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1 0401g?micro?3/06 features compatible with mcs ? 51 products 8k bytes of in-system reprogra mmable downloadable flash memory ? spi serial interface for program downloading ? endurance: 1,000 write/erase cycles 2k bytes eeprom ? endurance: 100,000 write/erase cycles 4v to 6v operating range fully static operation: 0 hz to 24 mhz three-level program memory lock 256 x 8-bit internal ram 32 programmable i/o lines three 16-bit timer/counters nine interrupt sources programmable uart serial channel spi serial interface low-power idle and power-down modes interrupt recovery from power-down programmable watchdog timer dual data pointer power-off flag description the AT89S8252 is a low-power, high-performance cmos 8-bit microcontroller with 8k bytes of downloadable flash programmable and erasable read-only memory and 2k bytes of eeprom. the device is manufactured using atmel?s high-density nonvolatile memory technology and is compatible wit h the industry-standard 80c51 instruction set and pinout. the on-chip downloadable flash allows the program memory to be reprogrammed in-system through an spi serial interface or by a conventional nonvol- atile memory programmer. by combining a versatile 8-bit cpu with downloadable flash on a monolithic chip, the atmel at89s8 252 is a powerful microcontroller, which provides a highly-flexible and cost-effective solution to many embedded control applications. the AT89S8252 provides the following standard features: 8k bytes of downloadable flash, 2k bytes of eeprom, 256 bytes of ram, 32 i/o lines, programmable watchdog timer, two data pointers, three 16-bit timer/counters, a six-vector two-level interrupt architecture, a full duplex serial port, on-chip oscillator, and clock circuitry. in addition, the AT89S8252 is designed with static logic for operation down to zero frequency and supports two software selectable power saving modes. the idle mode stops the cpu while allowing the ram, timer/counters, serial port, and interrupt system to continue functioning. the power-down mode saves t he ram contents but freezes the oscillator, disabling all other chip functions until the next external interrupt or hardware reset. the downloadable flash can be changed a single byte at a time and is accessible through the spi serial interface. holding reset active fo rces the spi bus into a serial programming interface and allows the program memory to be written to or read from unless lock bits have been activated. 8-bit microcontroller with 8k bytes flash AT89S8252 not recommended for new designs. use at89s8253.
2 AT89S8252 0401g?micro?3/06 pin configurations pdip 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 (t2) p1.0 (t2 ex) p1.1 p1.2 p1.3 (ss) p1.4 (mosi) p1.5 (miso) p1.6 (sck) p1.7 rst (rxd) p3.0 (txd) p3.1 (int0) p3.2 (int1) p3.3 (t0) p3.4 (t1) p3.5 (wr) p3.6 (rd) p3.7 xtal2 xtal1 gnd vcc p0.0 (ad0) p0.1 (ad1) p0.2 (ad2) p0.3 (ad3) p0.4 (ad4) p0.5 (ad5) p0.6 (ad6) p0.7 (ad7) ea/vpp ale/prog psen p2.7 (a15) p2.6 (a14) p2.5 (a13) p2.4 (a12) p2.3 (a11) p2.2 (a10) p2.1 (a9) p2.0 (a8) tqfp 1 2 3 4 5 6 7 8 9 10 11 33 32 31 30 29 28 27 26 25 24 23 44 43 42 41 40 39 38 37 36 35 34 12 13 14 15 16 17 18 19 20 21 22 (mosi) p1.5 (miso) p1.6 (sck) p1.7 rst (rxd) p3.0 nc (txd) p3.1 (int0) p3.2 (int1) p3.3 (t0) p3.4 (t1) p3.5 p0.4 (ad4) p0.5 (ad5) p0.6 (ad6) p0.7 (ad7) ea/vpp nc ale/prog psen p2.7 (a15) p2.6 (a14) p2.5 (a13) p1.4 (ss) p1.3 p1.2 p1.1 (t2 ex) p1.0 (t2) nc vcc p0.0 (ad0) p0.1 (ad1) p0.2 (ad2) p0.3 (ad3) (wr) p3.6 (rd) p3.7 xtal2 xtal1 gnd gnd (a8) p2.0 (a9) p2.1 (a10) p2.2 (a11) p2.3 (a12) p2.4 plcc pin description vcc supply voltage. gnd ground. port 0 port 0 is an 8-bit open drain bi-didirectional i/o port. as an output port, each pin can sink eight ttl inputs. when 1s are written to port 0 pins, the pins can be used as high- impedance inputs. port 0 can also be configured to be the multiplexed low-order address/data bus during accesses to external program and data memory. in this mode, p0 has internal pull-ups. port 0 also receives the code bytes duri ng flash programming and outputs the code bytes during program verification. external pull-ups are required during program verification. port 1 port 1 is an 8-bit bi-directional i/o port with internal pull-ups. the port 1 output buffers can sink/source four ttl inputs. when 1s are written to port 1 pins, they are pulled high by the internal pull-ups and can be used as i nputs. as inputs, port 1 pins that are exter- nally being pulled low will source current (i il ) because of the internal pull-ups. 7 8 9 10 11 12 13 14 15 16 17 39 38 37 36 35 34 33 32 31 30 29 (mosi) p1.5 (miso) p1.6 (sck) p1.7 rst (rxd) p3.0 nc (txd) p3.1 (int0) p3.2 (int1) p3.3 (t0) p3.4 (t1) p3.5 p0.4 (ad4) p0.5 (ad5) p0.6 (ad6) p0.7 (ad7) ea/vpp nc ale/prog psen p2.7 (a15) p2.6 (a14) p2.5 (a13) 6 5 4 3 2 1 44 43 42 41 40 18 19 20 21 22 23 24 25 26 27 28 (wr) p3.6 (rd) p3.7 xtal2 xtal1 gnd nc (a8) p2.0 (a9) p2.1 (a10) p2.2 (a11) p2.3 (a12) p2.4 p1.4 (ss) p1.3 p1.2 p1.1 (t2 ex) p1.0 (t2) nc vcc p0.0 (ad0) p0.1 (ad1) p0.2 (ad2) p0.3 (ad3)
3 AT89S8252 0401g?micro?3/06 block diagram port 2 drivers port 2 latch p2.0 - p2.7 flash port 0 latch ram eeprom program address register buffer pc incrementer program counter dual dptr instruction register b register interrupt, serial port, and timer blocks stack pointer acc tmp2 tmp1 alu psw timing and control port 1 drivers p1.0 - p1.7 port 3 latch port 3 drivers p3.0 - p3.7 osc gnd v cc psen ale/prog ea / v pp rst ram addr. register port 0 drivers p0.0 - p0.7 port 1 latch watch dog spi port program logic
4 AT89S8252 0401g?micro?3/06 some port 1 pins provide additional functi ons. p1.0 and p1.1 can be configured to be the timer/counter 2 external count input (p1.0/t2) and the timer/counter 2 trigger input (p1.1/t2ex), respectively. furthermore, p1.4, p1.5, p1.6, and p1.7 can be configured as the spi slave port select, data input/output and shift clock input/output pins as shown in the following table. port 1 also receives the low-order address bytes during flash programming and verification. port 2 port 2 is an 8-bit bi-directional i/o port with internal pull-ups. the port 2 output buffers can sink/source four ttl inputs. when 1s are written to port 2 pins, they are pulled high by the internal pull-ups and can be used as in puts. as inputs, port 2 pins that are exter- nally being pulled low will source current (i il ) because of the internal pull-ups. port 2 emits the high-order address byte during fetches from external program memory and during accesses to external data memory that use 16-bit addresses (movx @ dptr). in this application, port 2 uses st rong internal pull-ups when emitting 1s. during accesses to external data memory that use 8-bit addresses (movx @ ri), port 2 emits the contents of the p2 special function register. port 2 also receives the high-order address bits and some control signals during flash programming and verification. port 3 port 3 is an 8-bit bi-directional i/o port with internal pull-ups. the port 3 output buffers can sink/source four ttl inputs. when 1s are written to port 3 pins, they are pulled high by the internal pull-ups and can be used as in puts. as inputs, port 3 pins that are exter- nally being pulled low will source current (i il ) because of the pull-ups. port 3 receives some control signals for flash programming and verification. port 3 also serves the functions of various special features of the AT89S8252, as shown in the following table. port pin alternate functions p1.0 t2 (external count input to timer/counter 2), clock-out p1.1 t2ex (timer/counter 2 capture/reload trigger and direction control) p1.4 ss (slave port select input) p1.5 mosi (master data output, slave data input pin for spi channel) p1.6 miso (master data input, slav e data output pin for spi channel) p1.7 sck (master clock output, slave clock input pin for spi channel)
