123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152 |
- /*
- * david austin
- * http://www.embedded.com/design/mcus-processors-and-socs/4006438/Generate-stepper-motor-speed-profiles-in-real-time
- * DECEMBER 30, 2004
- *
- * Demo program for stepper motor control with linear ramps
- * Hardware: PIC18F252, L6219
- *
- * Copyright (c) 2015 Robert Ramey
- *
- * Distributed under the Boost Software License, Version 1.0. (See
- * accompanying file LICENSE_1_0.txt or copy at
- * http://www.boost.org/LICENSE_1_0.txt)
- */
- // ramp state-machine states
- enum ramp_state {
- ramp_idle = 0,
- ramp_up = 1,
- ramp_max = 2,
- ramp_down = 3,
- ramp_last = 4,
- };
- enum ramp_state ramp_sts=ramp_idle;
- int16 motor_pos = 0; // absolute step number
- int16 pos_inc=0; // motor_pos increment
- uint16 phase=0; // ccpPhase[phase_ix]
- uint8 phase_ix=0; // index to ccpPhase[]
- uint8 phase_inc; // phase_ix increment
- uint8 run_flg; // true while motor is running
- uint16 ccpr; // copy of CCPR1&2
- uint16 c; // integer delay count
- uint16 step_no; // progress of move
- uint16 step_down; // start of down-ramp
- uint16 move; // total steps to move
- uint16 midpt; // midpoint of move
- uint32 c32; // 24.8 fixed point delay count
- int16 denom; // 4.n+1 in ramp algo
- // Config data to make CCP1&2 generate quadrature sequence on PHASE pins
- // Action on CCP match: 8=set+irq; 9=clear+irq
- uint16 const ccpPhase[] = {0x909, 0x908, 0x808, 0x809}; // 00,01,11,10
- void current_on(){/* code as needed */} // motor drive current
- void current_off(){/* code as needed */} // reduce to holding value
- uint16 make16(uint8 l, uint8 r) {
- return (uint16) l << 8 + r;
- }
- // compiler-specific ISR declaration
- void __interrupt isr_motor_step(void) { // CCP1 match -> step pulse + IRQ
- ccpr += c; // next comparator value
- switch (ramp_sts) {
- case ramp_up: // accel
- if (step_no == midpt) { // midpoint: decel
- ramp_sts = ramp_down;
- denom = ((step_no - move) << 2) + 1;
- if (!(move & 1)) { // even move: repeat last delay before decel
- denom += 4;
- break;
- }
- }
- // no break: share code for ramp algo
- case ramp_down: // decel
- if (step_no == move - 1) { // next irq is cleanup (no step)
- ramp_sts = ramp_last;
- break;
- }
- denom += 4;
- c32 -= (c32 << 1) / denom; // ramp algorithm
- // beware confict with foreground code if long div not reentrant
- c = (c32 + 128) >> 8; // round 24.8format->int16
- if (c <= C_MIN) { // go to constant speed
- ramp_sts = ramp_max;
- step_down = move - step_no;
- c = C_MIN;
- break;
- }
- break;
- case ramp_max: // constant speed
- if (step_no == step_down) { // start decel
- ramp_sts = ramp_down;
- denom = ((step_no - move) << 2) + 5;
- }
- break;
- default: // last step: cleanup
- ramp_sts = ramp_idle;
- current_off(); // reduce motor current to holding value
- CCP1IE = 0; // disable_interrupts(INT_CCP1);
- run_flg = false; // move complete
- break;
- } // switch (ramp_sts)
- if (ramp_sts != ramp_idle) {
- motor_pos += pos_inc;
- ++step_no;
- CCPR2H = CCPR1H = (ccpr >> 8); // timer value at next CCP match
- CCPR2L = CCPR1L = (ccpr & 0xff);
- if (ramp_sts != ramp_last) // else repeat last action: no step
- phase_ix = (phase_ix + phase_inc) & 3;
- phase = ccpPhase[phase_ix];
- CCP1CON = phase & 0xff; // set CCP action on next match
- CCP2CON = phase >> 8;
- } // if (ramp_sts != ramp_idle)
- } // isr_motor_step()
- void motor_run(int16 pos_new) { // set up to drive motor to pos_new (absolute step#)
- if (pos_new < motor_pos) { // get direction & #steps
- move = motor_pos - pos_new;
- pos_inc = -1;
- phase_inc = 0xff;
- }
- else if (pos_new != motor_pos) {
- move = pos_new - motor_pos;
- pos_inc = 1;
- phase_inc = 1;
- } else return; // already there
- midpt = (move - 1) >> 1;
- c = C0;
- c32 = c << 8; // keep c in 24.8 fixed-point format for ramp calcs
- step_no = 0; // step counter
- denom = 1; // 4.n+1, n=0
- ramp_sts = ramp_up; // start ramp state-machine
- run_flg = true;
- T1CONbits.TMR1ON = 0; // stop timer1;
- ccpr = make16(TMR1H, TMR1L); // 16bit value of Timer1
- ccpr += 1000; // 1st step + irq 1ms after timer1 restart
- CCPR2H = CCPR1H = (ccpr >> 8);
- CCPR2L = CCPR1L = (ccpr & 0xff);
- phase_ix = (phase_ix + phase_inc) & 3;
- phase = ccpPhase[phase_ix];
- CCP1CON = phase & 0xff; // sets action on match
- CCP2CON = phase >> 8;
- current_on(); // current in motor windings
- CCP1IE = 1; // enable_interrupts(INT_CCP1);
- T1CONbits.TMR1ON = 1; // restart timer1;
- } // motor_run()
- void initialize() {
- di(); // disable_interrupts(GLOBAL);
- CCP1IE = 0; // disable_interrupts(INT_CCP1);
- CCP2IE = 0; // disable_interrupts(INT_CCP2);
- PORTC = 0; // output_c(0);
- TRISC = 0; // set_tris_c(0);
- T3CON = 0;
- T1CON = 0x35;
- INTCONbits.PEIE = 1;
- INTCONbits.RBIF = 0;
- ei(); // enable_interrupts(GLOBAL);
- } // initialize()
|