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rev. b information furnished by analog devices is believed to be accurate and reliable. however, no responsibility is assumed by analog devices for its use, nor for any infringements of patents or other rights of third parties which may result from its use. no license is granted by implication or otherwise under any patent or patent rights of analog devices. a admc331 one technology way, p.o. box 9106, norwood, ma 02062-9106, u.s.a. tel: 781/329-4700 world wide web site: http://www.analog.com fax: 781/326-8703 ? analog devices, inc., 2000 single chip dsp motor controller functional block diagram arithmetic units shifter mac alu memory sport 1 timer data ram 1k 16 program rom 2k 24 program ram 2k 24 watch- dog timer 24-bit pio 16-bit 3-phase pwm 7 analog inputs 2 8 bit aux pwm adsp-2100 base architecture serial ports program sequencer data address generators dag 1 dag 2 program memory address data memory address program memory data data memory data sport 0 target applications washing machines, refrigerator compressors, fans, pumps, industrial variable speed drives features 26 mips fixed-point dsp core single cycle instruction execution (38.5 ns) adsp-2100 family code compatible independent computational units alu multiplier/accumulator barrel shifter multifunction instructions single cycle context switch powerful program sequencer zero overhead looping conditional instruction execution two independent data address generator memory configuration 2k 24-bit program memory ram 2k 24-bit program memory rom 1k 16-bit data memory ram three-phase 16-bit pwm generator 16-bit center-based pwm generator programmable deadtime and narrow pulse deletion edge resolution to 38.5 ns 198 hz minimum switching frequency double/single duty cycle update mode control programmable pwm pulsewidth suitable for ac induction and synchronous motors special signal generation for switched reluctance motors special crossover function for brushless dc motors individual enable and disable for all pwm outputs high frequency chopping mode for transformer coupled gate drives hardwired polarity control external pwmtrip pin seven analog input channels acquisition synchronized to pwm switching frequency conversion speed control 24 bits of digital i/o port bit configurable as input or output change of state interrupt support two 8-bit auxiliary pwm timers synchronized analog output programmable frequency 0% to 100% duty cycle (continued on page 7)
C2C rev. b admc331?pecifications (v dd = +5 v 10%, gnd = sgnd = 0 v, t a = ?0 c to +85 c, unless otherwise noted) parameter min typ max units conditions/comments analog-to-digital converter charging capacitor = 1000 pf 2.5 khz sample frequency signal input 0.3 3.3 1 v resolution 12 2 bits no missing codes converter linearity 2 12 lsbs zero offset 5 50 mv channel-to-channel comparator match 22 mv comparator delay 600 ns current source 10.16 12.7 15.24 a current source linearity 2 % electrical characteristics v il logic low 0.8 v v ih logic high 2 v v ol low level output voltage 0.4 v i ol = 2 ma v ol low level output voltage (xtal) 0.5 v i ol = 2 ma v oh high level output voltage 4 v i oh = 0.5 ma i il low level input current ?0 av in = 0 v i ih high level input current 10 av in = v dd i ih hi-level pwmtrip , pio0?io23 current 100 a@ v dd = max, v in = v dd max i ih hi-level pwmpol/ pwmsr current 10 a@ v dd = max, v in = v dd max i il lo-level pwmtrip , pio0?io23 current 10 a@ v dd = max, v in = 0 v i il lo-level pwmpol/ pwmsr current 100 a@ v dd = max, v in = 0 v i dd supply current (dynamic) 120 ma 13 mhz dsp clock i dd supply current (idle) 60 ma 13 mhz dsp clock reference voltage output voltage level 2.2 2.55 2.9 v 100 a load output voltage change t min to t max 20 mv 16-bit pwm timer counter resolution 16 bits edge resolution (single update mode) 76.9 ns 13 mhz clkin edge resolution (double update mode) 38.5 ns 13 mhz clkin programmable deadtime range 0 78 s 13 mhz clkin programmable deadtime increments 76.9 ns 13 mhz clkin programmable pulse deletion range 0 78 s 13 mhz clkin programmable pulse deletion increments 76.9 ns 13 mhz clkin pwm frequency range 0.198 khz 13 mhz clkin pwmsync pulsewidth (t crst ) 0.077 9.8 s 13 mhz clkin gate drive chop frequency range 0.02 6.5 mhz 13 mhz clkin auxiliary pwm timers resolution 8 bits pwm frequency 0.051 6.5 mhz 13 mhz clkin notes 1 signal input max v = 3.5 v if v dd = 5 v 5%. 2 resolution varies with pwm switching frequency (13 mhz clock in double update mode), 50.7 khz = 9 bits, 6.3 khz = 12 bits. specifications subject to change without notice.
admc331 C3C rev. b timing parameters parameter min max unit clock signals t ck is defined as 0.5 t cki . the admc331 uses an input clock with a frequency equal to half the instruction rate; a 13 mhz input clock (which is equivalent to 76.9 ns) yields a 38.5 ns processor cycle (equivalent to 26 mhz). t ck values within the range of 0.5 t cki period should be substituted for all relevant timing parameters to obtain specification value. example: t ckh = 0.5 t ck ?10 ns = 0.5 (38.5 ns) ?10 ns = 9.25 ns. timing requirements : t cki clkin period 76.9 150 ns t ckil clkin width low 20 ns t ckih clkin width high 20 ns switching characteristics : t ckl clkout width low 0.5 t ck ?10 ns t ckh clkout width high 0.5 t ck ?10 ns t ckoh clkin high to clkout high 0 20 ns control signals timing requirement: t rsp reset width low 5 t ck 1 ns pwm shutdown signals timing requirement: t pwmtpw pwmtrip width low 2 t ck ns note 1 applies after power-up sequence is complete. internal phase lock loop requires no more than 2000 clkin cycles assuming stable c lkin (not including crystal oscillator start-up time). clkin clkout t ckoh t cki t ckih t ckh t ckl t ckil figure 1. clock signals
admc331 C4C rev. b parameter min max unit serial ports timing requirements: t sck sclk period 100 ns t scs dr/tfs/rfs setup before sclk low 15 ns t sch dr/tfs/rfs hold after sclk low 20 ns t scp sclk in width 40 ns switching characteristics : t cc clkout high to sclk out 0.25 t ck 0.25 t ck + 20 ns t scde sclk high to dt enable 0 ns t scdv sclk high to dt valid 30 ns t rh tfs/rfs out hold after sclk high 0 ns t rd tfs/rfs out delay from sclk high 30 ns t scdh dt hold after sclk high 0 ns t scdd sclk high to dt disable 30 ns t tde tfs (alt) to dt enable 0 ns t tdv tfs (alt) to dt valid 25 ns t rdv rfs (multichannel, frame delay zero) to dt valid 30 ns t cc t cc t sch t scs t rd t rh t scp t scp t sck t scdv t scde t scdh t scdd t tde t tdv t rdv clkout sclk dr rfs in tfs in rfs out tfs out dt tfs (alternate frame mode) rfs (multichannel mode, frame delay 0 [mfd = 0]) figure 2. serial ports
admc331 C5C rev. b absolute maximum ratings* supply voltage (v dd ) . . . . . . . . . . . . . . . . . . ?.3 v to +7.0 v supply voltage (av dd ) . . . . . . . . . . . . . . . . . ?.3 v to +7.0 v input voltage . . . . . . . . . . . . . . . . . . . . ?.3 v to v dd + 0.3 v output voltage swing . . . . . . . . . . . . . . ?.3 v to v dd + 0.3 v operating temperature range (ambient) . . . 40 c to +85 c storage temperature range . . . . . . . . . . . . ?5 c to +150 c lead temperature (5 sec) . . . . . . . . . . . . . . . . . . . . . . +280 c *stresses greater than those listed above may cause permanent damage to the device. these are stress ratings only; functional operation of the device at these or any other conditions greater than 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. ordering guide temperature instruction package package model range rate description option admc331bst ?0 c to +85 c 26 mhz 80-lead plastic thin quad flatpack (tqfp) st-80 admc331-advevalkit development tool kit ADMC331-PB evaluation/processor board caution esd (electrostatic discharge) sensitive device. electrostatic charges as high as 4000 v readily accumulate on the human body and test equipment and can discharge without detection. although the admc331 features proprietary esd protection circuitry, permanent damage may occur on devices subjected to high-energy electrostatic discharges. therefore, proper esd precautions are recommended to avoid performance degradation or loss of functionality. warning! esd sensitive device
admc331 C6C rev. b pin pin pin no. type name 1 o/p vref 2 sup av dd 3 gnd gnd 4 bidir pio9 5 bidir pio8 6 bidir pio7 7 bidir pio6 8 bidir pio5 9 bidir pio4 10 bidir pio3 11 bidir pio2 12 bidir pio1 13 bidir pio0 14 o/p aux1 15 o/p aux0 16 bidir pio10 17 bidir pio11 18 sup v dd 19 i/p pwmtrip 20 gnd gnd pin function descriptions pin pin pin no. type name 21 sup v dd 22 gnd gnd 23 bidir pio12 24 bidir pio13 25 o/p pwmsync 26 o/p cl 27 o/p ch 28 o/p bl 29 o/p bh 30 o/p al 31 o/p ah 32 bidir pio14 33 bidir pio15 34 bidir pio16 35 sup v dd 36 gnd gnd 37 bidir pio17 38 gnd gnd 39 bidir pio18 40 gnd gnd pin pin pin no. type name 41 gnd gnd 42 gnd gnd 43 o/p xtal 44 i/p clkin 45 i/p pwmpol 46 i/p reset 47 gnd gnd 48 sup v dd 49 bidir pio19 50 bidir pio20 51 o/p clkout 52 gnd gnd 53 o/p dt1 54 bidir tfs1 55 bidir rfs1/ srom 56 i/p dr1a 57 i/p dr1b 58 bidir sclk1 59 o/p dt0 60 i/p pwmsr pin pin pin no. type name 61 bidir tfs0 62 bidir rfs0 63 i/p dr0 64 bidir sclk0 65 bidir pio21 66 bidir pio22 67 bidir pio23 68 sup v dd 69 gnd gnd 70 gnd agnd 71 i/p capin 72 o/p iconst 73 gnd sgnd 74 i/p v1 75 i/p v2 76 i/p v3 77 i/p vaux0 78 i/p vaux1 79 i/p vaux2 80 i/p vaux3 pin configuration 80-lead plastic thin quad flatpack (tqfp) (st-80) 80 79 78 77 76 75 74 73 72 71 70 69 68 67 66 65 64 63 62 61 56 57 58 59 54 55 52 53 50 51 60 45 46 47 48 43 44 42 49 41 5 4 3 2 7 6 9 8 1 11 10 16 15 14 13 18 17 20 19 12 pin 1 identifier top view (not to scale) 40 39 38 37 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 36 vaux3 vaux2 vaux1 vaux0 v3 v2 v1 sgnd iconst capin agnd gnd v dd pio23 pio22 pio21 sclk0 dr0 rfs0 tfs0 v dd gnd pio12 pio13 pwmsync cl ch bl bh al ah pio14 pio15 pio16 v dd gnd pio17 gnd pio18 pwmsr dt0 sclk1 dr1b dr1a rfs1/ srom tfs1 dt1 gnd clkout pio20 pio19 v dd gnd reset pwmpol clkin xtal gnd gnd vref av dd gnd pio9 pio8 pio7 pio6 pio5 pio4 pio3 pio2 pio1 pio0 aux0 aux1 pio10 pio11 v dd pwmtrip gnd gnd admc331
admc331 C7C rev. b ( continued from page 1) two programmable operational modes independent mode offset mode 16-bit watchdog timer programmable 16-bit internal timer with prescaler two double buffered synchronous serial ports four boot load protocols via sport1 e 2 prom/srom booting uart booting (sci compatible) with autobaud feature synchronous master booting with autobaud feature synchronous slave booting with autobaud feature debugger interface via sport1 with autobaud (uart and synchronous supported) rom utilities full debugger for program development preprogrammed math functions preprogrammed motor control functionsvector transformations 80-lead tqfp package industrial temperature range C40 c to +85 c general description the admc331 is a low cost, single-chip dsp-based controller, suitable for ac induction motors, permanent magnet synchro- nous motors, brushless dc motors, and switched reluctance motors. the admc331 integrates a 26 mips, fixed-point dsp core with a complete set of motor control peripherals that per- mits fast, efficient development of motor controllers. the dsp core of the admc331 is the adsp-2171, which is completely code compatible with the adsp-2100 dsp family and combines three computational units, data address genera- tors and a program sequencer. the computational units com- prise an alu, a multiplier/accumulator (mac) and a barrel shifter. the adsp-2171 adds new instructions for bit manipula- tion, multiplication (x squared), biased rounding and global interrupt masking. in addition, two flexible, double-buffered, bidirectional, synchronous serial ports are included in the admc331. the admc331 provides 2k 24-bit program memory ram, 2k 24-bit program memory rom and 1k 16-bit data memory ram. the program and data memory ram can be boot loaded through the serial port from a serial rom (srom), e 2 prom, asynchronous (uart) connection or synchronous connection. the program mem ory rom includes a monitor that adds software debugging features through the serial port. in addition, a number of preprogrammed mathematical and motor control functions are included in the program memory rom. the motor control peripherals of the admc331 include a 16-bit center-based pwm generation unit that can be used to produce high accuracy pwm signals with minimal processor overhead and seven analog input channels. the device also contains two auxiliary 8-bit pwm channels, a 16-bit watch- dog timer and expanded capability through the serial ports and 24-bit digital i/o ports.