5 AT89S8252 0401g?micro?3/06 rst reset input. a high on this pin for two machine cycles while the oscillator is running resets the device. ale/ prog address latch enable is an output pulse for latching the low byte of the address during accesses to external memory. this pin is also the program pulse input (prog ) during flash programming. in normal operation, ale is emitted at a constant rate of 1/6 the oscillator frequency and may be used for external timing or clocking purposes. note, however, that one ale pulse is skipped during each access to external data memory. if desired, ale operation can be disabled by setting bit 0 of sfr location 8eh. with the bit set, ale is active only during a movx or movc instruction. otherwise, the pin is weakly pulled high. setting the ale-disable bit has no effect if the microcontroller is in external execution mode. psen program store enable is the read strobe to external program memory. when the AT89S8252 is executing code fr om external program memory, psen is acti- vated twice each machine cycle, except that two psen activations are skipped during each access to external data memory. ea /vpp external access enable. ea must be strapped to gnd in order to enable the device to fetch code from external program memory locations starting at 0000h up to ffffh. note, however, that if lock bit 1 is programmed, ea will be internally latched on reset. ea should be strapped to v cc for internal program executions. this pin also receives the 12-volt programming enable voltage (v pp ) during flash programming when 12-volt pro- gramming is selected. xtal1 input to the inverting oscillator amplifier and input to the inte rnal clock operating circuit. xtal2 output from the invert ing oscillator amplifier. port pin alternate functions p3.0 rxd (serial input port) p3.1 txd (serial output port) p3.2 int0 (external interrupt 0) p3.3 int1 (external interrupt 1) p3.4 t0 (timer 0 external input) p3.5 t1 (timer 1 external input) p3.6 wr (external data memory write strobe) p3.7 rd (external data memory read strobe)
6 AT89S8252 0401g?micro?3/06 special function registers a map of the on-chip memory area called the special function register (sfr) space is shown in table 1. note that not all of the addresses are occupied, and unoccupied addresses may not be implemented on the chip. read accesses to thes e addresses will in general return ran- dom data, and write accesses will have an indeterm inate effect. user software should not write 1s to these unlisted locations, since they may be used in future products to invoke new features. in that case, the reset or inactive values of the new bits will always be 0. timer 2 registers control and status bits are contained in registers t2con (shown in table 2) and t2mod (shown in table 9) for timer 2. the register pair (rcap2h, rcap2l) are the capture/reload registers for timer 2 in 16-bit capture mode or 16-bit auto-reload mode. table 1. AT89S8252 sfr map and reset values 0f8h 0ffh 0f0h b 00000000 0f7h 0e8h 0efh 0e0h acc 00000000 0e7h 0d8h 0df h 0d0h psw 00000000 spcr 000001xx 0d7h 0c8h t2con 00000000 t2mod xxxxxx00 rcap2l 00000000 rcap2h 00000000 tl2 00000000 th2 00000000 0cf h 0c0h 0c7h 0b8h ip xx000000 0bfh 0b0h p3 11111111 0b7h 0a8h ie 0x000000 spsr 00xxxxxx 0afh 0a0h p2 11111111 0a7h 98h scon 00000000 sbuf xxxxxxxx 9fh 90h p1 11111111 wmcon 00000010 97h 88h tcon 00000000 tmod 00000000 tl0 00000000 tl1 00000000 th0 00000000 th1 00000000 8fh 80h p0 11111111 sp 00000111 dp0l 00000000 dp0h 00000000 dp1l 00000000 dp1h 00000000 spdr xxxxxxxx pcon 0xxx0000 87h
7 AT89S8252 0401g?micro?3/06 table 2. t2con ? timer/counter 2 control register t2con address = 0c8h reset value = 0000 0000b bit addressable tf2 exf2 rclk tclk exen2 tr2 c/t2 cp/rl2 bit76543210 symbol function tf2 timer 2 overflow flag set by a timer 2 overflow and must be cleared by software. tf2 will not be set when either rclk = 1 or tclk = 1. exf2 timer 2 external flag set when either a capture or reload is caused by a negative transition on t2ex and exen2 = 1. when timer 2 interrupt is enabled, exf2 = 1 will cause the cpu to vector to the timer 2 interrupt routine. exf2 must be cleared by software. exf2 does not cause an interrupt in up/down counter mode (dcen = 1). rclk receive clock enable. when set, causes the serial port to use timer 2 overflow pulses for its receive clock in serial port modes 1 and 3. rclk = 0 causes timer 1 overflows to be used for the receive clock. tclk transmit clock enable. when set, causes the serial port to use timer 2 overflow pulses for its transmit clock in serial por t modes 1 and 3. tclk = 0 causes timer 1 overflows to be used for the transmit clock. exen2 timer 2 external enable. when set, allows a capture or reload to occur as a result of a negative transition on t2ex if timer 2 is not being used to clock the serial port. exen2 = 0 causes timer 2 to ignore events at t2ex. tr2 start/stop control for timer 2. tr2 = 1 starts the timer. c/t2 timer or counter select for timer 2. c/t2 = 0 for timer function. c/t2 = 1 for external event counter (falling edge triggered). cp/rl2 capture/reload select. cp/rl2 = 1 causes captures to occur on negativ e transitions at t2ex if exen2 = 1. cp/rl2 = 0 causes automatic reloads to oc cur when timer 2 overflows or negative transitions occur at t2ex when exen2 = 1. when either rclk or tclk = 1, this bit is ignored and t he timer is forced to auto-reload on timer 2 overflow.
8 AT89S8252 0401g?micro?3/06 watchdog and memory control register the wmcon register contains control bits for the watchdog timer (shown in table 3). the eemen and eemwe bits are used to select t he 2k bytes on-chip eeprom, and to enable byte-write. the dps bit selects one of two dptr registers available. table 3. wmcon?watchdog and memory control register wmcon address = 96h reset value = 0000 0010b ps2 ps1 ps0 eemwe eemen dps wdtrst wdten bit76543210 symbol function ps2 ps1 ps0 prescaler bits for the watchdog timer. when all three bits are set to ?0?, the watchdog timer has a nominal period of 16 ms. when all three bits are set to ?1?, the nominal period is 2048 ms. eemwe eeprom data memory write enable bit. set this bit to ?1? before initiating byte wr ite to on-chip eeprom with the movx instruction. user software should set this bit to ?0? af ter eeprom write is completed. eemen internal eeprom access enable. when eemen = 1, the movx instruction with dptr will access on-chip eeprom instead of external data memory. when eemen = 0, movx with dptr accesses external data memory. dps data pointer register select. dps = 0 selects the first bank of data pointer register, dp0, and dps = 1 selects the second bank, dp1 wdtrst rdy/bsy watchdog timer reset and eeprom ready/busy flag. each time this bit is set to ?1? by user software, a pulse is generated to reset the watchdog timer. the wdtrst bit is then automatically reset to ?0? in the next instruction cycle. the wdtrst bit is write-only. this bit also serves as the rdy/bsy flag in a read-only mode during eeprom write. rdy/bsy = 1 means that the eeprom is read y to be programmed. while programming operations are being executed, the rdy/bsy bit equals ?0? and is automatically reset to ?1? when programming is completed. wdten watchdog timer enable bit. wdten = 1 enables the watchdog timer and wdten = 0 disables the watchdog timer.
