pca0cpmn register are used to select the type of transi - tion that triggers the capture: low-to-high transition (p ositive edge), high-to-low transition (negative edge), or either transition (positive or negative edge). when a capture occurs, the capture/compare flag (ccfn) in pca0cn is set to logic 1 and an interrupt request is generated if ccf interrupts are enabled. the ccfn bit is not automatically cleared by hardware when th e cpu vectors to the interrupt service routine, and must be cleared by softwa re. if both cappn and capn n bits are set to logic 1, then the state of the port pin associated with cexn can be read directly to de termine whether a rising-edge or falling-edge caused the capture. figure 19.4. pca capture mode diagram note: the cexn input signal must remain high or low for at least 2 system clock cycles to be recognized by the hardware. pca0l pca0cpln pca timebase cexn crossbar port i/o pca0h capture pca0cphn 0 1 0 1 (to ccfn) pca0cpmn p w m 1 6 n e c o m n e c c f n t o g n p w m n c a p p n c a p n n m a t n pca0cn c f c r c c f 0 c c f 2 c c f 1 c c f 4 c c f 3 pca interrupt 0x00x x
rev. 1.5 199 c8051f330/1/2/3/4/5 19.2.2. software timer (compare) mode in software timer mode, the pca c ounter/timer value is compared to the module's 16-bit capture/compare register (pca0cphn and pca0cpln). when a match occurs, the capture/compare flag (ccfn) in pca0cn is set to logic 1 and an interrupt request is generated if ccf interrupts are enabled. the ccfn bit is not automatically cleared by hard ware when the cpu vectors to the interrupt service routine, and must be cleared by software. setting the ecomn and matn bits in the pca0cpmn register enables software timer mode. important note about capture/compare registers : when writing a 16-bit value to the pca0 cap - ture/compare registers, the low byte should alwa ys be written first. writing to pca0cpln clears the ecomn bit to ?0?; writing to pca0cphn sets ecomn to ?1?. figure 19.5. pca software timer mode diagram match 16-bit comparator pca0h pca0cphn enable pca0l pca timebase pca0cpln 00 00 0 1 x enb enb 0 1 write to pca0cpln write to pca0cphn reset pca0cpmn p w m 1 6 n e c o m n e c c f n t o g n p w m n c a p p n c a p n n m a t n x pca0cn c f c r c c f 0 c c f 2 c c f 1 c c f 4 c c f 3 pca interrupt
c8051f330/1/2/3/4/5 200 rev. 1.5 19.2.3. high-speed output mode in high-speed output mode, a module?s associated cexn pin is toggled each time a match occurs between the pca counter and the module's 16- bit capture/compare register (pca0cphn and pca0cpln) setting the togn, matn, and ecomn bits in the pca0cpmn register enables the high- speed output mode. important note about capture/compare registers : when writing a 16-bit value to the pca0 cap - ture/compare registers, the low byte should alwa ys be written first. writing to pca0cpln clears the ecomn bit to ?0?; writing to pca0cphn sets ecomn to ?1?. figure 19.6. pca high-spee d output mode diagram match 16-bit comparator pca0h pca0cphn enable pca0l pca timebase pca0cpln 0 1 00 0x enb enb 0 1 write to pca0cpln write to pca0cphn reset pca0cpmn p w m 1 6 n e c o m n e c c f n t o g n p w m n c a p p n c a p n n m a t n x cexn crossbar port i/o toggle 0 1 togn pca0cn c f c r c c f 0 c c f 2 c c f 1 c c f 4 c c f 3 pca interrupt
rev. 1.5 201 c8051f330/1/2/3/4/5 19.2.4. frequency output mode frequency output mode produces a programmable-freq uency square wave on the module?s associated cexn pin. the capture/compare module high byte holds the number of pca clocks to count before the out - put is toggled. the frequency of the square wave is then defined by equation 19.3 . equation 19.3. square wave fr equency output where f pca is the frequency of the clock selected by the cps2 ? 0 bits in the pca mode register, pca0md. the lower byte of the capture/compare modu le is compared to the pca counter low byte; on a match, cexn is toggled and the offset held in the hi gh byte is added to the matched value in pca0cpln. frequency output mode is enabled by setting the ecomn, togn, and pwmn bits in the pca0cpmn reg - ister. figure 19.7. pca frequency output mode f cexn f pca 2 pca 0 cphn ------------------- --------------------- - = note: a value of 0x00 in the pca0cphn re gister is equal to 256 for this equation. 8-bit comparator pca0l enable pca timebase match pca0cphn 8-bit adder pca0cpln adder enable cexn crossbar port i/o toggle 0 1 togn 000 x pca0cpmn p w m 1 6 n e c o m n e c c f n t o g n p w m n c a p p n c a p n n m a t n x enb enb 0 1 write to pca0cpln write to pca0cphn reset