admc331 C8C rev. b bus exchange data address generator #2 data address generator #1 14 14 24 16 6 r bus 16 companding circuitry dma bus pma bus dmd bus pmd bus program sequencer instruction register input regs output regs shifter input regs output regs mac input regs output regs alu serial port 0 receive reg transmit reg control logic dm ram 1k 16 pm rom 2k 24 pm ram 2k 24 serial port 1 receive reg transmit reg 5 timer figure 3. dsp core block diagram dsp core architecture overview figure 3 is an overall block diagram of the dsp core of the admc331, which is based on the fixed-point adsp-2171. the flexible architecture and comprehensive instruction set of the adsp-2171 allows the processor to perform multiple operations in parallel. in one processor cycle (38.5 ns with a 13 mhz clkin) the dsp core can: ? generate the next program address. ? fetch the next instruction. ? perform one or two data moves. ? update one or two data address pointers. ? perform a computational operation. this all takes place while the processor continues to: ? receive and transmit through the serial ports. ? decrement the interval timer. ? generate three-phase pwm waveforms for a power inverter. ? generate two signals using the 8-bit auxiliary pwm timers. ? acquire four analog signals. ? decrement the watchdog timer. the processor contains three independent computational units: the arithmetic and logic unit (alu), the multiplier/accumulator (mac) and the shifter. the computational units process 16-bit data directly and have provisions to support multiprecision com- putations. the alu performs a standard set of arithmetic and logic operations; division primitives are also supported. the mac performs single-cycle multiply, multiply/add, multiply/ subtract operations with 40 bits of accumulation. the shifter performs logical and arithmetic shi fts, normalization, denormalization and derive exponent operations. the shifter can be used to effi- ciently implement numeric format control including floating- point representations. the internal result (r) bus directly connects the computational units so that the output of any unit may be the input of any unit on the next cycle. a powerful program sequencer and two dedicated data address generators ensure efficient delivery of operands to these computa- tional units. the sequencer supports conditional jumps and subroutine calls and returns in a single cycle. with internal loop counters and loop stacks, the admc331 executes looped code with zero overhead; no explicit jump instructions are required to maintain the loop. two data address generators (dags) provide addresses for simultaneous dual operand fetches from data memory and program memory. each dag maintains and updates four ad- dress pointers (i registers). whenever the pointer is used to access data (indirect addressing), it is post-modified by the value in one of four modify (m registers). a length value may be associated with each pointer (l registers) to implement auto- matic modulo addressing for circular buffers. the circular buff- ering feature is also used by the serial ports for automatic data transfers to and from on-chip memory. dag1 generates only data memory address but provides an optional bit-reversal capability. dag2 may generate either program or data memory addresses, but has no bit-reversal capability. efficient data transfer is achieved with the use of five internal buses: ? program memory address (pma) bus ? program memory data (pmd) bus ? data memory address (dma) bus ? data memory data (dmd) bus ? result (r) bus
admc331 C9C rev. b program memory can store both instructions and data, permit- ting the admc331 to fetch two operands in a single cycle one from program memory and one from data memory. the admc331 can fetch an operand from on-chip program memory and the next instruction in the same cycle. the admc331 writes data from its 16-bit registers to the 24-bit program memory using the px register to provide the lower eight bits. when it reads data (not instructions) from 24-bit program memory to a 16-bit data register, the lower eight bits are placed in the px register. the admc331 can respond to a number of distinct dsp core and peripheral interrupts. the dsp core interrupts include serial port receive and transmit interrupts, timer interrupts, software interrupts and external interrupts. the motor control peripherals also produce interrupts to the dsp core. the two serial ports (sports) provide a complete synchronous serial interface with optional companding in hardware and a wide variety of framed and unframed data transmit and receive modes of operation. each sport can generate an internal programmable serial clock or accept an external serial clock. boot loading of both the program and data memory ram of the admc331 is through the serial port sport1. a programmable interval counter is also included in the dsp core and can be used to generate periodic interrupts. a 16-bit count register (tcount) is decremented every n processor cycle, where n? is a scaling value stored in the 8-bit tscale register. when the value of the counter reaches zero, an interrupt is generated and the count register is reloaded from a 16-bit pe- riod register (tperiod). the admc331 instruction set provides flexible data moves and multifunction (one or two data moves with a computation) instruc- tions. each instruction is executed in a single 38.5 ns processor cycle (for a 13 mhz clkin). the admc331 assembly lan- guage uses an algebraic syntax for ease of coding and readabil- ity. a comprehensive set of development tools support program development. for further information on the dsp core, refer to the adsp-2100 family user? manual, third edition , with par- ticular reference to the adsp-2171. serial ports the admc331 incorporates two complete synchronous serial ports (sport0 and sport1) for serial communication and multiprocessor communication. following is a brief list of capa- bilities of the admc331 sports. refer to the adsp-2100 family user? manual, third edition, for further details. sports are bidirectional and have a separate, double-buffered transmit and receive section. sports can use an external serial clock or generate their own serial clock internally. sports have independent framing for the receive and trans- mit sections. sections run in a frameless mode or with f rame synchronization signals internally or externally generated. frame synchronization signals are active high or inverted, with either of two pulsewidths and timings. sports support serial data word lengths from 3 bits to 16 bits and provide optional a-law and -law companding ac- cording to itu (formerly ccitt) recommendation g.711. sport receive and transmit sections can generate unique interrupts on completing a data word transfer. sports can receive and transmit an entire circular buffer of data with only one overhead cycle per data word. an interrupt is generated after a data buffer transfer. sport0 has a multichannel interface to selectively receive and transmit a 24-word or 32-word, time-division multi- plexed, serial bitstream. sport1 can be configured to have two external interrupts ( irq0 and irq1 ), and the flag in and flag out signals. the internally generated serial clock may still be used in this con- figuration. sport1 is the default input for program and data memory boot loading. the rfs1 pin can be configured internal to the admc331 as an srom/e 2 prom reset signal. sport1 has two data receive pins (dr1a and dr1b). the dr1a pin is intended for synchronous boot loading from the external srom/e 2 prom. the dr1b pin can be used as the data receive pin for boot loading from an external asynchro- nous (uart) connection (sci compatible), an external synchronous connection as the data receive pin for an external device communicating over the debugger interface, or as the data receive pin for a general purpose sport after booting. these two pins are internally multiplexed onto the one dr1 port of the sport. the particular data r eceive pin selected is determined by a bit in the modectrl register.
admc331 C10C rev. b pin function description the admc331 is available in an 80-lead tqfp package. table i contains the pin descriptions. table i. pin list pin # group of input/ name pins output function reset 1 i/p processor reset input. sport0 5 i/p, o/p serial port 0 pins (tfs0, rfs0, dt0, dr0, sclk0). sport1 6 i/p, o/p serial port 1 pins (tfs1, rfs1, dt1, dr1a, dr1b, sclk1). clkout 1 o/p processor clock output. clkin, xtal 2 i/p, o/p external cl ock or quartz cr ystal connection point. pio0?io23 24 i/p, o/p digital i/o port pins. aux0?ux1 2 o/p auxiliary pwm outputs. ah?l 6 o/p pwm outputs. pwmtrip 1 i/p pwm trip signal. pwmpol 1 i/p pwm polarity pin. pwmsync 1 o/p pwm synchronization pin. pwmsr 1 i/p switch reluctance mode pin. v1?3, 3 i/p analog inputs. vaux0?aux3 4 i/p auxiliary analog input capin 1 i/p adc capacitor input. iconst 1 o/p adc constant current source. vref 1 o/p voltage reference output. av dd 1 analog power supply. agnd 1 analog ground. sgnd 1 analog signal ground v dd 5 digital power supply. gnd 11 digital ground. interrupt overview the admc331 can respond to 34 different interrupt sources with minimal overhead, 8 of which are internal dsp core interrupts and 26 interrupts from the motor control perip herals. the 8 dsp core interrupts are sport0 receive and transmit, sport1 receive (or irq0 ) and transmit (or irq1 ), the internal timer and two software interrupts. the motor control peripheral interrupts are the 24 peripheral i/os and two from the pwm (pwms ync pulse and pwmtrip ). all motor control inter- rupts are multiplexed into the dsp core through the peripheral irq2 interrupt. the interrupts are internally prioritized and indi- vidually m askable. a detailed description of the entire inter- rupt system of the admc331 is given later, following a more detailed description of each peripheral block. memory map the admc331 has two distinct memory types: program memory and data memory. in general, program memory contains user code and coefficients, while the data memory is used to store variables and data during program execution. both program memory ram and rom are provided on the admc331. pro- gram memory ram is arranged as one contiguous 2k 24-bit block, starting at address 0x0000. program memory rom is located at address 0x0800. data memory is arranged as a 1k 16-bit block starting at address 0x3800. the motor control peripherals are memory mapped into a region of the data memory space starting at 0x2000. the complete program and data memory maps are given in tables ii and iii, respectively. table ii. program memory map memory address range type function 0x0000?x002f ram interrupt vector table 0x0030?x071f ram user program space 0x0720?x07ec ram reserved by debugger 0x07ed?x07ff ram reserved by monitor 0x0800?x0dec rom rom monitor 0x0ded?x0fea rom rom math and motor control utilities 0x0feb?x0fff rom reserved table iii. data memory map memory address range type function 0x0000?x1fff reserved 0x2000?x20ff memory mapped registers 0x2100?x37ff reserved 0x3800?x3b5f ram user data space 0x3b60?x3bff ram reserved by monitor 0x3c00?x3fff memory mapped registers rom code the 2k 24-bit block of program memory rom starting at ad- dress 0x0800 contains a monitor function that is used to download and execute user programs via the serial port. in addition, the monitor function supports an interactive mode in which commands are received and processed from a host. an example of such a host is the windows -based motion control debugger, which is part of the software development system for the admc331. in the inter- active mode, the host can access both the internal dsp and periph- eral motor control registers of the admc331, read and write to both program and data memory, implement breakpoints and per- form single-step and run/halt operation as part of the program debugging cycle. in addition to the monitor function, the program memory rom contains a number of useful mathematical and motor control util- ities that can be called as subroutines from the user code. a com- plete list of these rom functions is given in table iv. the start address of the function in the program memory rom is also given. refer to the admc331 dsp motor controller devel oper? reference manual for more details of the rom functions. windows is a registered trademark of microsoft corporation.