9 AT89S8252 0401g?micro?3/06 spi registers control and status bits for the serial peripheral interface are contained in registers spcr (shown in table 4) and spsr (shown in table 5). the spi data bits are contained in the spdr register. writing the spi data register during serial data transfer sets the write collision bit, wcol, in the spsr register . the spdr is double buffered for writing and the values in spdr are not changed by reset. interrupt registers the global interrupt enable bit and the individual interrupt enable bits are in the ie register. in addition, the individual interrupt enable bit for the spi is in the spcr register. two priorities can be set for each of the six interrupt sources in the ip register. dual data pointer registers to facilitate accessing both internal eeprom and exter- nal data memory, two banks of 16-bit data pointer registers are provided: dp0 at sfr address locations 82h-83h and dp1 at 84h- 85h. bit dps = 0 in sfr wmcon selects dp0 and dps = 1 selects dp1. the user should always initialize the dps bit to the appropriate value before accessing the respective data pointer register. power off flag the power off flag (pof) is located at bit_4 (pcon.4) in the pcon sfr. pof is set to ?1? during power up. it can be set and reset under software control and is not affected by reset. table 4. spcr ? spi control register spcr address = d5h reset value = 0000 01xxb spie spe dord mstr cpol cpha spr1 spr0 bit76543210 symbol function spie spi interrupt enable. this bit, in conjunction with the es bi t in the ie register, enables spi interrupts: spie = 1 and es = 1 enable spi interrupts. spie = 0 disables spi interrupts. spe spi enable. spi = 1 enables the spi channel and connects ss , mosi, miso and sck to pins p1.4, p1.5, p1.6, and p1.7. spi = 0 disables the spi channel. dord data order. dord = 1 selects lsb first data transm ission. dord = 0 selects msb first data transmission. mstr master/slave select. mstr = 1 selects mast er spi mode. mstr = 0 selects slave spi mode. cpol clock polarity. when cpol = 1, sck is high when idle. wh en cpol = 0, sck of the master device is low when not transmitting. please refer to figure on spi clock phase and polarity control. cpha clock phase. the cpha bit together with the cpol bit c ontrols the clock and data relationship between master and slave. please refer to figure on spi clock phase and polarity control. spr0 spr1 spi clock rate select. these two bits control the sck rate of the device configured as master. spr1 and spr0 have no effect on the slave. the relationship between sck and the oscillator frequency, f osc. , is as follows: spr1 spr0 sck = f osc. divided by 00 4 0116 1064 11128
10 AT89S8252 0401g?micro?3/06 data memory ? eeprom and ram the AT89S8252 implements 2k bytes of on-chip eeprom for data storage and 256 bytes of ram. the upper 128 bytes of ram occupy a parallel space to the special function registers. that means the upper 128 bytes have the same addresses as the sfr space but are physically separate from sfr space. when an instruction accesses an internal location above address 7fh, the address mode used in the instruction specifies whether the cpu accesses the upper 128 bytes of ram or the sfr space. instructions that use direct addressing access sfr space. for example, the following direct addressing instruction accesses the sfr at location 0a0h (which is p2). mov 0a0h, #data instructions that use indirect addressing access the upper 128 bytes of ram. for exam- ple, the following indirect addressing instruction, where r0 contains 0a0h, accesses the data byte at address 0a0h, rather than p2 (whose address is 0a0h). mov @r0, #data note that stack operations are examples of indirect addressing, so the upper 128 bytes of data ram are available as stack space. the on-chip eeprom data memory is se lected by setting the eemen bit in the wmcon register at sfr addr ess location 96h. the eeprom address rang e is from 000h to 7ffh. the movx instructions ar e used to access the eeprom. to access off- chip data memory with the movx instructions, the eemen bit needs to be set to ?0?. the eemwe bit in the wmcon register needs to be set to ?1? before any byte location in the eeprom can be written. user software should reset eemwe bit to ?0? if no fur- ther eeprom write is requir ed. eeprom write cycles in t he serial progr amming mode are self-timed and ty pically take 2.5 ms. the progre ss of eeprom write can be moni- tored by reading the rdy/bsy bit (read-only) in sfr wmcon. rdy/bsy = 0 means table 5. spsr ? spi status register spsr address = aah reset value = 00xx xxxxb spifwcol?????? bit76543210 symbol function spif spi interrupt flag. when a serial transfer is complete, the spif bit is set and an interrupt is generated if spie = 1 and e s = 1. the spif bit is cleared by reading th e spi status register with spif and wcol bits set, and then reading/writing the spi data register. wcol write collision flag. the wcol bit is set if the spi data r egister is written during a data transfer. during data transfer, the result of reading the spdr regist er may be incorrect, and writing to it has no effect. the wcol bit (and the spif bit) are cleared by reading the spi status r egister with spif and wcol set, and then accessing the spi data register. table 6. spdr ? spi data register spdr address = 86h reset value = unchanged spd7 spd6 spd5 spd4 spd3 spd2 spd1 spd0 bit76543210
11 AT89S8252 0401g?micro?3/06 programming is still in progress and rdy/bsy = 1 means eeprom write cycle is com- pleted and another write cycle can be initiated. in addition, during eeprom programming, an attempted read from the eeprom will fetch the byte being written with the msb complemented. once the write cycle is com- pleted, true data are valid at all bit locations. programmable watchdog timer the programmable watchdog timer (wdt) operates from an independent internal oscillator. the prescaler bits, ps0, ps1 and ps2 in sfr wmcon are used to set the period of the watchdog timer from 16 ms to 2048 ms. the available timer periods are shown in the following table and the actual timer periods (at v cc = 5v) are within 30% of the nominal. the wdt is disabled by power-on reset and during power-down. it is enabled by set- ting the wdten bit in sfr wmcon (address = 96h). the wdt is reset by setting the wdtrst bit in wmcon. when the wdt time s out without being reset or disabled, an internal rst pulse is generated to reset the cpu. timer 0 and 1 timer 0 and timer 1 in the AT89S8252 operate the same way as timer 0 and timer 1 in the at89c51 and at89c52. for further information on the timers? operation, refer to the atmel web site (http://www.atmel.com). from the home page, select ?products?, then ?microcontrollers, then ?8051-architecture?. click on ?d ocumentation?, th en on ?other documents?. open the document ?at89 series hardware description?. timer 2 timer 2 is a 16-bit timer/counter that can operate as either a timer or an event counter. the type of operation is selected by bit c/t2 in the sfr t2con (shown in table 2). timer 2 has three operating modes: capture, auto-reload (up or down counting), and baud rate generator. the modes are selected by bits in t2con, as shown in table 8. timer 2 consists of two 8-bit registers, th2 and tl2. in the timer function, the tl2 reg- ister is incremented every machine cycle. since a machine cycle consists of 12 oscillator periods, the count rate is 1/12 of the oscillator frequency. in the counter function, the register is incremented in response to a 1-to-0 transition at its corresponding external input pin, t2. in this function, the external input is sampled during s5p2 of every machine cycle. when the samples show a high in one cycle and a low in the next cycle, the count is incremented. the new count value appears in the reg- ister during s3p1 of the cycle following t he one in which the transition was detected. table 7. watchdog timer period selection wdt prescaler bits period (nominal) ps2 ps1 ps0 0 0 0 16 ms 0 0 1 32 ms 0 1 0 64 ms 0 1 1 128 ms 1 0 0 256 ms 1 0 1 512 ms 1 1 0 1024 ms 1 1 1 2048 ms