c8051f330/1/2/3/4/5 202 rev. 1.5 19.2.5. 8-bit pulse width modulator mode each module can be used independently to generate a pulse width modulated (pwm) output on its associ - ated cexn pin. the frequency of the output is depe ndent on the timebase for the pca counter/timer. the duty cycle of the pwm output signal is varied using the module's pca0cpln capture/compare register. when the value in the low byte of the pca counter/ti mer (pca0l) is equal to the value in pca0cpln, the output on the cexn pin will be se t. when the count value in pca0l overflows, the cexn output will be reset (see figure 19.8 ). also, when the counter/timer low byte (pca0l) overflows from 0xff to 0x00, pca0cpln is reloaded automatically with the value stored in the module?s capture/compare high byte (pca0cphn) without software intervention. setting t he ecomn and pwmn bits in the pca0cpmn register enables 8-bit pulse width modulator mode. the duty cycle for 8-bit pwm mode is given by equation 19.4 . important note about capture/compare registers : when writing a 16-bit value to the pca0 cap - ture/compare registers, the low byte should alwa ys be written first. writing to pca0cpln clears the ecomn bit to ?0?; writing to pca0cphn sets ecomn to ?1?. equation 19.4. 8-bit pwm duty cycle using equation 19.4 , the largest duty cycle is 100% (pca0cph n = 0), and the smallest duty cycle is 0.39% (pca0cphn = 0xff). a 0% duty cycle may be generated by clearing the ecomn bit to ?0?. figure 19.8. pca 8-bi t pwm mode diagram dutycycle 256 pca 0 cphn ? () 256 ------------------ ----------------- ---------------- = 8-bit comparator pca0l pca0cpln pca0cphn cexn crossbar port i/o enable overflow pca timebase 00x0 x q q set clr s r match pca0cpmn p w m 1 6 n e c o m n e c c f n t o g n p w m n c a p p n c a p n n m a t n 0 enb enb 0 1 write to pca0cpln write to pca0cphn reset
rev. 1.5 203 c8051f330/1/2/3/4/5 19.2.6. 16-bit pulse width modulator mode a pca module may also be operated in 16-bit pwm mode. in this mode, the 16-bit capture/compare mod - ule defines the number of pca clocks for the low time of the pwm signal. when the pca counter matches the module contents, the output on cexn is asserted high; when the counter over flows, cexn is asserted low. to output a varying duty cycle, new value wr ites should be synchroniz ed with pca ccfn match inter - rupts. 16-bit pwm mode is enabled by setting the ecomn, pwmn, and pwm16n bits in the pca0cpmn register. for a varying duty cycle, match interrupts should be enabled (eccfn = 1 and matn = 1) to help synchronize the capture/co mpare register writes. the duty cycle for 16-bit pwm mode is given by equation 19.5 . important note about capture/compare registers : when writing a 16-bit value to the pca0 cap - ture/compare registers, the low byte should alwa ys be written first. writing to pca0cpln clears the ecomn bit to ?0?; writing to pca0cphn sets ecomn to ?1?. equation 19.5. 16-bit pwm duty cycle using equation 19.5 , the largest duty cycle is 100% (pca0cpn = 0), and the smallest duty cycle is 0.0015% (pca0cpn = 0xffff). a 0% duty cycle may be generated by clearing the ecomn bit to ?0?. figure 19.9. pca 16-bit pwm mode 19.3. watchdog timer mode a programmable watchdog timer (wdt) function is avai lable through the pca module 2. the wdt is used to generate a reset if the time between writes to th e wdt update register (pca0cph2) exceed a specified limit. the wdt can be configured and enabled/disabled as needed by software. with the wdte bit set in the pca0md register, modu le 2 operates as a watchdog timer (wdt). the mod - ule 2 high byte is compared to the pca counter high byte; the module 2 low byte holds the offset to be used when wdt updates are performed. the watchdog timer is enabled on reset. writes to some pca registers are restricted while the watchdog timer is enabled. dutycycle 65536 pca 0 cpn ? () 65536 ------------------ ------------------ ---------------- - = pca0cpln pca0cphn enable pca timebase 00x0 x pca0cpmn p w m 1 6 n e c o m n e c c f n t o g n p w m n c a p p n c a p n n m a t n 1 16-bit comparator cexn crossbar port i/o overflow q q set clr s r match pca0h pca0l enb enb 0 1 write to pca0cpln write to pca0cphn reset