admc331 C11C rev. b table iv. rom utilities utility address function per_rst 0x07f1 reset peripherals. umask 0x0ded limits unsigned value to given range. put_vector 0x0df4 facilitates user setup of vector table. smask 0x0e06 limits signed value to given range. admc_cos 0x0e26 cosine function. admc_sin 0x0e2d sine function. arctan 0x0e43 arctangent function. reciprocal 0x0e65 reciprocal (1/ ) function. sqrt 0x0e7b square root function. ln 0x0eb5 natural logarithm function. log 0x0eb8 l ogarithm (base 10) function. fltone 0x0ed4 fixed pt. to float conversion. fixone 0x0ed9 float to fixed pt. conversion. fpa 0x0edd floating pt. addition. fps 0x0eec floating pt. subtraction. fpm 0x0efc floating pt. multiplication. fpd 0x0f05 floating pt. division. fpmacc 0x0f26 floating pt. mu ltiply /accumulate. park 0x0f48 forwa rd/reverse park transformation. rev_clark 0x0f5c reverse clark transformation. for_clark 0x0f72 forward clark transform ation. cos64 0x0f80 64 pt. cos table. one_by_x 0x0fco 16 pt. 1/ table. sdivqint 0x0fd0 unsigned single precision division (integer). sdivq 0x0fd9 unsigned single precision division (fractional). system interface figure 4 shows a basic system configuration for the admc331, with an external crystal and serial e 2 prom for boot loading of program and data memory ram. admc331 xtal clkin dr1a sclk1 rfs1/ srom data clk reset 13 mhz clkout reset serial e 2 prom figure 4. basic system configuration clock signals the admc331 can be clocked by either a crystal or a ttl- compatible clock signal. the clkin input cannot be halted, changed during operation nor operated below the specified minimum frequency during normal operation. if an external clock is used, it should be a ttl-compatible signal running at half the instruction rate. the signal is connected to the clkin pin of the admc331. in this mode, with an external clock signal, the xtal pin must be left unconnected. the admc331 uses an input clock with a frequency equal to half the instruc- tion rate; a 13 mhz input clock yields a 38.5 ns processor cycle (which is equivalent to 26 mhz). normally, instructions are executed in a single processor cycle. all device timing is relative to the internal instruction rate, which is indicated by the clkout signal. because the admc331 includes an on-chip oscillator feedback circuit, an external crystal may be used instead of a clock source, as shown in figure 4. the crystal should be connected across the clkin and xtal pins, with two capacitors as shown in figure 4. a parallel-resonant, fundamental frequency, microprocessor-grade crystal should be used. a clock output signal (clkout) is generated by the processor at the processors cycle rate of twice the input frequency. this output can be enabled and disabled by the clkodis bit of the sport0 autobuffer control register, dm[0x3ff3]. however, extreme care must be exercised when using this bit since disabling clkout effectively disables all motor control peripherals, except the watchdog timer. reset the reset signal initiates a master reset of the admc331. the reset signal must be asserted during the power-up se- quence to assure proper initialization. reset during initial power-up must be held long enough to allow the internal clock to stabilize. if reset is activated any time after power-up, the clock continues to run and does not require stabilization time. the power-up sequence is defined as the total time required for the crystal oscillator circuit to stabilize after a valid v dd is ap- plied to the processor, and for the internal phase-locked loop (pll) to lock onto the specific crystal frequency. a minimum of 2000 clkin cycles ensures that the pll has locked, but does not include the crystal oscillator start-up time. during this power-up sequence, the reset signal should be held low. on any subsequent resets, the reset signal must meet the mini- mum pulsewidth specification, t rsp . if an rc circuit is used to generate the reset signal, the use of an external schmitt trigger is recommended. the master reset sets all internal stack pointers to the empty stack condition, masks all interrupts, initializes dsp core regis- ters and performs a full reset of all of the motor control periph- erals. when the reset line is released, the first instruction is fetched from internal program memory rom at location 0x0800. the internal monitor code at this location then commences the boot-loading sequence over the serial port, sport1. a soft- ware controlled full peripheral reset is achieved by toggling the dsp fl2 flag from 1 to 0 to 1 again.
admc331 C12C rev. b boot loading on power-up or reset, the admc331 is configured so that execution begins at the internal pm rom at address 0x0800. this starts execution of the internal monitor function that first performs some initialization functions and copies a default inter- rupt vector table to addresses 0x0000?x002f of program memory ram. the monitor next attempts to boot load from an external srom or e 2 prom on sport1 using the three wire connec- tion of figure 4. the monitor program first toggles the rfs1/ srom pin of the admc331 to reset the serial memory device. if an srom or e 2 prom is connected to sport1, data is clocked into the admc331 at a rate clkout/20. both pro- gram and data memory ram can be loaded from the srom or e 2 prom. after the boot load is complete, program execution begins at address 0x0030. this is where the first instruction of the user code should be placed. if boot loading from an e 2 prom is unsuccessful, the monitor code reconfigures sport1 as a uart and attempts to receive commands from an external device on this serial port. the monitor then waits for a byte to be received over sport1, locks onto the baud rate of the external device (autobaud fea- ture) and takes in a header word that tells it with what type of device it is communicating. there are six alternatives: a uart boot loader such as a motorola 68hc11sci port. a synchronous slave boot loader (the clock is external). a synchronous master boot loader (the admc331 provides the clock). a uart debugger interface. a synchronous master debugger interface. a synchronous slave debugger interface. with the debugger interface, the monitor enters an interactive mode in which it processes commands received from the exter- nal device. dsp control registers the dsp core has a system control register, syscntl, memory mapped at dm (0x3fff). sport0 is enabled when bit 12 is set, disabled when this bit is cleared. sport1 is enabled when bit 11 is set, disabled when this bit is cleared. sport1 is con- figured as a serial port when bit 10 is set, or as flags and inter- rupt lines when this bit is cleared. for proper operation of the admc331, all other bits in this register must be cleared (which is their default). the dsp core has a wait state control register, memwait, memory mapped at dm (0x3ffe). for proper operation of the admc331, this register must always contain the value 0x8000 (which is the default). the configuration of both the syscntl and memwait registers of the admc331 is shown at the end of the data sheet. three-phase pwm controller overview the pwm generator block of the admc331 is a flexible, pro- grammable, three-phase pwm waveform generator that can be programmed to generate the required switching patterns to drive a three-phase voltage source inverter for ac induction (acim), or permanent magnet synchronous (pmsm) or a switched or variable reluctance (srm) motor control. in addition, the pwm block contains special functions that considerably sim- plify the generation of the required pwm switching patterns for control of the electronically commutated motor (ecm) or brushless dc motor (bdcm). the pwm generator produces three pairs of pwm signals on the six pwm output pins (ah, al, bh, bl, ch and cl). the six pwm output signals consist of three high side drive signals (ah, bh and ch) and three low side drive signals (al, bl and cl). the polarity of the generated pwm signals may be programmed by the pwmpol pin, so that either active hi or active lo pwm patterns can be produced by the admc331. the switching frequency, dead time and minimum pulsewidths of the generated pwm patterns are programmable using respec- tively the pwmtm, pwmdt and pwmpd registers. in addi- tion, three duty cycle control registers (pwmcha, pwmchb and pwmchc) directly control the duty cycles of the three pair of pwm signals. when the pwmsr pin is pulled low, the pwm generator trans- forms the six pwm output signals into six waveforms for switched reluctance gate drive signals. the low side pwm signals from the three-phase timing unit assume permanently on states, independent of the value written to the duty-cycle registers. the duty cycles of the high side pwm signals from the timing unit are still determined by the three duty-cycle registers. each of the six pwm output signals can be enabled or disabled by separate output enable bits of the pwmseg register. in addition, three control bits of the pwmseg register permit crossover of the two signals of a pwm pair for easy control of ecm or bdcm. in crossover mode, the pwm signal destined for the high side switch is diverted to the complementary low side output and the signal destined for the low side switch is diverted to the corresponding high side output signal. in many applications, there is a need to provide an isolation barrier in the gate-drive circuits that turn on the power devices of the inverter. in general, there are two common isolation techniques, optical isolation using opto-couplers, and trans- former isolation using pulse transformers. the pwm controller of the admc331 permits mixing of the output pwm signals with a high frequency chopping signal to permit easy interface to such pulse transformers. the features of this gate-drive chop- ping mode can be controlled by the pwmgate register. there is an 8-bit value within the pwmgate register that directly con- trols the chopping frequency. in addition, high frequency chopping can be independently enabled for the high side and the low side outputs using separate control bits in the p wmgate register. the pwm generator is capable of operating in two distinct modes, single update mode or double update mode. in single update mode, the duty cycle values are programmable only once per pwm period, so that the resultant pwm patterns are sym- metrical about the midpoint of the pwm period. in the double update mode, a second updating of the pwm duty cycle values is implemented at the midpoint of the pwm period. in this mode, it is possible to produce asymmetrical pwm patterns, that produce lower harmonic distortion in three-phase pwm inverters. this technique also permits the closed loop controller to change the average voltage applied to the machine winding at a faster rate and so permits fast closed loop bandwidths to be achieved. the operating mode of the pwm block (single or double update mode) is selected by a control bit in modectrl register.