12 AT89S8252 0401g?micro?3/06 since two machine cycles (24 oscillator periods ) are required to reco gnize a 1-to-0 tran- sition, the maximum count rate is 1/24 of th e oscillator frequency. to ensure that a given level is sampled at leas t once before it changes, the level should be held for at least one full machine cycle. capture mode in the capture mode, two opti ons are selected by bit exen2 in t2con. if exen2 = 0, timer 2 is a 16-bit timer or counter which upon overflow sets bit tf2 in t2con. this bit can then be used to generate an interrupt. if exen2 = 1, timer 2 performs the same operation, but a l-to-0 transition at external input t2ex also causes the current value in th2 and tl2 to be captured into rcap2h and rcap2l, respectively. in addition, the transition at t2ex causes bit exf2 in t2con to be set. the exf2 bit, like tf2, can generate an inte rrupt. the capture mode is illustrated in figure 1. figure 1. timer 2 in capture mode table 8. timer 2 operating modes rclk + tclk cp/rl2 tr2 mode 0 0 1 16-bit auto-reload 0 1 1 16-bit capture 1 x 1 baud rate generator x x 0 (off) osc exf2 t2ex pin t2 pin tr2 exen2 c/t2 = 0 c/t2 = 1 control capture overflow control transition detector timer 2 interrupt 12 rcap2l rcap2h th2 tl2 tf2
13 AT89S8252 0401g?micro?3/06 auto-reload (up or down counter) timer 2 can be programmed to count up or down when configured in its 16-bit auto- reload mode. this feature is invoked by the dcen (down counter enable) bit located in the sfr t2mod (see table 9). upon reset, t he dcen bit is set to 0 so that timer 2 will default to count up. when dcen is set, timer 2 can count up or down, depending on the value of the t2ex pin. figure 2 shows timer 2 automatically counti ng up when dcen = 0. in this mode, two options are selected by bit exen2 in t2con. if exen2 = 0, timer 2 counts up to 0ffffh and then sets the tf2 bit upon overflow. the overflow also causes the timer registers to be reloaded with the 16-bit value in rcap2h and rcap2l. the values in rcap2h and rcap2l are preset by software. if exen2 = 1, a 16-bit reload can be trig- gered either by an overflow or by a 1-to-0 transition at external input t2ex. this transition also sets the exf2 bit. both the tf2 and exf2 bits can generate an interrupt if enabled. setting the dcen bit enables timer 2 to count up or down, as shown in figure 3. in this mode, the t2ex pin controls the direction of the count. a logic 1 at t2ex makes timer 2 count up. the timer will overflow at 0ffffh and set the tf2 bit. this overflow also causes the 16-bit value in rcap2h and rcap2l to be reloaded into the timer registers, th2 and tl2, respectively. a logic 0 at t2ex makes timer 2 count down. the timer underflows when th2 and tl2 equal the values stored in rcap2h and rcap2l. the underflow sets the tf2 bit and causes 0ffffh to be reloaded into the timer registers. the exf2 bit toggles whenever timer 2 overfl ows or underflows and can be used as a 17th bit of resolution. in this operating mode, exf2 does not flag an interrupt. figure 2. timer 2 in auto reload mode (dcen = 0)
14 AT89S8252 0401g?micro?3/06 figure 3. timer 2 auto reload mode (dcen = 1) table 9. t2mod ? timer 2 mode control register t2mod address = 0c9h reset value = xxxx xx00b not bit addressable ??????t2oedcen bit76543210 symbol function ? not implemented, reserved for future use. t2oe timer 2 output enable bit. dcen when set, this bit allows timer 2 to be configured as an up/down counter.
15 AT89S8252 0401g?micro?3/06 figure 4. timer 2 in baud rate generator mode baud rate generator timer 2 is selected as the baud rate generator by setting tclk and/or rclk in t2con (table 2). note that the baud rates for transmit and receive can be different if timer 2 is used for the receiver or transmitter and timer 1 is used for the other function. setting rclk and/or tclk puts timer 2 into its baud rate generator mode, as shown in figure 4. the baud rate generator mode is similar to the auto-reload mode, in that a rollover in th2 causes the timer 2 registers to be re loaded with the 16-bit value in registers rcap2h and rcap2l, which are preset by software. the baud rates in modes 1 and 3 are determined by timer 2?s overflow rate according to the following equation. the timer can be configured for either timer or counter operation. in most applications, it is configured for timer operation (cp/t2 = 0). the timer operation is different for timer 2 when it is used as a baud rate generator. normally, as a timer, it increments every machine cycle (at 1/12 the osc illator frequency). as a baud ra te generator, however, it increments every state time (at 1/2 the oscillator frequency). the baud rate formula is given below. where (rcap2h, rcap2l) is the content of rcap2h and rcap2l taken as a 16-bit unsigned integer. osc smod1 rclk tclk rx clock tx clock t2ex pin t2 pin tr2 control "1" "1" "1" "0" "0" "0" timer 1 overflow note: osc. freq. is divided by 2, not 12 timer 2 interrupt 2 2 16 16 rcap2l rcap2h th2 tl2 c/t2 = 0 c/t2 = 1 exf2 control transition detector exen2 modes 1 and 3 baud rates timer 2 overflow rate 16 ----------------------------------------------------------- - = modes 1 and 3 baud rate --------------------------------------- oscillator frequency 32 65536 rcap2h,rcap2l () ? [] ---------------------------------------------------------------------------------------------- =
16 AT89S8252 0401g?micro?3/06 timer 2 as a baud rate generator is shown in figure 4. this figure is valid only if rclk or tclk = 1 in t2con. note that a rollove r in th2 does not set tf2 and will not gener- ate an interrupt. note too, t hat if exen2 is set, a 1-to-0 transition in t2ex will set exf2 but will not cause a reload from (rcap2h, rcap2l) to (th2 , tl2). thus when timer 2 is in use as a baud rate generator, t2ex c an be used as an extra external interrupt. note that when timer 2 is running (tr2 = 1) as a timer in the baud rate generator mode, th2 or tl2 should not be read from or written to. under these conditions, the timer is incremented every state time, and the results of a read or write may not be accurate. the rcap2 registers may be read but should not be written to, because a write might overlap a reload and cause write and/or reload errors. the timer should be turned off (clear tr2) before accessing the timer 2 or rcap2 registers. programmable clock out a 50% duty cycle clock can be programmed to come out on p1.0, as shown in figure 5. this pin, besides being a regular i/0 pin, has two alternate functions. it can be pro- grammed to input the external clock for ti mer/counter 2 or to output a 50% duty cycle clock ranging from 61 hz to 4 mhz (for a 16 - mhz operating frequency). to configure the timer/counter 2 as a clock generator, bit c/t2 (t2con.1) must be cleared and bit t2oe (t2mod.1) must be set. bit tr2 (t2con.2) starts and stops the timer. the clock-out frequency depends on the osci llator frequency and the reload value of timer 2 capture registers (rcap2h, rcap2l), as shown in the following equation. in the clock-out mode, timer 2 rollovers will not generate an interrupt. this behavior is similar to when timer 2 is used as a baud-rate generator. it is possible to use timer 2 as a baud-rate generator and a clock generator simultaneously. note, however, that the baud-rate and clock-out frequencies cannot be determined independently from one another since they both use rcap2h and rcap2l. clock out frequency oscillator frequency 4 65536 rcap2h,rcap2l () ? [] ------------------------------------------------------------------------------------------ - =
17 AT89S8252 0401g?micro?3/06 figure 5. timer 2 in clock-out mode figure 6. spi block diagram oscillator 8/16-bit shift register read data buffer pin contr ol logic spi control spi status register spi interrupt request internal data b u s select spi clock (master) divider 41664128 spi control register 8 8 8 spif wcol spr1 mstr spie clock logic clock msb s m spe dord mstr cpol cpha spr1 spr0 mstr spe dord lsb s m m s miso p1.6 mosi p1.5 sck 1.7 ss p1.4 spr0 spe