c8051f330/1/2/3/4/5 204 rev. 1.5 19.3.1. watchdog timer operation while the wdt is enabled: ? pca counter is forced on. ? writes to pca0l and pca0h are not allowed. ? pca clock source bits (cps2 ? cps0) are frozen. ? pca idle control bi t (cidl) is frozen. ? module 2 is forced in to software timer mode. ? writes to the module 2 mode register (pca0cpm2) are disabled. while the wdt is enabled, writes to the cr bit will not change the pca counter state; the counter will run until the wdt is disabled. the pca co unter run co ntrol (cr) will read zero if the wdt is enabled but user software has not enabled the pca counter. if a ma tch occurs between pca0cph2 and pca0h while the wdt is enabled, a reset will be gener ated. to prevent a wdt reset, the wdt may be updated with a write of any value to pca0cph2. upon a pca0cph2 write, pca0h plus the offset held in pca0cpl2 is loaded into pca0cph2 (see figure 19.10 ). figure 19.10. pca module 2 wi th watchdog timer enabled pca0h enable pca0l overflow reset pca0cpl2 8-bit adder pca0cph2 adder enable pca0md c i d l w d t e e c f c p s 1 c p s 0 w d l c k c p s 2 match write to pca0cph2 8-bit comparator
rev. 1.5 205 c8051f330/1/2/3/4/5 note that the 8-bit offset held in pca0cph2 is comp ared to the upper byte of the 16-bit pca counter. this offset value is the number of pca0l overflows before a reset. up to 256 pca clocks may pass before the first pca0l overflow occurs, depending on the valu e of the pca0l when the update is performed. the total offset is then given (in pca clocks) by equation 19.6 , where pca0l is the value of the pca0l register at the time of the update. equation 19.6. watchdog timer offset in pca clocks the wdt reset is generated when pca0l overflow s while there is a match between pca0cph2 and pca0h. software may force a wdt reset by writing a ?1? to the ccf2 flag (pca0cn.2) while the wdt is enabled. 19.3.2. watchdog timer usage to configure the wdt, perform the following tasks: ? disable the wdt by writing a ?0? to the wdte bit. ? select the desired pca cl ock source (with the cps2 ? cps0 bits). ? load pca0cpl2 with the desi red wdt update offset value. ? configure the pca idle mode (set cidl if the wdt should be suspended while the cpu is in idle mode). ? enable the wdt by setting the wdte bit to ?1?. the pca clock source and idle mode select cannot be changed while the wdt is enabled. the watchdog timer is enabled by setting the wdte or wdlck bits in the pca0md register. when wdlck is set, the wdt cannot be disabled until the next system reset. if wdlck is not set, the wdt is disabled by clearing the wdte bit. the wdt is enabled following any rese t. the pca0 counter clock defaults to the system clock divided by 12, pca0l defaults to 0x00, and pca0cpl2 defaults to 0x00. using equation 19.6 , this results in a wdt timeout interval of 256 pca clock cycles, or 3072 system clock cycles. ta b l e 19.4 lists some example tim - eout intervals for ty pical system clocks. offset 256 pca 0 cpl 2 () 256 pca 0 l ? () + =
c8051f330/1/2/3/4/5 206 rev. 1.5 19.5. register descriptions for pca following are detailed descriptions of the special func tion registers related to the operation of the pca. table 19.4. watchdog timer timeout intervals 1 system clock (hz) pca0cpl2 timeout interval (ms) 24,500,000 255 32.1 24,500,000 128 16.2 24,500,000 32 4.1 18,432,000 255 42.7 18,432,000 128 21.5 18,432,000 32 5.5 11,059,200 255 71.1 11,059,200 128 35.8 11,059,200 32 9.2 3,062,500 2 255 257 3,062,500 2 128 129.5 3,062,500 2 32 33.1 32,000 255 24576 32,000 128 12384 32,000 32 3168 notes: 1. assumes sysclk/12 as the pca clock source, and a pca0l value of 0x00 at the update time. 2. internal sysclk reset frequency = internal oscillator divided by 8.