admc331 C13C rev. b the pwm generator of the admc331 also provides an output pulse on the pwmsync pin that is synchronized to the pwm switching frequency. in single update mode, a pwmsync pulse is produced at the start of each pwm period. in double update mode, an additional pwmsync pulse is produced at the midpoint of each pwm period. the width of the pwm- sync pulse is programmable through the pwmsyncwt register. the pwm signals produced by the admc331 can be shut-off in two different ways. firstly there is a dedicated asynchronous pwm shutdown pin, pwmtrip , that when brought lo, in- stantaneously places all six pwm outputs in the off state (as determined by the state of the pwmpol pin). this hardware shutdown mechanism is asynchronous so that the associated pwm disable circuitry does not go through any clocked logic, thereby ensuring correct pwm shutdown even in the event of a loss of dsp clock. in addition to the hardware shutdown fea- ture, the pwm system may be shutdown in software by writing to the pwmswt register. status information about the pwm system of the admc331 is available to the user in the sysstat register. in particular, the state of the pwmtrip , pwmpol and pwmsr pins is available, as well as a status bit that indicates whether operation is in the first half or the second half of the pwm period. a functional block diagram of the pwm controller is shown in figure 5. the generation of the six output pwm signals on pins ah to cl is controlled by four important blocks: the three-phase pwm timing unit, which is the core of the pwm controller, generates three pairs of complemented and dead time adjusted center based pwm signals. the switched reluctance control unit transforms the three- phase outputs into six pwm wave forms for switched reluc- tance gate drive signals. the output control unit allows the redirection of the out- puts of the three-phase timing unit for each channel to either the high side or the low side output. in addition, the output control unit allows individual enabling/disabling of each of the six pwm output signals. the gate drive unit provides the correct polarity output pwm signals based on the state of the pwmpol pin. the gate drive unit also permits the generation of the high fre- quency chopping frequency and its subsequent mixing with the pwm signals. the pwm controller is driven by a clock at the same frequency as the dsp instruction rate, clkout, and is capable of gener- ating two interrupts to the dsp core. one interrupt is gener- ated on the occurrence of a pwmsync pulse and the other is generated on the occurrence of any pwm shutdown action. three-phase timing unit the 16-bit three-phase timing unit is the core of the pwm controller and produces three pair of pulsewidth modulated signals with high resolution and minimal processor overhead. the outputs of this timing unit are active lo such that a low level is interpreted as a command to turn on the associated power device. there are four main configuration registers (pwmtm, pwmdt, pwmpd and pwmsyncwt) that determine the fundamental characteristics of the pwm outputs. in addition, the operating mode of the pwm (single or double update mode) is selected by bit 6 of the modectrl register. pwmtm (15 . . . 0) pwmdt (9 . . . 0) pwmpd (9 . . . 0) pwmsyncwt (7 . . . 0) modectrl (6) pwmseg pwmgate output control unit sync gate drive unit clk ah al bh bl ch cl clkout pwmtrip pwmsync switched reluctance control unit sr pwm duty cycle registers pwm configuration registers pol pwmpol pwmtrip to interrupt controller or three-phase pwm timing unit clk reset sync pwmsr pwmswt (0) pwmcha (15 . . . 0) pwmchb (15 . . . 0) pwmchc (15 . . . 0) pwmsync figure 5. overview of the pwm controller of the admc331
admc331 C14C rev. b these registers, in conjunction with the three 16-bit duty-cycle registers (pwmcha, pwmchb and pwmchc), control the output of the three-phase timing unit. pwm switching frequency, pwmtm register the pwm switching frequency is controlled by the 16-bit read/ write pwm period register, pwmtm. the fundamental timing unit of the pwm controller is t ck (dsp instruction rate). therefore, for a 26 mhz clkout, the fundamental time increment is 38.5 ns. the value written to the pwmtm regis- ter is effectively the number of t ck clock increments in half a pwm period. the required pwmtm value is a function of the desired pwm switching frequency (f pwm ) and is given by: pwmtm = f clkout 2 f pwm = f clkin f pwm therefore, the pwm switching period, t s , can be written as: t s = 2 pwmtm t ck for example, for a 26 mhz clkout and a desired pwm switching frequency of 10 khz (t s = 100 s), the correct value to load into the pwmtm register is: pwmtm = 26 10 6 2 10 10 3 = 1300 the largest value that can be written to the 16-bit pwmtm register is 0xffff = 65,535 which corresponds to a minimum pwm switching frequency of: f pwm ,min = 26 10 6 2 65,535 = 198.4 hz pwm switching dead time, pwmdt register the second important parameter that must be set up in the initial configuration of the pwm block is the switching dead time. that is a short delay time introduced between turning off one pwm signal (ah) and turning on the complementary sig- nal, al. this short time delay is introduced to permit the power switch being turned off (ah in this case) to completely recover its blocking capability before the complementary switch is turned on. this time delay prevents a potentially destructive short-circuit condition from developing across the dc link ca- pacitor of a typical voltage source inverter. the dead time is controlled by the 10-bit, read/write pwmdt register. there is only one dead time register that controls the dead time inserted into the three pairs of pwm output signals. the dead time, t d , is related to the value in the pwmdt regis- ter by: t d = pwmtm 2 t ck therefore, a pwmdt value of 0x00a (= 10), introduces a 769.2 ns delay between the turn-off on any pwm signal (ah) and the turn-on of its complementary signal (al). the amount of the dead time can therefore be programmed in increments of 2t ck (or 76.92 ns for a 26 mhz clkout). the pwmdt register is a 10-bit register so that its maximum value is 0x3ff (=1023) corresponding to a maximum programmed dead time of: t d , max = 1023 2 t ck = 1023 2 38.46 10 9 = 78.69 s for a clkout rate of 26 mhz. obviously, the deadtime can be programmed to be zero by writing 0 to the pwmdt register. pwm operating mode, modectrl and sysstat registers the pwm controller of the admc331 can operate in two distinct modes: single update mode and double update mode. the operating mode of the pwm controller is determined by the state of bit 6 of the modectrl register. if this bit is cleared, the pwm operates in the single update mode. setting bit 6 places the pwm in the double update mode. by default, following either a peripheral reset or power on, bit 6 of the modectrl register is cleared so that the default operating mode is in single update mode. in single update mode, a single pwmsync pulse is produced in each pwm period. the rising edge of this signal marks the start of a new pwm cycle and is used to latch new values from the pwm configuration registers (pwmtm, pwmdt, pwmpd and pwmsyncwt) and the pwm duty-cycle registers (pwmcha, pwmchb and pwmchc) into the three-phase timing unit. in addition, the pwmseg register is also latched into the output control unit on the rising edge of the pwmsync pulse. in effect, this means that the characteristics and resultant duty cycles of the pwm signals can be updated only once per pwm period at the start of each cycle. the result is that pwm patterns that are symmetrical about the midpoint of the switch- ing period are produced. in double update mode, there is an additional pwmsync pulse produced at the midpoint of each pwm period. the rising edge of this new pwmsync pulse is again used to latch new values of the pwm configuration registers, duty-cycle registers and the pwmseg register. as a result it is possible to alter both the characteristics (switching frequency, dead time, minimum pulsewidth and pwmsync pulsewidth) as well as the ou tput duty cycles at the midpoint of each pwm cycle. consequently, it is possible to produce pwm switching patterns that are no longer symmetrical about the midpoint of the period (asymmetrical pwm patterns). in the double update mode, it may be necessary to know whether operation at any point in time is in either the first half or the second half of the pwm cycle. this information is provided by bit 3 of the sysstat register, which is cleared during opera- tion in the first half of each pwm period (between the rising edge of the original pwmsync pulse and the rising edge of the new pwmsync pulse introduced in double update mode). bit 3 of the sysstat register is set during operation in the second half of each pwm period. this status bit allows the user to make a determination of the particular half-cycle during implementation of the pwmsync interrupt service routine, if required. the advantage of the double update mode is that lower har- monic voltages can be produced by the pwm process and faster control bandwidths are possible. however, for a given pwm switching frequency, the pwmsync pulses occur at twice the rate in the double update mode. since new duty cycle values must be computed in each pwmsync interrupt service rou- tine, there is a larger computational burden on the dsp in the double update mode.
admc331 C15C rev. b width of the pwmsync pulse, pwmsyncwt register the pwm controller of the admc331 produces an output pwm synchronization pulse at a rate equal to the pwm switch- ing frequency in single update mode and at twice the pwm frequency in the double update mode. this pulse is available for external use at the pwmsync pin. the width of this pwmsync pulse is programmable by the 8-bit read/write pwmsyncwt register. the width of the pwmsync pulse, t pwmsync , is given by: t pwmsync = t ck ( pwmsyncwt + 1) so that the width of the pulse is programmable from t ck to 256 t ck (corresponding to 38.5 ns to 9.84 s for a clkout rate of 26 mhz). following a reset, the pwmsyncwt register con- tains 0x27 (= 39) so that the default pwmsync width is 1.54 s, again for a 26 mhz clkout. pwm duty cycles, pwmcha, pwmchb, pwmchc registers the duty cycles of the six pwm output signals on pins ah to cl are controlled by the three 16-bit read/write duty-cycle registers, pwmcha, pwmchb, and pwmchc. the integer value in the register pwmcha controls the duty cycle of the signals on ah and al, in pwmchb, controls the duty cycle of the signals on bh and bl and in pwmchc, controls the duty cycle of the signals on ch and cl. the duty-cycle registers are programmed in integer counts of the fundamental time unit, t ck , and define the desired on-time of the high side pwm signal produced by the three-phase timing unit over half the pwm period. the switching signals produced by the three-phase timing unit are also adjusted to incorporate the programmed dead time value in the pwmdt register. the three-phase timing unit produces active lo signals so that a lo level corre- sponds to a command to turn on the associated power device. a typical pair of pwm outputs (in this case for ah and al) from the timing unit are shown in figure 6 for operation in single update mode. all illustrated time values indicate the integer value in the associated register and can be converted to time simply by multiplying by the fundamental time increment, t ck . firstly, it is noted that the switching patterns are perfectly symmetrical about the midpoint of the switching period in this single update mode since the same values of pwmcha, pwmtm and pwmdt are used to define the signals in both half cycles of the period. it can be seen how the programmed duty cycles are adjusted to incorporate the desired dead time into the resultant pair of pwm signals. clearly, the dead time is incorporated by moving the switching instants of both pwm signals (ah and al) away from the instant set by the pwmcha register. both switching edges are moved by an equal amount (pwmdt t ck ) to preserve the symmetrical output patterns. also shown is the pwmsync pulse whose width is set by the pwmsyncwt register and bit 3 of the sysstat register, which indicates whether operation is in the first or second half cycle of the pwm period. obviously negative values of t ah and t al are not permitted and the minimum permissible value is zero, corresponding to a 0% duty cycle. in a similar fashion, the maximum value is t s , corresponding to a 100% duty cycle. pwmcha 2 pwmdt pwmsyncwt + 1 pwmcha pwmtm pwmtm ah al pwmsync sysstat (3) 2 pwmdt figure 6. typical pwm outputs of three-phase timing unit in single update mode (active lo waveforms) the resultant on-times of the pwm signals in figure 6 may be written as: t ah = 2 ( pwmcha pwmdt ) t ck t al = 2 (pwmtm pwmcha pwmdt) t ck and the corresponding duty cycles are: d ah = t ah t s = pwmcha pwmdt pwmtm d al = t al t s = pwmtm pwmcha pwmdt pwmtm the output signals from the timing unit for operation in double update mode are shown in figure 7. this illustrates a com- pletely general case where the switching frequency, dead time and duty cycle are all changed in the second half of the pwm period. of course, the same value for any or all of these quanti- ties could be used in both halves of the pwm cycle. however, it can be seen that there is no guarantee that symmetrical pwm signal will be produced by the timing unit in this double update mode. additionally, it is seen that the dead time is inserted into the pwm signals in the same way as in the single update mode. pwmcha 2 pwmsyncwt 2 + 1 pwmcha 1 pwmtm 1 pwmtm 2 pwmsyncwt 1 + 1 ah al pwmsync sysstat (3) 2 pwmdt 1 2 pwmdt 2 figure 7. typical pwm outputs of three-phase timing unit in double update mode (active lo waveforms) in general, the on-times of the pwm signals in double update mode can be defined as: t ah = pwmcha 1 + pwmcha 2 ? pwmdt 1 ? pwmdt 2 () t ck t al = ( pwmtm 1 + pwmtm 2 pwmcha 1 pwmcha 2 pwmdt 1 pwmdt 2 ) t clk
admc331 C16C rev. b where the subscript 1 refers to the value of that register during the first half cycle and the subscript 2 refers to the value during the second half cycle. the corresponding duty cycles are: d al = t ah t s = ( pwmcha 1 + pwmcha 2 pwmdt 1 pwmdt 2 ) ( pwmtm 1 + pwmtm 2 ) d al = t al t s = ( pwmtm 1 + pwmtm 2 pwmcha 1 pwmcha 2 pwmdt 1 pwmdt 2 ) ( pwmtm 1 + pwmtm 2 ) since for the completely general case in double update mode, the switching period is given by: t s = ( pwmtm 1 + pwmtm 2 ) t ck again, the values of t ah and t al are constrained to lie between zero and t s . similar pwm signals to those illustrated in figure 6 and fig- ure 7 can be produced on the bh, bl, ch and cl outputs by programming the pwmchb and pwmchc registers in a man- ner i dentical to that described for pwmcha. the pwm controller does not produce any pwm outputs until all of the pwmtm, pwmcha, pwmchb and pwmchc registers have been written to at least once. once these registers have been written, internal counting of the timers in the three- phase timing unit is enabled. effective pwm resolution in single update mode, the same value of pwmcha, pwm- chb and pwmchc are used to define the on-times in both half cycles of the pwm period. as a result, the effective resolu- tion of the pwm generation process is 2 t ck (or 76.9 ns for a 26 mhz clkout) since incrementing one of the duty-cycle registers by 1 changes the resultant on-time of the associated pwm signals by t ck in each half period (or 2 t ck for the full period). in double update mode, improved resolution is possible since different values of the duty cycles registers are used to define the on-times in both the first and second halves of the pwm period. as a result, it is possible to adjust the on-time over the whole period in increments of t ck . this corresponds to an effective pwm resolution of t ck in double update mode (or 38.5 ns for a 26 mhz clkout). the achievable pwm switching frequency at a given pwm resolution is tabulated in table v. table v. achievable pwm resolution in single and double update modes resolution single update mode double update mode (bit) pwm frequency (khz) pwm frequency (khz) 8 50.7 101.5 9 25.4 50.7 10 12.7 25.4 11 6.3 12.7 12 3.2 6.3 minimum pulsewidth, pwmpd register in many power converter switching applications, it is desirable to eliminate pwm switching signals below a certain width. it takes a certain finite time to both turn on and turn off modern power semiconductor devices. therefore, if the width of any of the pwm signals goes below some minimum value, it may be desirable to completely eliminate the pwm switching for that particular cycle. the allowable minimum on-time for any of the six pwm out- puts over half a pwm period that can be produced by the pwm controller may be programmed using the 10-bit read/write pwmpd register. the minimum on-time is programmed in increments of t ck so that the minimum on-time that will be produced over any half pwm period, t min , is related to the value in the pwmpd register by: t min = pwmpd t ck so that a pwmpd value of 0x002 defines a permissible mini- mum on-time of 76.9 ns for a 26 mhz clkout. in each half cycle of the pwm, the timing unit checks the on- time of each of the six pwm signals. if any of the times are found to be less than the value specified by the pwmpd regis- ter, the corresponding pwm signal is turned off for the entire half period and its complementary signal is turned completely on. consider the example where pwmtm = 200, pwmcha = 5, pwmdt = 3, pwmpd = 10 with a clkout of 26 mhz and operation in single update mode. in this case, the pwm switching frequency is 65 khz and the dead time is 230 ns. the permissible on-time of any pwm signal over one half of any period is 384.6 ns. clearly, for this example, the dead time adjusted on-time of the ah signal over half a pwm period is (5 3) 38.5 ns = 77 ns. this is less than the permis- sible value, so the timing unit will output a completely off (0% duty cycle) signal on ah. additionally, the al signal will be turned on for the entire half period (100% duty cycle). switched reluctance mode the pwm block of the admc331 contains a switched reluc- tance mode that is controlled by the state of the pwmsr pin. the switched reluctance (sr) mode is enabled by connecting the pwmsr pin to gnd. in this sr mode, the low side pwm signals from the three-phase timing unit assume permanently on states, independent of the value written to the duty-cycle registers. the duty cycles of the high side pwm signals from the timing unit are still determined by the three duty-cycle regis- ters. using the crossover feature of the output control unit, it is possible to divert the permanently on pwm signals to either the high side or the low side outputs. this mode is necessary because in the typical power converter configuration for switched or variable reluctance motors, the motor winding is connected between the two power switches of a given inverter leg. there- fore, in order to build up current in the motor winding, it is necessary to turn on both switches at the same time. typical active lo pwm signals during operation in sr mode are shown in figure 8 for operation in double update mode. it is clear that the three low side signals (al, bl and cl) are permanently on and the three high side signals are modulated so that the corre- sponding high side power switches are switched between the on and off states.