18 AT89S8252 0401g?micro?3/06 uart the uart in the AT89S8252 operates the same way as the uart in the at89c51 and at89c52. for further information on the uart operation, refer to the atmel web site (http://www.atmel.com). from the home page, select ?products?, then ?microcontrollers, then ?8051-architecture?. click on ?documentation?, then on ?other documents?. open the document ?at89 series hardware description?. serial peripheral interface the serial peripheral interface (spi) allows high-speed synchronous data transfer between the AT89S8252 and peripheral devices or between several AT89S8252 devices. the AT89S8252 spi features include the following: full-duplex, 3-wire synchronous data transfer master or slave operation 1.5 mhz bit frequency (max.) lsb first or msb first data transfer four programmable bit rates end of transmission interrupt flag write collision flag protection wakeup from idle mode (slave mode only) the interconnection between master and slave cpus with spi is shown in the following figure. the sck pin is the clock output in the master mode but is the clock input in the slave mode. writing to the spi data register of the master cpu starts the spi clock gen- erator, and the data written shifts out of the mosi pin and into the mosi pin of the slave cpu. after shifting one byte, the spi clock generator stops, setting the end of transmis- sion flag (spif). if both the spi interrupt enable bit (spie) and the serial port interrupt enable bit (es) are set, an interrupt is requested. the slave select input, ss /p1.4, is set low to select an individual spi device as a slave. when ss /p1.4 is set high, the spi port is deactivated and the mosi/p1.5 pin can be used as an input. there are four combinations of sck phase and polarity with respect to serial data, which are determined by control bits cpha and cpol. the spi data transfer formats are shown in figure 8 and figure 9. figure 7. spi master-slave interconnection 8-bit shift register master clock generator spi miso 8-bit shift register slave miso mosi mosi sck sck ss ss v cc msb lsb msb lsb
19 AT89S8252 0401g?micro?3/06 figure 8. spi transfer format with cpha = 0 note: *not defined but normally msb of character just received figure 9. spi transfer form at with cpha = 1 note: *not defined but normally lsb of previously transmitted character. interrupts the AT89S8252 has a total of six interrupt vectors: two external interrupts (int0 and int1 ), three timer interrupts (timers 0, 1, and 2), and the serial port interrupt. these interrupts are all shown in figure 10. each of these interrupt sources can be individually enabled or disabled by setting or clearing a bit in special function register ie . ie also contains a global disable bit, ea, which disables all interrupts at once. note that table 10 shows that bit position ie .6 is unimplemented. in the at89c51, bit position ie.5 is also unimplemented. user so ftware should not write 1s to these bit posi- tions, since they may be used in future at89 products. timer 2 interrupt is generated by the logical or of bits tf2 and exf2 in register t2con. neither of these flags is cleared by hardware when the service routine is vec- tored to. in fact, the service routine may have to determine whether it was tf2 or exf2 that generated the interrup t, and that bit will have to be cleared in software. the timer 0 and timer 1 flags, tf0 and tf1, are set at s5p2 of the cycle in which the timers overflow. the values are then polled by the circuitry in the next cycle. however, the timer 2 flag, tf2, is set at s2p2 and is polled in the same cycle in which the timer overflows. msb 6 5 4 3 2 1 lsb 1 2 3 4 5 6 7 8 msb * 65432 1 lsb sck cycle # (for reference) sck (cpol=0) sck (cpol=1) mosi (from master) miso (from slave) ss (to slave)
20 AT89S8252 0401g?micro?3/06 figure 10. interrupt sources table 10. interrupt enable (ie) register (msb)(lsb) ea ? et2 es et1 ex1 et0 ex0 enable bit = 1 enables the interrupt. enable bit = 0 disables the interrupt. symbol position function ea ie.7 disables all interrupts. if ea = 0, no inte rrupt is acknowledged. if ea = 1, each interrupt source is individually enabled or disabled by setting or clearing its enable bit. ? ie.6 reserved. et2 ie.5 timer 2 interrupt enable bit. es ie.4 spi and uart interrupt enable bit. et1 ie.3 timer 1 interrupt enable bit. ex1 ie.2 external interrupt 1 enable bit. et0 ie.1 timer 0 interrupt enable bit. ex0 ie.0 external interrupt 0 enable bit. user software should never write 1s to unimplemented bits, because they may be used in future at89 products.
21 AT89S8252 0401g?micro?3/06 oscillator characteristics xtal1 and xtal2 are the input and output, respectively, of an inverting amplifier that can be configured for use as an on-chip osci llator, as shown in figure 11. either a quartz crystal or ceramic resonator may be used. to drive the device from an external clock source, xtal2 should be left unconnected while xtal1 is driven, as shown in figure 12. there are no requirements on th e duty cycle of the external clock signal, since the input to the internal clocking circui try is through a divide-by-two flip-flop, but minimum and maximum voltage high and low time specifications must be observed. figure 11. oscillator connections note: c1, c2 = 30 pf 10 pf for crystals = 40 pf 10 pf for ceramic resonators figure 12. external clock drive configuration
22 AT89S8252 0401g?micro?3/06 idle mode in idle mode, the cpu puts itse lf to sleep while all the on-chip peripherals remain active. the mode is invoked by software. the content of the on-chip ram and all the special functions registers remain unchanged during this mode. the idle mode can be termi- nated by any enabled interrupt or by a hardware reset. note that when idle mode is terminated by a hardware reset, the device normally resumes program execution from where it left off, up to tw o machine cycles before the internal reset algorithm takes control. on-chip hardware inhibits access to internal ram in this event, but access to the port pins is not inhibited. to eliminate the possibility of an unexpected write to a port pin when idle mode is terminated by a reset, the instruction following the one that invokes idle mode should not write to a port pin or to external memory. power-down mode in the power-down mode, the oscillator is stopped and the instruction that invokes power-down is the last instruction executed. the on-chip ram and special function registers retain their values until the power-down mode is terminated. exit from power- down can be initiated either by a hardware reset or by an enabled external interrupt. reset redefines the sfrs but does not c hange the on-chip ram. the reset should not be activated before v cc is restored to its normal operating level and must be held active long enough to allow the osc illator to restart and stabilize. to exit power-down via an interrupt, the external interrupt must be enabled as level sen- sitive before entering power-down. the interrupt service routine starts at 16 ms (nominal) after the enabled interrupt pin is activated. program memory lock bits the AT89S8252 has three lock bits that can be left unprogrammed (u) or can be pro- grammed (p) to obtain the additional features listed in the following table. when lock bit 1 is programmed, the logic level at the ea pin is sampled and latched dur- ing reset. if the device is powered up without a reset, the latch initializes to a random value and holds that value until reset is activated. the latched value of ea must agree with the current logic level at that pin in order for the device to function properly. once programmed, the lock bits can only be unprogrammed with the chip erase opera- tions in either the parallel or serial modes. notes: 1. u = unprogrammed 2. p = programmed status of external pins duri ng idle and power-down modes mode program memory ale psen port0 port1 port2 port3 idle internal 1 1 data data data data idle external 1 1 float data address data power-down internal 0 0 data data data data power-down external 0 0 float data data data lock bit protection modes (1)(2) program lock bits protection type lb1 lb2 lb3 1 u u u no internal memory lock feature. 2 p u u movc instructions executed from external progra m memory are disabled from fetching code bytes from internal memory. ea is sampled and latched on reset and further programming of the flash memory (parallel or serial mode) is disabled. 3 p p u same as mode 2, but parallel or serial verify are also disabled. 4 p p p same as mode 3, but external execution is also disabled.