rev. 1.5 207 c8051f330/1/2/3/4/5 sfr definition 19.1. pca0cn: pca control bit7: cf: pca counter/timer overflow flag. set by hardware when the pca counter/timer overflows from 0xffff to 0x0000. when the counter/timer overflow (cf) inte rrupt is enabled, setting this bit causes the cpu to vector to the pca interrupt service routine. this bi t is not automatically cleared by hardware and must be cleared by software. bit6: cr: pca counter/ timer run control. this bit enables/disables the pca counter/timer. 0: pca counter/timer disabled. 1: pca counter/timer enabled. bits5 ? 3: unused. read = 000b, write = don't care. bit2: ccf2: pca module 2 capture/compare flag. this bit is set by hardware when a match or capture occurs. when t he ccf2 interrupt is enabled, setting this bit causes the cpu to vect or to the pca interrupt service routine. this bit is not automatically cleared by hard ware and must be cleared by software. bit1: ccf1: pca module 1 capture/compare flag. this bit is set by hardware when a match or capture occurs. when t he ccf1 interrupt is enabled, setting this bit causes the cpu to vect or to the pca interrupt service routine. this bit is not automatically cleared by hard ware and must be cleared by software. bit0: ccf0: pca module 0 capture/compare flag. this bit is set by hardware when a match or capture occurs. when t he ccf0 interrupt is enabled, setting this bit causes the cpu to vect or to the pca interrupt service routine. this bit is not automatically cleared by hard ware and must be cleared by software. r/w r/w r r r r/w r/w r/w reset value cf cr - - - ccf2 ccf1 ccf0 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 bit addressable sfr address: 0xd8
c8051f330/1/2/3/4/5 208 rev. 1.5 sfr definition 19.2. pca0md: pca mode bit7: cidl: pca counte r/timer idle control. specifies pca behavior wh en cpu is in idle mode. 0: pca continues to function normally while the system controller is in idle mode. 1: pca operation is suspended while the system controller is in idle mode. bit6: wdte: watchdog timer enable if this bit is set, pca module 2 is used as the watchdog timer. 0: watchdog timer disabled. 1: pca module 2 enabled as watchdog timer. bit5: wdlck: watchdog timer lock this bit locks/unlocks the watchdog timer en able. when wdlck is set, the watchdog timer may not be disabled until the next system reset. 0: watchdog timer enable unlocked. 1: watchdog timer enable locked. bit4: unused. read = 0b, write = don't care. bits3 ? 1: cps2 ? cps0: pca counter/ti mer pulse select. these bits select the timebase source for the pca counter . bit0: ecf: pca counter/timer overflow interrupt enable. this bit sets the masking of the pca co unter/timer overflow (cf) interrupt. 0: disable the cf interrupt. 1: enable a pca counter/timer overflow interrupt request when cf (pca0cn.7) is set. note: when the wdte bit is set to ?1?, the pca0 md register cannot be modified. to change the contents of the pca0md register, the watchdog timer must first be disabled. r/w r/w r/w r r/w r/w r/w r/w reset value cidl wdte wdlck ? cps2 cps1 cps0 ecf 01000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 bit addressable sfr address: 0xd9 cps2 cps1 cps0 timebase 0 0 0 system clock divided by 12 0 0 1 system clock divided by 4 0 1 0 timer 0 overflow 011 high-to-low transitions on eci (max rate = system clock divided by 4) 1 0 0 system clock 1 0 1 external clock divided by 8* 1 1 0 reserved 1 1 1 reserved *note: external oscillator source divided by 8 is synchronized with the system clock.