admc331 C17C rev. b pwmtm 1 ah pwmchc 1 pwmchc 2 pwmtm 2 pwmchb 2 pwmchb 1 pwmcha 1 pwmcha 2 al bh bl ch cl figure 8. active lo pwm signals in sr mode (pwmpol = pwmsr = gnd) for admc331 in double update mode. the signals from the three-phase unit are not crossed over (pwmseg = 0) and the dead time is zero (pwmdt = 0). the sr mode can only be enabled by connecting the pwmsr pin to gnd. there is no software means by which this mode can be enabled. there is an internal pull-up resistor on the pwmsr pin so that if this pin is left unconnected or becomes disconnected the sr mode is disabled. of course, the sr mode is disabled when the pwmsr pin is tied to v dd . the state of the pwmsr pin may be read from bit 4 of the sysstat register. output control unit, pwmseg register the operation of the output control unit is controlled by the 9-bit read/write pwmseg register that controls two distinct features that are directly useful in the control of ecm or bdcm. the pwmseg register contains three crossover bits, one for each pair of pwm outputs. setting bit 8 of the pwmseg register enables the crossover mode for the ah/al pair of pwm signals; setting bit 7 enables crossover on the bh/bl pair of pwm signals; setting bit 6 enables crossover on the ch/cl pair of pwm signals. if crossover mode is enabled for any pair of pwm signals, the high side pwm signal from the timing unit (i.e. ah) is diverted to the associated low side output of the output control unit so that the signal will ultimately appear at the al pin. of course, the corresponding low side output of the timing unit is also diverted to the complementary high side output of the output control unit so that the signal appears at the ah pin. following a reset, the three crossover bits are cleared so that the crossover mode is disabled on all three pairs of pwm signals. the pwmseg register also contains six bits (bits 0 to 5) that can be used to individually enable or disable each of the six pwm outputs. the pwm signal of the al pin is enabled by setting bit 5 of the pwmseg register while bit 4 controls ah, bit 3 controls bl, bit 2 controls bh, bit 1 controls cl and bit 0 controls the ch output. if the associated bit of the pwmseg register is set, then the corresponding pwm output is disabled irrespective of the value of the corresponding duty cycle register. this pwm output signal will remain in the off state as long as the corresponding enable/disable bit of the pwmseg register is set. the implementation of this output enable function is implemented after the crossover function. following a reset, all six enable bits of the pwmseg register are cleared so that all pwm outputs are enabled by default. in a manner identical to the duty-cycle registers, the pwmseg is latched on the rising edge of the pwmsync signal so that the changes to this register only become effective at the start of each pwm cycle in single update mode. in double update mode, the pwmseg register can also be updated at the midpoint of the pwm cycle. in the control of an ecm, only two inverter legs are switched at any time and often the high side device in one leg must be switched on at the same time as the low side driver in a second leg. therefore, by programming identical duty cycles values for two pwm channels (i.e., pwmcha = pwmchb) and setting bit 7 of the pwmseg register to crossover the bh/bl pair if pwm signals, it is possible to turn on the high side switch of phase a and the low side switch of phase b at the same time. in the control of ecm, it is usual that the third inverter leg (phase c in this example) be permanently disabled for a number of pwm cycles. this function is implemented by disabling both the ch and cl pwm outputs by setting bits 0 and 1 of the pwmseg register. this situation is illustrated in figure 9 where it can be seen that both the ah and bl signals are identi- cal, since pwmcha = pwmchb and the crossover bit for phase b is set. in addition, the other four signals (al, bh, ch and cl) have been disabled by setting the appropriate enable/ disable bits of the pwmseg register. for the situation illus- trated in figure 9, the appropriate value for the pwmseg register is 0x00a7. in normal ecm operation, each inverter leg is disabled for certain periods of time, so that the pwmseg register is ch anged based on the position of the rotor shaft (motor commutation). ah al bh bl ch cl pwmtm pwmtm pwmcha = pwmchb pwmcha = pwmchb 2 pwmdt 2 pwmdt figure 9. example active lo pwm signals suitable for ecm control, pwmcha = pwmchb, crossover bh/bl pair and disable al, bh, ch and cl outputs. operation is in single update mode. gate drive unit, pwmgate register the gate drive unit of the pwm controller adds features that simplify the design of isolated gate drive circuits for pwm inverters. if a transformer-coupled power device gate driver amplifier is used, the active pwm signals must be chopped at a high frequency. the 10-bit read/write pwmgate register allows the programming of this high frequency chopping mode. the chopped active pwm signals may be required for the high side drivers only, for the low side drivers only or for both the high side and low side switches. therefore, indepen- dent control of this mode for both high and low side switches is
admc331 C18C rev. b included with two separate control bits in the pwmgate register. typical pwm output signals with high frequency chopping enabled on both high side and low side signals are shown in figure 10. chopping of the high side pwm outputs (ah, bh and ch) is enabled by setting bit 8 of the pwmgate register. chopping of the low side pwm outputs (al, bl and cl) is enabled by setting bit 9 of the pwmgate register. the high frequency chopping frequency is controlled by the 8-bit word (gdclk) placed in bits 0 to 7 of the pwmgate register. the period of this high frequency carrier is: t chop = [4 ( gdclk + 1)] t ck f chop = f clkout [4 ( gdclk + 1)] the gdclk value may range from 0 to 255, corresponding to a programmable chopping frequency rate from 25.39 khz to 6.5 mhz for a 26 mhz clkout rate. the gate drive features must be programmed before operation of the pwm controller and typically are not changed during normal operation of the pwm controller. following a reset, all bits of the pwmgate register are cleared so that high frequency chopping is disabled, by default. pwmtm pwmtm [4 (gdclk+1) t ck ] 2 pwmdt 2 pwmdt pwmcha pwmcha figure 10. typical active lo pwm signals with high fre- quency gate chopping enabled on both high side and low side switches pwm polarity control, pwmpol pin the polarity of the pwm signals produced at the output pins ah to cl may be selected in hardware by the pwmpol pin. connecting the pwmpol pin to gnd selects active lo pwm outputs, such that a lo level is interpreted as a command to turn on the associated power device. conversely, connecting v dd to pwmpol pin selects active hi pwm and the associ- ated power devices are turned on by a hi level at the pwm outputs. there is an internal pull-up on the pwmpol pin, so that if this pin becomes disconnected (or is not connected), active hi pwm will be produced. the level on the pwmpol pin may be read from bit 2 of the sysstat register, where a zero indicated a measure lo level at the pwmpol pin. pwm shutdown in the event of external fault conditions, it is essential that the pwm system be instantaneously shut down in a safe fashion. a falling edge on the pwmtrip pin provides an instantaneous, asynchronous (independent of the dsp clock) shutdown of the pwm controller. all six pwm outputs are placed in the off state (as defined by the pwmpol pin). in addition, the pwm- sync pulse is disabled and the associated interrupt is stopped. the pwmtrip pin has an internal pull-down resistor so that if the pin be comes disconnected the pwm will be disabled. the state of the pwmtrip pin can be read from bit 0 of the sysstat register. in addition, it is possible to initiate a pwm shutdown in soft- ware by writing to the 1-bit read/write pwmswt register. the act of writing to this register generates a pwm shutdown com- mand in a manner identical to the pwmtrip pin. it does not matter which value is written to the pwmswt register. how- ever, following a pwm shutdown, it is possible to read the pwmswt register to determine if the shutdown was generated by hardware or software. reading the pwmswt register auto- matically clears its contents. on the occurrence of a pwm shutdown command (either from the pwmtrip pin or the pwmswt register), a pwmtrip interrupt will be generated. in addition, internal timing of the three-phase timing unit of the pwm controller is stopped. fol- lowing a pwm shutdown, the pwm can only be re-enabled (in a pwmtrip interrupt service routine, for example) by writing to all of the pwmtm, pwmcha, pwmchb and pwmchc registers. provided the external fault has been cleared and the pwmtrip has returned to a hi level, internal timing of the three-phase timing unit resumes and new duty cycle values are latched on the next pwmsync boundary. pwm registers the configuration of the pwm registers is described at the end of the data sheet. adc overview the analog input block of the admc331 is a 7-channel single slope analog data acquisition system with 12-bit resolution. data conversion is performed by timing the crossover between the analog input and sawtooth reference ramp. a simple voltage comparator detects the crossover and latches the timed counter value into a channel-specific output register the adc system is comprised of seven input channels to the adc of which three (v1, v2, v3) have dedicated comparators. the remaining four channels (vaux0, vaux1, vaux2, vaux3) are multiplexed into the fourth comparator and are selected using the adcmux0 and adcmux1 bits of the modectrl regis- ter (table vi). this allows four conversions to be performed by the adc between successive pwmsync pulses. table vi. adc auxiliary channel selection modectrl (1) modectrl (0) select adcmux1 adcmux0 vaux0 0 0 vaux1 0 1 vaux2 1 0 vaux3 1 1 analog block the operation of the adc block may be explained by reference to figures 11 and 12. the reference ramp is tied to one input of each of the four comparators. this reference ramp is generated by charging an external timing capacitor with a constant current source. the timing capacitor is connected between pins capin and sgnd. the capacitor voltage is reset at the start of each pwmsync pulse, which by default is held high for 40 clkout cycles (t crst = 1.54 s for a 26 mhz clkout). on the fall- ing edge of pwmsync, the capacitor begins to charge at a rate
admc331 C19C rev. b determined by the capacitor and the current source values. an internal current source is made available for connection to the external timing capacitor on the iconst pin. an external current source could also be used, if required. the four input comparators of the adc block continuously compare the values of the four analog inputs with the capacitor voltage. each com- parator output will go high when the capacitor voltage exceeds the respective analog input voltage. adc timer block the adc timer block consists of a 12-bit counter clocked at a rate determined by the adccnt bit in the modectrl register. if adccnt is 0, the counter is clocked at twice the clkout period, or if adccnt is 1, the counter is clocked at the clkout period. t hus at the maximum clkout frequency of 26 mhz, this gives a timer resolution of 76.9 ns when adccnt is 0, and 38.5 ns when adccnt is 1. the counter is reset during the high pwmsync pulse so that the counter commences at the beginning of the reference voltage ramp. when the output of a given comparator goes high, the counter value is latched into the appropriate 12-bit adc regis- ter. there are four pair of adc registers (adc1, adc2, adc3 and adcaux) corresponding to each of the four com- parators. each comparator s register pair is organized as master/ slave or master/shadow. at the end of the reference voltage ramp, which is prior to the next pwmsync, all four master registers have been loaded with the new conversion count. at the rising edge of the pwmsync, the registered conversion count for each chan- nel is loaded into the dsp readable shadow registers, adc1, adc2, adc3, and adcaux. the controller will then read these shadow registers containing the previous pwm period conversion count, while internally the master registers will be loaded with the current pwm period conversion count. the first set of values loaded into the output registers after the first pwmsync interrupt will be invalid since the latched value is indeterminate. also, if the input analog voltage exceeds the peak capacitor ramp voltage, the comparator output will be permanently low and a 0xfff0 code will be produced. this indicates an input overvoltage condition. vref iconst capin c sgnd vaux0 vaux1 vaux2 vaux3 adc timer block adc2 adcaux admux0 admux1 4-1 mux v1 pwmsync adc registers clkout adc1 adc3 modectrl (7) v2 v3 figure 11. adc overview v1 pwmsync v vil comparator output t v c v cmax t crst t vil t pwm ?t crst figure 12. analog input block operation adc resolution because the operation of the adc is intrinsically linked to the pwm block, the effective resolution of the adc is a function of the pwm switching frequency. the effective adc resolution is determined by the rate at which the counter timer is clocked, which is selectable by the adccnt bit 7 in modectrl register. for a clkout period of t ck and a pwm period of t pwm , the maximum count of the adc is given by: max count = min (4095, (t pwm t crst )/2 t ck modectrl bit 7 = 0 max count = min (4095, (t pwm t crst )/t ck modectrl bit 7 = 1 for an assumed clkout frequency of 26 mhz and pwm- sync pulsewidth of 1.54 s, the effective resolution of the adc block is tabulated for various pwm switching frequencies in table vii. table vii. adc resolution examples pwm modectrl[7] = 0 modectrl[7] = 1 freq. max effective max effective (khz) count resolution count resolution 2.5 4095 12 4095 12 4 3230 >11 4095 12 8 1605 >10 3210 >11 18 702 >9 1404 >10 24 521 >9 1043 >10 external timing capacitor in order to maximize the useful input voltage range and effective resolution of the adc, it is necessary to carefully select the value of the external timing capacitor. for a given capacitance value, c nom , the peak ramp voltage is given by: v c max = i const ( t pwm t crst ) c nom where i const is the nominal current source value of 13.5 a and t crst is the pwmsync pulsewidth. in selecting the capacitor value, however, it is necessary to take into account the tolerance of the capacitor and the variation of the current source value.