23 AT89S8252 0401g?micro?3/06 programming the flash and eeprom atmel?s AT89S8252 flash microcontroller offers 8k bytes of in-system reprogrammable flash code memory and 2k by tes of eeprom data memory. the AT89S8252 is normally shipped with t he on-chip flash code and eeprom data memory arrays in the erased state (i.e. contents = ffh) and ready to be programmed. this device supports a high-voltage (12-v v pp ) parallel programming mode and a low- voltage (5-v v cc ) serial programming mode. the serial programming mode provides a convenient way to reprogram the AT89S8252 inside the user?s system. the parallel pro- gramming mode is compatible with conventional third party flash or eprom programmers. the code and data memory arrays are mapped via separate address spaces in the serial programming mode. in the parallel programming mode, the two arrays occupy one contiguous address space: 0000h to 1fffh for the code array and 2000h to 27ffh for the data array. the code and data memory arrays on the AT89S8252 are programmed byte-by-byte in either programming mode. an auto-erase cycle is provided with the self-timed program- ming operation in the serial programming mode. there is no need to perform the chip erase operation to reprogram any memory location in the serial programming mode unless any of the lock bits have been programmed. in the parallel programming mode, there is no auto-erase cycle. to reprogram any non- blank byte, the user needs to use the chip erase operation first to erase both arrays. parallel programming algorithm: to program and verify the AT89S8252 in the paral- lel programming mode, the follo wing sequence is recommended: 1. power-up sequence: apply power between v cc and gnd pins. set rst pin to ?h?. apply a 3 mhz to 24 mhz clock to xtal1 pi n and wait for at le ast 10 milliseconds. 2. set psen pin to ?l? ale pin to ?h? ea pin to ?h? and all other pins to ?h?. 3. apply the appropriate combination of ?h? or ?l? logic levels to pins p2.6, p2.7, p3.6, p3.7 to select one of the programming operations shown in the flash programming modes table. 4. apply the desired byte address to pins p1.0 to p1.7 and p2.0 to p2.5. apply data to pins p0.0 to p0.7 for write code operation. 5. raise ea /v pp to 12v to enable flash programming, erase or verification. 6. pulse ale/prog once to program a byte in the code memory array, the data mem- ory array or the lock bits. the byte-write cycle is self-timed and typically takes 1.5 ms. 7. to verify the byte just programmed, bring pin p2.7 to ?l? and read the programmed data at pins p0.0 to p0.7. 8. repeat steps 3 through 7 changing the address and data for the entire 2k or 8k bytes array or until the end of the object file is reached. 9. power-off sequence: set xtal1 to ?l?. set rst and ea pins to ?l?. turn v cc power off.
24 AT89S8252 0401g?micro?3/06 in the parallel programming mode, there is no auto-erase cycle and to reprogram any non-blank byte, the user needs to use the chip erase operation first to erase both arrays. data polling: the AT89S8252 features data polling to indicate the end of a byte write cycle. during a byte write cycle in the parallel or serial programming mode, an attempted read of the last by te written will result in the co mplement of th e written datum on p0.7 (parallel mode), and on the msb of the serial output byte on miso (serial mode). once the write cycle has been complet ed, true data are valid on all outputs, and the next cycle may begin. data polling may begin any time after a write cycle has been initiated. ready/busy : the progress of byte programming in the parallel programming mode can also be monitored by the rdy/bsy output signal. pin p3.4 is pulled low after ale goes high during programming to indicate busy . p3.4 is pulled high again when program- ming is done to indicate ready. program verify: if lock bits lb1 and lb2 have not been programmed, the programmed code or data byte can be read back via the address and data lines for verification. the state of the lock bits can also be verified directly in the parallel programming mode. in the serial programming mode, the state of the lock bits can only be verified indirectly by observing that the lock bit features are enabled. chip erase: both flash and eeprom arrays are er ased electrically at the same time. in the parallel programming mode, chip erase is initiated by using the proper combina- tion of control signals and by holding ale/prog low for 10 ms. the code and data arrays are written with all ?1?s in the chip erase operation. in the serial programming mode, a chip erase operation is initiated by issuing the chip erase instruction. in this mode, chip erase is self-timed and takes about 16 ms. during chip erase, a serial read from any address locati on will return 00h at the data outputs. serial programming fuse: a programmable fuse is available to disable serial pro- gramming if the user needs maximum system security. the serial programming fuse can only be programmed or erased in the parallel programming mode. the AT89S8252 is shipped with the serial programming mode enabled. reading the signature bytes: the signature bytes are read by the same procedure as a normal verification of locations 030h and 031h, except that p3.6 and p3.7 must be pulled to a logic low. the values returned are as follows: (030h) = 1eh indicates manufactured by atmel (031h) = 72h indicates 89s8252 programming interface every code byte in the flash and eeprom arrays can be written, and the entire array can be erased, by using the appropriate combination of control signals. the write opera- tion cycle is self-timed and on ce initiated, will automatically time itself to completion. most worldwide major programming vendors offer support for the atmel at89 microcon- troller series. please contact your loca l programming vendor for the appropriate software revision.
25 AT89S8252 0401g?micro?3/06 serial downloading both the code and data memory arrays can be programmed using the serial spi bus while rst is pulled to v cc . the serial interface consists of pins sck, mosi (input) and miso (output). after rst is set high, the programming enable instruction needs to be executed first before program/er ase operations can be executed. an auto-erase cycle is built into the self-timed programming operation (in the serial mode only) and there is no need to first execute the chip erase instruction unless any of the lock bits have been programmed. the chip erase operation turns the content of every memory location in both the code and data arrays into ffh. the code and data memory arrays have separate address spaces: 0000h to 1fffh for code memory and 000h to 7ffh for data memory. either an external system clock is supplied at pin xtal1 or a crystal needs to be con- nected across pins xtal1 and xtal2. the maximum serial clock (sck) frequency should be less than 1/40 of the crystal fr equency. with a 24 mhz oscillator clock, the maximum sck frequency is 600 khz. serial programming algorithm to program and verify the AT89S8252 in the serial programming mode, the following sequence is recommended: 1. power-up sequence: apply power between vcc and gnd pins. set rst pin to ?h?. if a crystal is not connected across pins xtal1 and xtal2, apply a 3 mhz to 24 mhz clock to xtal1 pin and wa it for at least 10 milliseconds. 2. enable serial programming by sending the programming enable serial instruction to pin mosi/p1.5. the frequency of the shift clock supplied at pin sck/p1.7 needs to be less than the cpu clock at xtal1 divided by 40. 3. the code or data array is programmed one byte at a time by supplying the address and data together with the appropriate write instruction. the selected memory loca- tion is first automatically erased before new data is written. the write cycle is self- timed and typically takes less than 2.5 ms at 5v. 4. any memory location can be verified by using the read instruction which returns the content at the selected address at serial output miso/p1.6. 5. at the end of a programming session, rst can be set low to commence normal operation. 6. power-off sequence (if needed): set xtal1 to ?l? (if a crystal is not used). set rst to ?l?. turn v cc power off.