rev. 1.5 209 c8051f330/1/2/3/4/5 sfr definition 19.3. pca0cpmn: pca capture/compare mode bit7: pwm16n: 16-bit pulse width modulation enable. this bit selects 16-bit mode when pulse width modulation mode is enabled (pwmn = 1). 0: 8-bit pwm selected. 1: 16-bit pwm selected. bit6: ecomn: comparator function enable. this bit enables/disables the comp arator function for pca module n. 0: disabled. 1: enabled. bit5: cappn: capture positi ve function enable. this bit enables/disables the positive edge capture for pca module n. 0: disabled. 1: enabled. bit4: capnn: capture negative function enable. this bit enables/disables the negative edge capture for pca module n. 0: disabled. 1: enabled. bit3: matn: match function enable. this bit enables/disables the match function for pca module n. when enabled, matches of the pca counter with a module's capture/comp are register cause the ccfn bit in pca0md register to be set to logic 1. 0: disabled. 1: enabled. bit2: togn: toggle function enable. this bit enables/disables the toggle function for pca module n. when enabled, matches of the pca counter with a module's capture/comp are register cause the logic level on the cexn pin to toggle. if the pwmn bit is also set to logic 1, the module operates in frequency output mode. 0: disabled. 1: enabled. bit1: pwmn: pulse width modulation mode enable. this bit enables/disables the pwm function for pca module n. when enabled, a pulse width modulated signal is output on the cexn pin. 8-bi t pwm is used if pwm16n is cleared; 16-bit mode is used if pwm16n is set to logic 1. if the togn bit is also set, the module operates in frequency output mode. 0: disabled. 1: enabled. bit0: eccfn: capture/compare flag interrupt enable. this bit sets the masking of the capture/compare flag (ccfn) interrupt. 0: disable ccfn interrupts. 1: enable a capture/compare flag interrupt request when ccfn is set. r/w r/w r/w r/w r/w r/w r/w r/w reset value pwm16n ecomn cappn capnn matn togn pwmn eccfn 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: pca0cpm0: 0xda, pca0cpm1: 0xdb, pca0cpm2: 0xdc
c8051f330/1/2/3/4/5 210 rev. 1.5 sfr definition 19.4. pca0l: pca counter/timer low byte sfr definition 19.5. pca0h: pca counter /timer high byte sfr definition 19.6. pca0cpln: pca capture module low byte sfr definition 19.7. pca0cphn: pca captur e module high byte bits 7 ? 0: pca0l: pca counte r/timer low byte. the pca0l register holds the low byte (lsb) of the 16-bit pca counter/timer. r/w r/w r/w r/w r/w r/w r/w r/w reset value 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: 0xf9 bits 7 ? 0: pca0h: pca counter/timer high byte. the pca0h register holds the high byte (msb) of the 16-bit pca counter/timer. r/w r/w r/w r/w r/w r/w r/w r/w reset value 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: sfr address: 0xfa bits7 ? 0: pca0cpln: pca capture module low byte. the pca0cpln register holds the low byte (lsb) of the 16-bit capture module n. r/w r/w r/w r/w r/w r/w r/w r/w reset value 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: pca0cpl0: 0xfb, pca0cpl1: 0xe9, pca0cpl2: 0xeb bits7 ? 0: pca0cphn: pca capture module high byte. the pca0cphn register holds the high byte (msb) of the 16-bit capture module n. r/w r/w r/w r/w r/w r/w r/w r/w reset value 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sfr address: pca0cph0: 0xfc, pc a0cph1: 0xe9, pca0cph2: 0xec
rev. 1.5 211 c8051f330/1/2/3/4/5 20. c2 interface c8051f330/1/2/3/4/5 devices include an on-chip silicon labs 2-wire (c2) debug interf ace to allow flash programming and in-system debugging with the producti on part installed in the end application. the c2 interface uses a clock sig nal (c2ck) and a bi-directional c2 data signal (c2d) to transfer information between the device and a hos t system. see the c2 interface specificat ion for details on the c2 protocol. 20.1. c2 interface registers the following describes the c2 registers necessary to perform flash programming through the c2 inter - face. all c2 registers are accessed through the c2 inte rface as described in the c2 interface specification. c2 register definition 20.1. c2add: c2 address c2 register definition 20.2. deviceid: c2 device id bits7?0: the c2add register is accessed via the c2 interface to select the ta rget data register for c2 data read and data write commands. reset value 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 address description 0x00 selects the device id regi ster for data read instructions 0x01 selects the revision id regi ster for data read instructions 0x02 selects the c2 flash programming control register for data read/write instructions 0xb4 selects the c2 flash programming data register for data read/write instructions this read-only register returns the 8-bit device id: 0x0a (c8051f330/1/2/3/4/5). reset value 00001010 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0