admc331 C20C rev. b to ensure that the full input range of the adc is utilized, it is necessary to select the capacitor so that at the maximum capaci- tance value and the minimum current source output, the ramp voltage will charge to at least 3.5 v. as a result, assuming 10% variations in both the capacitance and current source, the nominal capacitance value required at a given pwm period is: c nom = (0.9 i const )( t pwm t crst ) (1.1) (3.5) the largest standard value capacitor that is less than this calcu- lated value is chosen. table viii shows the appropriate standard capacitor value to use for various pwm switching frequencies assuming 10% variations in both the current source and ca- pacitor tolerances. if required, more precise control of the ramp voltage is possible by using higher precision capacitor compo- nents, an external current source and/or series or parallel timing capacitor combinations. table viii. timing capacitor selection pwm frequency pwm frequency timing (khz) (khz) capacitor modectrl[6] = 0 modectrl[6] = 1 (pf) 2.1 2.7 4.2 5.2 1500 2.7 3.2 5.2 6.3 1200 3.2 3.9 6.3 7.7 1000 3.9 4.7 7.7 9.2 820 4.7 5.6 9.2 11.2 680 5.6 6.7 11.2 13.3 560 6.7 8.0 13.3 16.0 470 8.0 9.5 16.0 18.8 390 9.5 11.5 18.8 23.0 330 11.5 14.1 23.0 28.1 270 14.1 17.1 28.1 34.1 220 17.1 20.4 34.1 40.8 180 20.4 25.3 40.8 50.6 150 25.3 30.1 50.6 60.2 120 adc registers the configuration of all registers of the adc system is shown at the end of the data sheet. auxiliary pwm timers overview the admc331 provides two variable-frequency, variable duty cycle, 8-bit, auxiliary pwm outputs that are available at the aux1 and aux0 pins. these auxiliary pwm outputs can be used to provide switching signals to other circuits in a typical motor control system such as power factor corrected front-end converters or other switching power converters. alternatively, by addition of a suitable filter network, the auxiliary pwm out- put signals can be used as simple single-bit digital-to-analog converters. the auxiliary pwm system of the admc331 can operate in two different modes, independent mode or offset mode. the operating mode of the auxiliary pwm system is controlled by bit 8 of the modectrl register. setting bit 8 of the modectrl register places the auxiliary pwm system in the independent mode. in this mode, the two auxiliary pwm gen- erators are completely independent and separate switching fre- quencies and duty cycles may be programmed for each auxiliary pwm output. in this mode, the 8-bit auxtm0 register sets the switching frequency of the signal at the aux0 output pin. similarly, the 8-bit auxtm1 register sets the switching of the signal at the aux1 pin. the fundamental time increment for the auxiliary pwm outputs is twice the dsp instruction rate (or 2 t ck ) so that the corresponding switching periods are given by: t aux 0 = 2 ( auxtm 0 + 1) t ck t aux 1 = 2 ( auxtm 1 + 1) t ck since the values in both auxtm0 and auxtm1 can range from 0 to 0xff, the achievable switching frequency of the auxil- iary pwm signals may range from 50.8 khz to 13 mhz for a clkout frequency of 26 mhz. the on-time of the two auxiliary pwm signals is programmed by the two 8-bit auxch0 and auxch1 registers, according to: t on , aux 0 = 2 ( auxch 0) t ck t on , aux 1 = 2 ( auxch 1) t ck so that output duty cycles from 0% to 100% are possible. duty cycles of 100% are produced if the on-time value exceeds the period value. typical auxiliary pwm waveforms in independent mode are shown in figure 13(a). when bit 8 of the modectrl register is cleared, the auxiliary pwm channels are placed in offset mode. in offset mode, the switching frequency of the two signals on the aux0 and aux1 pins are identical and controlled by auxtm0 in a manner similar to that previously described for independent mode. in addition, the on times of both the aux0 and aux1 signals are controlled by the auxch0 and auxch1 registers as before. however, in this mode the auxtm1 register defines the offset time from the rising edge of the signal on the aux0 pin to that on the aux1 pin according to: t offset = 2 ( auxtm 1 + 1) t ck for correct operation in this mode, the value written to the auxtm1 register must be less than the value written to the auxtm0 register. typical auxiliary pwm waveforms in offset mode are shown in figure 13(b). again, duty cycles from 0% to 100% are possible in this mode. in both operating modes, the resolution of the auxiliary pwm system is 8-bit only at the minimum switching frequency (auxtm0 = auxtm1 = 255 in independent mode, auxtm0 = 255 in offset mode). obviously as the switching frequency is increased the resolution is reduced. values can be written to the auxiliary pwm registers at any time. however, new duty cycle values written to the auxch0 and auxch1 registers only become effective at the start of the next cycle. writing to the auxtm0 or auxtm1 registers cause the internal timers to be reset to 0 and new pwm cycles begin. by default, following power on or a reset, bit 8 of the modectrl register is cleared so that offset mode is enabled. in addition, the registers auxtm0 and auxtm1 default to 0xff, corresponding to minimum switching frequency and zero offset. in addition, the on-time registers auxch0 and auxch1 default to 0x00.
admc331 C21C rev. b aux0 aux1 aux0 aux1 2 (auxtm1 + 1) 2 (auxtm0 + 1) 2 auxch0 2 (auxtm0 + 1) 2 auxch1 2 (auxtm0 + 1) 2 (auxtm1 + 1) (a) (b) 2 auxch1 2 auxch0 auxch1 figure 13. typical auxiliary pwm signals in (a) independent mode and (b) offset mode (all times in increments of t ck ) auxiliary pwm interface, registers and pins the registers of the auxiliary pwm system are summarized at the end of the data sheet. pwm dac equation the pwm output can be filtered in order to produce a low frequency analog signal between 0 v to 4.98 v dc. for example, a 2-pole filter with a 1.2 khz cutoff frequency will sufficiently attenuate the pwm carrier. figure 14 shows how the filter would be applied. c1 c2 r1 r2 r1 = r2 = 13k c1 = c2 = 10nf pwmdac figure 14. auxiliary pwm output filter watchdog timer the admc331 incorporates a watchdog timer that can perform a full reset of the dsp and motor control peripherals in the event of software error. the watchdog timer is enabled by writ- ing a timeout value to the 16-bit wdtimer register. the timeout value represents the number of clkin cycles required for the watchdog timer to count down to zero. when the watchdog timer reaches zero, a full dsp core and motor control peripheral reset is performed. in addition, bit 1 of the sysstat register is set so that after a watchdog reset the admc331 can determine that the reset was due to the timeout of the watchdog timer and not an external reset. follow ing a watchdog reset, bit 1 of the sysstat register may be cleared by writing zero to the wdtimer register. this clears the status bit but does not enable the watchdog timer. on reset, the watchdog timer is disabled and is only enabled when the first timeout value is written to the wdtimer regis ter. to prevent the watchdog timer from timing out, the user must write to the wdtimer register at regular intervals (shorter than the programmed wdtimer period value). on all but the first write to wdtimer, the particular value written to the register is unimportant since writing to wdtimer simply reloads the first value written to this register. the wdtimer register is memory mapped to data memory at location 0x2018. programmable digital input/output the admc331 has 24 programmable digital i/o (pio) pins: pio0 pio23. each pin can be individually configurable as either an input or an output. input pins can also be used to generate interrupts. each pio pin includes an internal pull- down resistor. the pio pins are configured as input or output by setting the appropriate bits in the piodir0, piodir1 and piodir2 registers. the read/write registers piodata0, piodata1 and piodata2 are used to set the state of an output pin or read the state of an input pin. writing to piodata0, piodata1 and piodata2 affects only the pins configured as outputs. the default state, after an admc331 reset, is that all pios are config- ured as inputs. any pin can be configured as an independent edge-triggered interrupt source. the pin must first be configured as an input and then the appropriate bit must be set in the piointen0, or piointen1 or piointen2 registers. a peripheral interrupt is generated when the input level changes on any pio pin con- figured as an interrupt source. a pio interrupt sets the appro- priate bit in the pioflag0, or pioflag1 or pioflag2 registers. the dsp peripheral interrupt service routine (isr) must read the pioflag0, pioflag1 and pioflag2 regis- ters to determine which pio pin was the source of the pio interrupt. reading the pioflag0, pioflag1 and pioflag2 registers will clear them. pio registers the configuration of all registers of the pio system is shown at the end of the data sheet. interrupt control the admc331 can respond to 34 different interrupt sources with minimal overhead. eight of these interrupts are internal dsp core interrupts and twenty six are from the motor control peripherals. the eight dsp core interrupts are sport0 re- ceive and transmit, sport1 receive (or irq0 ) and transmit (or irq1 ), the internal timer and two software interrupts. the motor control interrupts are the 24 peripheral i/os and two from the pwm (pwmsync pulse and pwmtrip). all mo- tor control interrupts are multiplexed into the dsp core via the peripheral irq2 interrupt. they are also internally prioritized and individually maskable. the start address in the interrupt vector table for the admc331 interrupt sources is shown in table viii. the interrupts are listed from high priority to the lowest priority. the pwmsync interrupt is triggered by a low-to-high transi- tion on the pwmsync pulse. the pwmtrip interrupt is triggered on a high-to-low transition on the pwmtrip pin. a pio interrupt is detected on any change of state (high-to-low or low-to-high) on the pio lines.