26 AT89S8252 0401g?micro?3/06 serial programming instruction the instruction set for serial programming follo ws a 3-byte protocol and is shown in the following table: notes: 1. data polling is used to indicate the end of a byte write cycle which typically takes less than 2.5 ms at 5v. 2. ?aaaaa? = high order address. 3. ?x? = don?t care. instruction set instruction input format operation byte 1 byte 2 byte 3 programming enable 1010 1100 0101 0011 xxxx xxxx enable serial programming interface after rst goes high. chip erase 1010 1100 xxxx x100 xxxx xxxx chip erase both 8k & 2k memory arrays. read code memory aaaa a001 low addr xxxx xxxx read data from code memory array at the selected address. the 5 msbs of the first byte are the high order address bits. the low order address bits are in the second byte. data are available at pin miso during the third byte. write code memory aaaa a010 low addr data in write data to code memory location at selected address. the address bits are the 5 msbs of the first byte together with the second byte. read data memory 00aa a101 low addr xxxx xxxx read data from data memory array at selected address. data are available at pin miso during the third byte. write data memory 00aa a110 low addr data in write data to data memory location at selected address. write lock bits 1010 1100 x x111 xxxx xxxx write lock bits. set lb1, lb2 or lb3 = ?0? to program lock bits. lb1 lb2 lb3
27 AT89S8252 0401g?micro?3/06 notes: 1. ?h? = weakly pulled ?high? internally. 2. chip erase and serial programming fuse require a 10 ms prog pulse. chip erase needs to be performed first before reprogramming any byte with a content other than ffh. 3. p3.4 is pulled low during programming to indicate rdy/bsy. 4. ?x? = don?t care flash and eeprom parallel programming modes mode rst psen ale/prog ea /v pp p2.6 p2.7 p3.6 p3.7 data i/o p0.7:0 address p2.5:0 p1.7:0 serial prog. modes h h (1) h (1) x chip erase h l 12v h l l l x x write (10k bytes) memory h l 12v l h h h din addr read (10k bytes) memory h l h 12v l l h h dout addr write lock bits: h l 12v h l h l din x bit - 1 p0.7 = 0 x bit - 2 p0.6 = 0 x bit - 3 p0.5 = 0 x read lock bits: h l h 12v h h l l dout x bit - 1 @p0.2 x bit - 2 @p0.1 x bit - 3 @p0.0 x read atmel code h l h 12v l l l l dout 30h read device code h l h 12v l l l l dout 31h serial prog. enable h l 12v l h l h p0.0 = 0 x serial prog. disable h l 12v l h l h p0.0 = 1 x read serial prog. fuse h l h 12v h h l h @p0.0 x (2) (2) (2)
28 AT89S8252 0401g?micro?3/06 figure 13. programming the flash/eeprom memory figure 14. verifying the flash/eeprom memory p1 p2.6 p3.6 p2.0 - p2.5 a0 - a7 addr. 0000h/27ffh see flash programming modes table 3-24 mhz a8 - a13 p0 +5v p2.7 pgm data prog v pp v ih ale p3.7 xtal2 ea rst rdy/ bsy p3.4 psen xtal1 gnd v cc AT89S8252 p1 p2.6 p3.6 p2.0 - p2.5 a0 - a7 addr. 0000h/2fffh see flash programming modes table 3-24 mhz a8 - a13 p0 +5v p2.7 pgm data (use 10k pullups) v i h v i h ale p3.7 xtal2 ea rst psen xtal1 gnd v cc AT89S8252 v pp figure 15. flash/eeprom serial downloading p1.7/sck data output instruction input clock in 3-24 mhz +4.0v to 6.0v p1.5/mosi v ih xtal2 rst xtal1 gnd v cc at89s52 p1.6/miso
29 AT89S8252 0401g?micro?3/06 flash/eeprom programming and veri fication waveforms ? parallel mode flash programming and verification characteristics ? parallel mode t a = 0c to 70c, v cc = 5.0v 10% symbol parameter min max units v pp programming enable voltage 11.5 12.5 v i pp programming enable current 1.0 ma 1/t clcl oscillator frequency 3 24 mhz t avgl address setup to prog low 48t clcl t ghax address hold after prog 48t clcl t dvgl data setup to prog low 48t clcl t ghdx data hold after prog 48t clcl t ehsh p2.7 (enable ) high to v pp 48t clcl t shgl v pp setup to prog low 10 s t glgh prog width 1 110 s t avqv address to data valid 48t clcl t elqv enable low to data valid 48t clcl t ehqz data float after enable 0 48t clcl t ghbl prog high to busy low 1.0 s t wc byte write cycle time 2.0 ms
30 AT89S8252 0401g?micro?3/06 serial downloading waveforms serial programming characteristics figure 16. serial programming timing serial clock input serial data input sck/p1.7 mosi/p1.5 miso/p1.6 serial data output 0 1 2 3 4 5 6 7 msb msb lsb lsb mosi miso sck t ovsh t shsl t slsh t shox table 11. serial programming characteristics, t a = -40 c to 85 c, v cc = 4.0 - 6.0v (unless otherwise noted) symbol parameter min typ max units 1/t clcl oscillator frequency 0 24 mhz t clcl oscillator period 41.6 ns t shsl sck pulse width high 24 t clcl ns t slsh sck pulse width low 24 t clcl ns t ovsh mosi setup to sck high t clcl ns t shox mosi hold after sck high 2 t clcl ns
31 AT89S8252 0401g?micro?3/06 z notes: 1. under steady state (n on-transient) conditions, i ol must be externally limited as follows: maximum i ol per port pin: 10 ma maximum i ol per 8-bit port: port 0: 26 ma; ports 1, 2, 3: 15 ma maximum total i ol for all output pins: 71 ma if i ol exceeds the test condition, v ol may exceed the related specification. pins are not guaranteed to sink current greater than the listed test conditions. 2. minimum v cc for power-down is 2v absolute maximum ratings* operating temperature.................................. -55c to +125c *notice: stresses beyond those listed under ?absolute maximum ratings? may cause permanent dam- age to the device. this is a stress rating only and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of this specification is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. storage temperature ..................................... -65c to +150c voltage on any pin with respect to ground .....................................-1.0v to +7.0v maximum operating voltage ............................................ 6.6v dc output current...................................................... 15.0 ma dc characteristics the values shown in this table are valid for t a = -40c to 85c and v cc = 5.0v 20%, unless otherwise noted. symbol parameter condition min max units v il input low-voltage (except ea ) -0.5 0.2 v cc - 0.1 v v il1 input low-voltage (ea ) -0.5 0.2 v cc - 0.3 v v ih input high-voltage (except xtal1, rst) 0.2 v cc + 0.9 v cc + 0.5 v v ih1 input high-voltage (xtal1, rst) 0.7 v cc v cc + 0.5 v v ol output low-voltage (1) (ports 1,2,3) i ol = 1.6 ma 0.5 v v ol1 output low-voltage (1) (port 0, ale, psen ) i ol = 3.2 ma 0.5 v v oh output high-voltage (ports 1,2,3, ale, psen ) i oh = -60 a, v cc = 5v 10% 2.4 v i oh = -25 a 0.75 v cc v i oh = -10 a 0.9 v cc v v oh1 output high-voltage (port 0 in external bus mode) i oh = -800 a, v cc = 5v 10% 2.4 v i oh = -300 a 0.75 v cc v i oh = -80 a 0.9 v cc v i il logical 0 input current (ports 1,2,3) v in = 0.45v -50 a i tl logical 1 to 0 transition current (ports 1,2,3) v in = 2v, v cc = 5v 10% -650 a i li input leakage current (port 0, ea ) 0.45 < v in < v cc 10 a rrst reset pull-down resistor 50 300 k ? c io pin capacitance test freq. = 1 mhz, t a = 25c 10 pf i cc power supply current active mode, 12 mhz 25 ma idle mode, 12 mhz 6.5 ma power-down mode (2) v cc = 6v 100 a v cc = 3v 40 a