c8051f330/1/2/3/4/5 212 rev. 1.5 c2 register definition 20.3. revid: c2 revision id c2 register definition 20.4. fpctl: c2 flash programming control c2 register definition 20.5. fpdat: c2 flash programming data this read-only register returns the 8-bit revision id: 0x00 (revision a). reset value 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 bits7 ? 0 fpctl: flash programming control register. this register is used to enable flash programmi ng via the c2 interface. to enable c2 flash programming, the following codes must be writte n in order: 0x02, 0x01. note that once c2 flash programming is enabled, a system reset mu st be issued to resume normal operation. reset value 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 bits7 ? 0: fpdat: c2 flash programming data register. this register is used to pass flash comma nds, addresses, and data during c2 flash accesses. valid commands are listed below. reset value 00000000 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 code command 0x06 flash block read 0x07 flash block write 0x08 flash page erase 0x03 device erase
rev. 1.5 213 c8051f330/1/2/3/4/5 20.2. c2 pin sharing the c2 protocol allows the c2 pins to be shared wi th user functions so that in-system debugging and flash programming may be performed. this is possible because c2 communication is typically performed when the device is in the halt state, where all on-chip peripherals and user software are stalled. in this halted state, the c2 interface can safely ?borrow? the c2ck ( rst ) and c2d (p2.0) pins. in most applica - tions, external resistors are required to isolate c2 inte rface traffic from the user application. a typical isola - tion configuration is shown in figure 20.1 . figure 20.1. typical c2 pin sharing the configuration in figure 20.1 assumes the following: 1. the user input (b) cannot change stat e while the target device is halted. 2. the rst pin on the target device is used as an input only. additional resistors may be necessary depending on the specific application. c2d c2ck /reset (a) input (b) output (c) c2 interface master c8051fxxx
c8051f330/1/2/3/4/5 214 rev. 1.5 d ocument c hange l ist revision 1.4 to revision 1.5 ? updated ta b l e 3.1 - added supply current data from characterization. ? updated ta b l e 5.1 - added min/max numbers for a dc offset and full scale error. ?fixed sfr definition 8.2 - typo in bit descriptions - ?2-0? changed to ?3-0?. ?fixed sfr definition 9.4 - text at bottom of figure was cut off. ? added section ?11.4. flash write and erase guidelines? on page 109 . ?fixed section ?12. external ram? on page 113 , paragraph 2 - typo in description - ?upper 6-bits? changed to ?upper 7 bits?. ? fixed text in section ?19.3.2. watchdog timer usage? on page 205 to read ?256 pca clock cycles, or 3072 system clock cycles?. ? changed table 19.4 , note 2 to refer to sysclk reset frequency = internal oscillator / 8. ?fixed equation 19.6, ?watchdog timer offset in pca clocks,? - typo in equation - ?pca0cpl4? changed to ?pca0cpl2?. revision 1.3 to revision 1.4 ? removed references to c8051f330d throughout the data sheet because the 'f330d device is func - tionally identical to the c8051f330 device (these two part numbers differ by package type only). ? updated titles of chapters 5, 6, and 7 to show supported devices. ? updated ta b l e 1.1, ?product selection guide,? on page 18 . - added ordering part number information for lead-free parts. ? added ta b l e 3.2, ?index to electrical ch aracteristics tables,? on page 34 ? added ta b l e 11.2, ?flash security summary,? on page 108 for clarity, replacing the flash security sum - maries text.
rev. 1.5 215 c8051f330/1/2/3/4/5 n otes :
c8051f330/1/2/3/4/5 216 rev. 1.5 c ontact i nformation silicon laboratories inc. 4635 boston lane austin, tx 78735 tel: 1+(512) 416-8500 fax: 1+(512) 416-9669 toll free: 1+(877) 444-3032 email: mcuinfo@silabs.com internet: www.silabs.com silicon laboratories and silicon labs are trademarks of silicon laboratories inc. other products or brandnames mentioned herein are trademark s or registered trademarks of their respective holders the information in this document is believed to be accurate in al l respects at the time of publ ication but is subject to change without notice. silicon laboratories assumes no re sponsibility for errors and omissions, and disclaims responsibi lity for any consequen ces resulting from the use of information included herein. additi onally, silicon laborator ies assumes no responsibility for the fun ction- ing of undescribed features or parameters. silicon laboratories re serves the right to make change s without further notice. sili con laboratories makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpos e, nor does silicon laboratories assume any liabi lity arising out of the application or use of any product or circuit, and specifi cally disclaims any and all liability, including without limitation consequential or incident al damages. silicon laboratories product s are not designed, intended, or authorized for use in applications in tended to support or sustain life, or for any other application in which the failure of the silicon laboratories product could create a si tuation where personal injury or death may occur. should buyer purchase or use silicon laboratories prod ucts for any such unintended or unauthorized application, buyer shall indemnify and hold silicon laboratories harmless against all claims and damages.

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