admc331 C22C rev. b the entire interrupt control system of the admc331 is config- ured and controlled by the ifc, imask and icntl registers of the dsp core and the irqflag register for the pwmsync and pwmtrip interrupts and pioflag0, pioflag1 and pioflag2 registers for the pio interrupts. table ix. interrupt vector addresses interrupt vector interrupt source address reset 0x0000 (reserved) pwmtrip 0x002c (highest priority) peripheral interrupt ( irq2 ) 0x0004 pwmsync 0x000c pio 0x0008 sport0 transmit 0x0010 sport0 receive 0x0014 software interrupt 1 0x0018 software interrupt 0 0x001c sport1 transmit interrupt or irq1 0x0020 sport1 receive interrupt or irq0 0x0024 timer 0x0028 (lowest priority) interrupt masking interrupt masking (or disabling) is controlled by the imask register of the dsp core. this register contains individual bits that must be set to enable the various interrupt sources. if any peripheral interrupt is to be enabled, the irq2 interrupt enable bit (bit 9) of the imask register must be set. the configuration of the imask register of the admc331 is shown at the end of the data sheet. interrupt configuration the ifc and icntl registers of the dsp core control and configure the interrupt controller of the dsp core. the ifc register is a 16-bit register that may be used to force and/or clear any of the eight dsp interrupts. bits 0 to 7 of the ifc register may be used to clear the dsp interrupts while bits 8 to 15 can be used to force a corresponding interrupt. writing to bits 11 and 12 in ifc is the only way to create the two software interrupts. the icntl register is used to configure the sensitivity (edge- or level-) of the irq0 , irq1 and irq2 interrupts and to enable/ disable interrupt nesting. setting bit 0 of icntl configures the irq0 as edge-sensitive, while clearing the bit configures it for level-sensitive. bit 1 is used to configure the irq1 interrupt and bit 2 is used to configure the irq2 interrupt. it is recom- mended that the irq2 interrupt always be configured for level- sensitive as this ensures that no peripheral interrupts are lost. setting bit 4 of the icntl register enables interrupt nesting. the configuration of both ifc and icntl registers is shown at the end of the data sheet. interrupt operation following a reset, the rom code monitor of the admc331 copies a default interrupt vector table into program memory ram from address 0x0000 to 0x002f. since each interrupt source has a dedicated four-word space in this vector table, it is possible to code short interrupt service routines (isr) in place. alternatively, it may be required to insert a jump instruction to the appropriate start address of the interrupt service routine if more memory is required for the isr. on the occurrence of an interrupt, the program sequencer en- sures that there is no latency (beyond synchronization delay) when processing unmasked interrupts. in the case of the timer, sport0, sport1 and software interrupts, the interrupt con- troller automatically jumps to the appropriate location in the interrupt vector table. at this point, a jump instruction to the appropriate isr is required. in the event of a motor control peripheral interrupt, the opera- tion is slightly different. when a peripheral interrupt is de- tected, a bit is set in the irqflag register for pwmsync and pwmtrip or in the pioflag0, or pioflag1 or pioflag2 registers for a pio interrupt, and the irq2 line is pulled low until all pending interrupts are acknowledged. for any of the twenty six peripheral interrupts, the interrupt control- ler automatically jumps to location 0x0004 in the interrupt vector table. code loaded at location 0x0004 by the monitor on reset subsequently reads the irqflag register to determine if the source of the interrupt was a pwm trip, pwmsync or pios and vectors to the appropriate interrupt vector location. the code located at location 0x0004 by the monitor on reset is as follows: 0x0004: astat = dm(irqflag); dm(irqflag_save) = astat; if eq jump 0x002c if lt jump 0x000c; at this point, a jump instruction to the appropriate isr, at the interrupt vector location shown in table ix, is required. if more than one interrupt occurs simultaneously, the higher prior- ity interrupt service routine is executed. reading the irqflag register clears the pwmtrip and pwmsync bits and ac- knowledges the interrupt, thus allowing further interrupts when the isr exits. when the irqflag register is read, it is saved in a data memory variable so the user isr can check to see if there are simultaneous pwmsync and pwmtrip interrupts. a user s pio interrupt service routine must read the pioflag0, pioflag1 and pioflag2 registers to determine which pio port is the source of the interrupt. reading pioflag0, pioflag1 and pioflag2 registers clear all bits in the regis- ters and acknowledge the interrupt, thus allowing further inter- rupts when the isr exits. the configuration of all these registers is shown at the end of the data sheet. system controller the system controller block of the admc331 performs a num- ber of distinct functions: 1. manages the interface and data transfer between the dsp core and the motor control peripherals. 2. handles interrupts generated by the motor control periph- erals and generates a dsp core interrupt signal irq2 . 3. controls the adc multiplexer select lines. 4. enables pwmtrip and pwmsync interrupts. 5. controls the multiplexing of the sport1 pins to select either dr1a or dr1b data receive pins. it also allows configuration of sport1 as a uart interface.
admc331 C23C rev. b 6. controls the pwm single/double update mode. 7. controls the adc conversion time modes. 8. controls the auxpwm mode. 9. contains a status register (sysstat) that indicates the state of the pwmtrip , pwmpol and pwmsr pins, the watchdog timer and the pwm timer. 10. performs a reset of the motor control peripherals and con- trol registers following a hardware, software or watchdog initiated reset. dsp core sport1 dr1a dr1b tfs1 rfs1/ srom sclk1 modectrl (5 . . . 4) uarten dr1sel dt1 dr1 tfs1 rfs1 sclk1 fl1 admc331 dt1 figure 15. internal multiplexing of sport1 pins sport1 control the admc331 uses sport1 as the default serial port for boot loading and as the interface to the development environment. there are two data receive pins, dr1a and dr1b, on the admc331. this permits dr1a to be used as the data receive pin when interfacing to serial rom or e 2 prom for boot load- ing. alternatively, if connecting through another external device for either boot loading or interface to the development environ- ment, the dr1b pin can be used. both data receive pins are multiplexed internally into the single data receive input of sport1. two control bits in the modectrl register control the state of the sport1 pins by manipulating internal multi- plexers in the admc331. the configuration of sport1 is illustrated in figure 15. bit 4 of the modectrl register (dr1sel) selects between the two data receive pins. setting bit 4 of modectrl con- nects the dr1b pin to the internal data receive port dr1 of sport1. clearing bit 4 connects dr1a to dr1. setting bit 5 of the modectrl register (uarten) config- ures the serial port for uart mode. in this mode, the dr1 and rfs1 pins of the internal serial port are connected together. additionally, setting the uarten bit connects the fl1 flag of the dsp to the external rfs1/ srom pin. in this mode, this pin is intended to be used to reset the external serial rom device. the monitor code in rom automatically configures the sport1 pins during the boot sequence. initially, the dr1sel bit is cleared and the uarten bit is set so that the admc331 first attempts to perform a reset of the external memory device using the rfs1/ srom pin. this is accomplished by toggling the fl1 flag using the following code segment: sromreset: set fl1; toggle fl1; toggle fl1; rts; if successful, data will be clocked from the external device in a continuous stream. the start of the data stream is detected by the serial port on the rfs1 pin, which is connected internally to the dr1 pin in this mode. if the serial load is successful, code is downloaded and execution begins at the start of user program memory (address 0x0030). following a srom/e 2 prom boot load, sport1 could be configured for normal synchronous serial mode by setting the dr1sel pin to select the dr1b data receive pin and by clearing the uarten bit to return to sport mode. failing a srom/e 2 prom boot load, the admc331 monitor automatically sets the dr1sel bit to select the dr1b pin and remains in uarten mode. the monitor code then waits for a header byte that tells it with which of the other interfaces it is to communicate. obviously, if a debugger interface is required on sport1, it is not possible to use sport1 as a general purpose synchronous serial port. if such a serial port is required, it is recommended that sport0 be used. flag pins the admc331 provides flag pins. the alternate configuration of sport1 includes a flag in (fi) and flag out (fo) pin. this alternate configuration of sport1 is selected by bit 10 of the dsp system control register, syscntl at data memory address, 0x3fff. in the alternate configuration, the dr1 pin (either dr1a or dr1b depending on the state of the dr1sel bit) becomes the fi pin and the dt1 pin becomes the fo pin. additionally, rfs1 is configured as the irq0 interrupt input and tfs1 is configured as the irq1 interrupt. the serial port clock, sclk1, is still available in the alternate configuration. following boot loading from a serial memory device, it is pos- sible to reconfigure the sport1 to this alternate configuration. however, if a debugger interface is used, this configuration is not possible as the normal serial port pins are required for debugger communications. the admc331 also contains two software flags, fl1 and fl2. these flags may be controlled in software and perform specific functions on the admc331. the fl1 pin has already been described and is used to perform a reset of the external memory device via the rfs1/ srom pin. the fl2 flag is used specifi- cally to perform a full peripheral reset of the chip (including the watchdog timer). this is accomplished by toggling the fl2 flag in software using the following code segment: preset: set fl2: toggle fl2; toggle fl2; rts;
admc331 C24C rev. b table x. peripheral register map address offset (hex) (decimal) name bits used function 0x2000 0 adc1 [15 . . . 4] adc results for v1 0x2001 1 adc2 [15 . . . 4] adc results for v2 0x2002 2 adc3 [15 . . . 4] adc results for v3 0x2003 3 adcaux [15 . . . 4] adc results for vaux 0x2004 4 piodir0 [7 . . . 0] pio0 . . . 7 pins direction setting 0x2005 5 piodata0 [7 . . . 0] pio0 . . . 7 pins input/output data 0x2006 6 piointen0 [7 . . . 0] pio0 . . . 7 pins interrupt enable 0x2007 7 pioflag0 [7 . . . 0] pio0 . . . 7 pins interrupt status 0x2008 8 pwmtm [15 . . . 0] pwm period 0x2009 9 pwmdt [9 . . . 0] pwm deadtime 0x200a 10 pwmpd [9 . . . 0] pwm pulse deletion time 0x200b 11 pwmgate [9 . . . 0] pwm gate drive configuration 0x200c 12 pwmcha [15 . . . 0] pwm channel a pulsewidth 0x200d 13 pwmchb [15 . . . 0] pwm channel b pulsewidth 0x200e 14 pwmchc pwm channel c pulsewidth 0x200f 15 pwmseg [8 . . . 0] pwm segment select 0x2010 16 auxch0 [7 . . . 0] aux pwm output 0 0x2011 17 auxch1 [7 . . . 0] aux pwm output 1 0x2012 18 auxtm0 [7 . . . 0] auxiliary pwm frequency value 0x2013 19 auxtm1 [7 . . . 0] auxiliary pwm frequency value/offset 0x2014 20 reserved 0x2015 21 modectrl [8 . . . 0] system control register 0x2016 22 sysstat [4 . . . 0] system status 0x2017 23 irqflag [1 . . . 0] interrupt status 0x2018 24 wdtimer [15 . . . 0] watchdog timer 0x2019 . . . 3f 25 . . . 63 reserved 0x2040 . . . 43 64 . . . 67 reserved 0x2044 68 piodir1 [7 . . . 0] pio8 . . . 15 pins direction setting 0x2045 69 piodata1 [7 . . . 0] pio8 . . . 15 pins input/output data 0x2046 70 piointen1 [7 . . . 0] pio8 . . . 15 pins interrupt enable 0x2047 71 pioflag1 [7 . . . 0] pio8 . . . 15 pins interrupt status 0x2048 72 piodir2 [7 . . . 0] pio16 . . . 23 pins direction setting 0x2049 73 piodata2 [7 . . . 0] pio16 . . . 23 pins input/output data 0x204a 74 piointen2 [7 . . . 0] pio16 . . . 23 pins interrupt enable 0x204b 75 pioflag2 [7 . . . 0] pio16 . . . 23 pins interrupt status 0x204c ...4f 76...79 r eserved 0x2050 . . . 5f 80 . . . 95 reserved 0x2060 96 pwmsyncwt [7 . . . 0] pwmsync pulsewidth 0x2061 97 pwmswt [0] pwm s/w trip bit 0x2062 . . . ff 98 . . . 255 reserved