32 AT89S8252 0401g?micro?3/06 ac characteristics under operating conditions, load capacitance for port 0, ale/prog , and psen = 100 pf; load capacitance for all other outputs = 80 pf. external program and data memory characteristics symbol parameter variable oscillator units min max 1/t clcl oscillator frequency 0 24 mhz t lhll ale pulse width 2t clcl - 40 ns t avll address valid to ale low t clcl - 13 ns t llax address hold after ale low t clcl - 20 ns t lliv ale low to valid instruction in 4t clcl - 65 ns t llpl ale low to psen low t clcl - 13 ns t plph psen pulse width 3t clcl - 20 ns t pliv psen low to valid instruction in 3t clcl - 45 ns t pxix input instruction hold after psen 0ns t pxiz input instruction float after psen t clcl - 10 ns t pxav psen to address valid t clcl - 8 ns t aviv address to valid instruction in 5t clcl - 55 ns t plaz psen low to address float 10 ns t rlrh rd pulse width 6t clcl - 100 ns t wlwh wr pulse width 6t clcl - 100 ns t rldv rd low to valid data in 5t clcl - 90 ns t rhdx data hold after rd 0ns t rhdz data float after rd 2t clcl - 28 ns t lldv ale low to valid data in 8t clcl - 150 ns t avdv address to valid data in 9t clcl - 165 ns t llwl ale low to rd or wr low 3t clcl - 50 3t clcl + 50 ns t avwl address to rd or wr low 4t clcl - 75 ns t qvwx data valid to wr transition t clcl - 20 ns t qvwh data valid to wr high 7t clcl - 120 ns t whqx data hold after wr t clcl - 20 ns t rlaz rd low to address float 0 ns t whlh rd or wr high to ale high t clcl - 20 t clcl + 25 ns
33 AT89S8252 0401g?micro?3/06 external program memory read cycle external data memory read cycle
34 AT89S8252 0401g?micro?3/06 external data memory write cycle external clock drive waveforms external clock drive symbol parameter v cc = 4.0v to 6.0v units min max 1/t clcl oscillator frequency 0 24 mhz t clcl clock period 41.6 ns t chcx high time 15 ns t clcx low time 15 ns t clch rise time 20 ns t chcl fall time 20 ns
35 AT89S8252 0401g?micro?3/06 shift register mode timing waveforms ac testing input/output waveforms (1) note: 1. ac inputs during testing are driven at v cc - 0.5v for a logic 1 and 0.45v for a logic 0. timing measurements are made at v ih min. for a logic 1 and v il max. for a logic 0. float waveforms (1) note: 1. for timing purposes, a port pin is no longer floating when a 100 mv change from load voltage occurs. a port pin begins t o float when a 100 mv change from the loaded v oh /v ol level occurs. serial port timing: shift register mode test conditions the values in this table are valid for v cc = 4.0v to 6v and load capacitance = 80 pf. symbol parameter variable oscillator units min max t xlxl serial port clock cycle time 12t clcl s t qvxh output data setup to clock rising edge 10t clcl - 133 ns t xhqx output data hold after clock rising edge 2t clcl - 117 ns t xhdx input data hold after clock rising edge 0 ns t xhdv clock rising edge to input data valid 10t clcl - 133 ns
36 AT89S8252 0401g?micro?3/06 AT89S8252 typical icc (active) at 25c 0 4 8 12 16 20 24 0 4 8 12 16 20 24 f (mhz) v = 6.0v cc v = 5.0v cc i c c m a AT89S8252 typical icc (idle) at 25c 0.0 0.8 1.6 2.4 3.2 4.0 4.8 0 4 8 12 16 20 24 f (mhz) v= cc v= cc 6.0v 5.0v i c c m a notes: 1. xtal1 tied to gnd for icc (power-down) 2. lock bits programmed
37 AT89S8252 0401g?micro?3/06 ordering information speed (mhz) power supply ordering code package operation range 24 4.0v to 6.0v AT89S8252-24ac AT89S8252-24jc AT89S8252-24pc 44a 44j 40p6 commercial (0 c to 70 c) 4.0v to 6.0v AT89S8252-24ai AT89S8252-24ji AT89S8252-24pi 44a 44j 40p6 industrial (-40 c to 85 c) package type 44a 44-lead, thin plastic gull wing quad flatpack (tqfp) 44j 44-lead, plastic j-leaded chip carrier (plcc) 40p6 40-lead, 0.600" wide, plastic dual inline package (pdip)
38 AT89S8252 0401g?micro?3/06 packaging information 44a ? tqfp 2325 orchard parkway san jose, ca 95131 title drawing no. r rev. 44a, 44-lead, 10 x 10 mm body size, 1.0 mm body thickness, 0.8 mm lead pitch, thin profile plastic quad flat package (tqfp) b 44a 10/5/2001 pin 1 identifier 0?~7? pin 1 l c a1 a2 a d1 d e e1 e b common dimensions (unit of measure = mm) symbol min nom max note notes: 1. this package conforms to jedec reference ms-026, variation acb. 2. dimensions d1 and e1 do not include mold protrusion. allowable protrusion is 0.25 mm per side. dimensions d1 and e1 are maximum plastic body size dimensions including mold mismatch. 3. lead coplanarity is 0.10 mm maximum. a ? ? 1.20 a1 0.05 ? 0.15 a2 0.95 1.00 1.05 d 11.75 12.00 12.25 d1 9.90 10.00 10.10 note 2 e 11.75 12.00 12.25 e1 9.90 10.00 10.10 note 2 b 0.30 ? 0.45 c 0.09 ? 0.20 l 0.45 ? 0.75 e 0.80 typ
39 AT89S8252 0401g?micro?3/06 44j ? plcc notes: 1. this package conforms to jedec reference ms-018, variation ac. 2. dimensions d1 and e1 do not include mold protrusion. allowable protrusion is .010"(0.254 mm) per side. dimension d1 and e1 include mold mismatch and are measured at the extreme material condition at the upper or lower parting line. 3. lead coplanarity is 0.004" (0.102 mm) maximum. a 4.191 ? 4.572 a1 2.286 ? 3.048 a2 0.508 ? ? d 17.399 ? 17.653 d1 16.510 ? 16.662 note 2 e 17.399 ? 17.653 e1 16.510 ? 16.662 note 2 d2/e2 14.986 ? 16.002 b 0.660 ? 0.813 b1 0.330 ? 0.533 e 1.270 typ common dimensions (unit of measure = mm) symbol min nom max note 1.14(0.045) x 45? pin no. 1 identifier 1.14(0.045) x 45? 0.51(0.020)max 0.318(0.0125) 0.191(0.0075) a2 45? max (3x) a a1 b1 d2/e2 b e e1 e d1 d 44j , 44-lead, plastic j-leaded chip carrier (plcc) b 44j 10/04/01 2325 orchard parkway san jose, ca 95131 title drawing no. r rev.
40 AT89S8252 0401g?micro?3/06 40p6 ? pdip 2325 orchard parkway san jose, ca 95131 title drawing no. r rev. 40p6 , 40-lead (0.600"/15.24 mm wide) plastic dual inline package (pdip) b 40p6 09/28/01 pin 1 e1 a1 b ref e b1 c l seating plane a 0o ~ 15o d e eb common dimensions (unit of measure = mm) symbol min nom max note a ? ? 4.826 a1 0.381 ? ? d 52.070 ? 52.578 note 2 e 15.240 ? 15.875 e1 13.462 ? 13.970 note 2 b 0.356 ? 0.559 b1 1.041 ? 1.651 l 3.048 ? 3.556 c 0.203 ? 0.381 eb 15.494 ? 17.526 e 2.540 typ notes: 1. this package conforms to jedec reference ms-011, variation ac. 2. dimensions d and e1 do not include mold flash or protrusion. mold flash or protrusion shall not exceed 0.25 mm (0.010").
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