admc331 C25C rev. b table xi. dsp core registers address name bits function 0x3fff syscntl [15 . . . 0] system control register 0x3ffe memwait [15 . . . 0] memory wait state control register 0x3ffd tperiod [15 . . . 0] interval timer period register 0x3ffc tcount [15 . . . 0] interval timer count register 0x3ffb tscale [7 ...0] interval timer scale register 0x3ffa sport0_rx_words1 [15 . . . 0] sport0 multichannel word 1 receive 0x3ff9 sport0_rx_words0 [15 . . . 0] sport0 multichannel word 0 receive 0x3ff8 sport0_tx_words1 [15 . . . 0] sport0 multichannel word 1 transmit 0x3ff7 sport0_tx_words0 [15 . . . 0] sport0 multichannel word 0 transmit 0x3ff6 sport0_ctrl_reg [15 . . . 0] sport0 control register 0x3ff5 sport0_sclkdiv [15 . . . 0] sport0 clock divide register 0x3ff4 sport0_rfsdiv [15 . . . 0] sport0 receive frame sync divide 0x3ff3 sport0_autobuf_ctrl [15 . . . 0] sport0 autobuffer control register 0x3ff2 sport1_ctrl_reg [15 . . . 0] sport1 control register 0x3ff1 sport1_sclkdiv [15 . . . 0] sport1 clock divide register 0x3ff0 sport1_rfsdiv [15 . . . 0] sport1 receive frame sync divide 0x3fef sport1_autobuf_ctrl [15 . . . 0] sport1 autobuffer control register
admc331 C26C rev. b system controller registers the system controller includes three registers, modectrl, sysstat and irqflag registers. the format of these regis- ters is shown at the end of the data sheet. the modectrl register controls different multiplexing, pwm interrupt and operating modes: bit 0 and 1 control the multiplexing of the adc auxiliary channels. bit 2 enables/disables the pwmtrip interrupt: if the bit is set the interrupt is enabled. bit 3 enables/disables the pwmsync interrupt: if the bit is set the interrupt is enabled. bit 4 controls the multiplexing of the sport1 pins: if the bit is set dr1b is selected. bit 5 controls the configuration of sport1 as a uart inter- face: if the bit is set uart mode is enabled. bit 6 selected the pwm operating mode: single or double duty cycle update modes. if the bit is set double update mode is selected. bit 7 selects the adc counter frequency: if the bit is set full dsp clkout frequency is selected. bit 8 selects the auxiliary pwm operating mode: offset or independent modes: if the bit is set independent mode is selected. the sysstat register displays various status information: bit 0 indicates the status of the pwmtrip pin: if this bit is high, then pwmtrip pin is high and no pwmtrip is oc- curring, if this bit is low, then the pwm is currently shut down. bit 1 indicates the status of the watchdog flag register: this bit is set following a watchdog timeout. bit 2 indicates the status of the pwmpol pin: if this bit is set, the pwmpol pin is high and active high pwm outputs will be produced. bit 3 indicates the status of the pwm timer. bit 4 indicates the status of the pwmsr pin: if this bit is set to a logic one, the pwmsr pin is low and switched reluc- tance mode is enabled. the irqflag register indicates the occurrence of pwm interrupts: bit 0 indicates that a pwmtrip interrupt, either hardware of software, has occurred. bit 1 indicates that a pwmsync interrupt has occurred. register memory map the address, name, used bits and function of all motor control peripheral registers of the admc331 are tabulated in table x. in addition, the relevant dsp core registers are tabulated in table xi. full details of the dsp core registers can be obtained by referring to the adsp-2171 sections of the adsp-2100 family user s manual, third edition. development kit to facilitate device evaluation and programming, an evaluation kit (admc331-eval kit) is available from analog devices. the evaluation kit consists of an evaluation board and the motion control debugger software. the evaluation kit con- tains latest programming and device information. it is recom- mended that the evaluation kit be used for initial program development.
admc331 C27C rev. b 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 000 0 0000 00 00 00 00 t d = 2 pwmdt f clkout seconds pwmdt (r/w) dm (0x2009) pwmdt f pwm = pwmtm (r/w) dm (0x2008) pwmtm 2 pwmtm f clkout 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 0 0 0 0 0 0 0 0 0 0 = enable 1 = disable ch output disable cl output disable bh output disable bl output disable ah output disable al output disable 0 = no crossover 1 = crossover a channel crossover b channel crossover c channel crossover dm (0x200f) pwmseg (r/w) 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 00 00 00 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 010 0 0111 00 00 00 00 pwmsyncwt (r/w) dm (0x2060) pwmsyncwt t pwmsync,on = pwmsyncwt + 1 f clkout 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 000 0 0000 0000 0000 pwmswt (r/w) dm (0x2061) figure 16. configuration of admc331 registers default bit values are shown; if no value is shown, the bit field is undefined at reset. reserved bits are shown on a gray fiel d these bits should always be written as shown.
admc331 C28C rev. b 0 0 0 0 0 0 0 0 0 0 low side gate chopping 0 = disable 1 = enable high side gate chopping dm (0x200b) gatetm gate drive chopping frequency pwmgate (r/w) pwmpd (r/w) dm (0x200a) pwmpd pwmcha (r/w) pwm channel a duty cycle dm (0x200c) pwmchb (r/w) pwm channel b duty cycle dm (0x200d) pwmchc (r/w) dm (0x200e) pwm channel c duty cycle t min = pwmpd f clkout seconds f chop = 4 (gatetm + 1) 0 0 0 0 0 0 0 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 0 0 0 0 0 0 0 0 f clkout figure 17. configuration of admc331 registers
admc331 C29C rev. b dm (0x2004) 0 = input 1 = output piodir0 (r/w) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 dm (0x2044) 0 = input 1 = output piodir1 (r/w) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 dm (0x2005) 0 = low level 1 = high level piodata0 (r/w) 0 0 0 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 dm (0x2045) 0 = low level 1 = high level piodata1 (r/w) 0 0 0 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 0 0 0 0 dm (0x2049) 0 = low level 1 = high level piodata2 (r/w) 0 0 0 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 0 0 0 0 0 0 0 0 0 = input 1 = output piodir2 (r/w) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 dm (0x2048) figure 18. configuration of admc331 registers default bit values are shown; if no value is shown, the bit field is undefined at reset. reserved bits are shown on a gray fiel d these bits should always be written as shown.
admc331 C30C rev. b pioflag0 (r) dm (0x2007) 0 = no interrupt 1 = interrupt flagged 0 0 0 0 0 0 0 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 dm (0x2006) piointen0 (r/w) 0 = interrupt disable 1 = interrupt enable 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 dm (0x2046) piointen1 (r/w) 0 = interrupt disable 1 = interrupt enable 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 dm (0x204a) piointen2 (r/w) 0 = interrupt disable 1 = interrupt enable 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 pioflag1 (r) dm (0x2047) 0 = no interrupt 1 = interrupt flagged 0 0 0 0 0 0 0 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 pioflag2 (r) dm (0x204b) 0 = no interrupt 1 = interrupt flagged 0 0 0 0 0 0 0 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 0 0 0 00 0 0 0 0 0 0 00 0 0 0 0 0 0 00 0 0 0 figure 19. configuration of admc331 registers
admc331 C31C rev. b default bit values are shown; if no value is shown, the bit field is undefined at reset. reserved bits are shown on a gray fiel d these bits should always be written as shown. auxch1 (r/w) dm (0x2011) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 auxch0 (r/w) dm (0x2010) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 auxtm0 (r/w) dm (0x2012) 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 auxtm1 (r/w) dm (0x2013) aux1 period = 2 (1 + auxtm1) t ck offset = 2 (1 + auxtm1) t ck 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 t on, aux0 = 2 (auxch0) t ck t on, aux1 = 2 (auxch1) t ck aux0 period = 2 (auxtm0 + 1) t ck figure 20. configuration of admc331 registers
admc331 C32C rev. b 0 0 0 0 dm (0x2000) adc1 (r) 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 0 0 0 0 dm (0x2001) adc2 (r) 151413121110987654 3210 0 0 0 0 dm (0x2002) adc3 (r) 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 0 0 0 0 dm (0x2003) adcaux (r) 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 figure 21. configuration of admc331 registers
admc331 C33C rev. b 0 0 0 0 0 0 00 0 0 0 sysstat (r) 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 0 = low 1 = high dm (0x2016) 0 = normal 1 = watchdog reset occurred pwmtrip pin status 0 = low 1 = high watchdog status pwmpol pin status pwmsr pin status 1 = sr mode 0 = normal pwm timer status 0 = 1st half of pwm cycle 1 = 2nd half of pwm cycle 0 0 00 0 0 0 00 0 0 00 0 0 0 modectrl (r/w) dm (0x2015) sport1 data receive select 0 = dr1a 1 = dr1b 0 = sport 1 = uart sport1 mode select pwm update mode select 0 = single update mode 1 = double update mode 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 adc mux control 00 vaux0 01 vaux1 10 vaux2 11 vaux3 pwmtrip interrupt 0 = disable 1 = enable pwmsync interrupt 0 = disable 1 = enable auxiliary pwm select 0 = offset mode 1 = independent mode adc counter select 0 = 1/2 dsp clockout frequency 1 = dsp clockout frequency 0 0 00 0 0 0 00 0 0 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 0 0 00 irqflag (r) pwmtrip 1 = active pwmsync 1 = active dm (0x2017) 0 0 0 0 0 0 00 0 0 00 0 0 00 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 wdtimer (w) dm (0x2018) figure 22. configuration of admc331 registers default bit values are shown; if no value is shown, the bit field is undefined at reset. reserved bits are shown on a gray fiel d these bits should always be written as shown.
admc331 C34C rev. b 1 1 0 0 0 irq0 sensitivity 0 = level 1 = edge icntl irq1 sensitivity irq2 sensitivity interrupt nesting 0 = disable 1 = enable dsp register sport1 receive or irq0 ifc interrupt force interrupt clear 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 timer software 0 software 1 sport0 receive sport0 transmit irq2 sport1 receive or irq0 timer software 0 software 1 sport0 receive sport0 transmit sport1 transmit or irq1 irq2 dsp register 43210 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 sport1 transmit or irq1 imask (r/w) peripheral (or irq2 ) reserved (set to 0) sport0 transmit sport0 receive timer sport1 receive (or irq0 ) sport1 transmit (or irq1 ) software 0 software 1 0 0 0 0 0 0 0 00 0 0 00 1 1 0 dsp register 0 = disable (mask) 1 = enable 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 0 = disable (mask) 1 = enable figure 23. configuration of admc331 registers
admc331 C35C rev. b 0 0 0 0 0 0 0 10 0 0 00 0 0 0 dm (0x3ffe) memwait (r/w) 0 0 0 0 0 0 0 00 0 1 10 0 0 0 sport1 configure 0 = fi, fo, irq0 , irq1 , sclk 1 = serial port sport0 enable sport1 enable 0 = disabled 1 = enabled 0 = disabled 1 = enabled syscntl (r/w) dm (0x3fff) 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 figure 24. configuration of admc331 registers
admc331 C36C rev. b outline dimensions dimensions shown in inches and (mm). c3299bC5C6/00 (rev. b) 00107 printed in u.s.a. 80-lead plastic thin quad flatpack (tqfp) (st-80) seating plane 0.063 (1.60) max 0.030 (0.75) 0.020 (0.50) 0.004 (0.10) max 0.057 (1.45) 0.053 (1.35) 0.006 (0.15) 0.002 (0.05) 0.014 (0.35) 0.010 (0.25) 0.640 (16.25) 0.620 (15.75) 0.553 (14.05) 0.549 (13.95) 0.553 (14.05) 0.549 (13.95 0.640 (16.25) 0.620 (15.75) 1 20 21 41 40 60 61 80 0.486 (12.35) typ 0.486 (12.35) typ top view (pins down) 0.029 (0.73) 0.022 (0.57)

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