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https://github.com/MarlinFirmware/Marlin.git
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🐛 Fix FastPWM calculations (#25343)
Co-authored-by: Scott Lahteine <thinkyhead@users.noreply.github.com>
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196f403dd6
commit
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3 changed files with 40 additions and 25 deletions
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@ -23,6 +23,10 @@
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#include "../../inc/MarlinConfig.h"
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//#define DEBUG_AVR_FAST_PWM
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#define DEBUG_OUT ENABLED(DEBUG_AVR_FAST_PWM)
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#include "../../core/debug_out.h"
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struct Timer {
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volatile uint8_t* TCCRnQ[3]; // max 3 TCCR registers per timer
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volatile uint16_t* OCRnQ[3]; // max 3 OCR registers per timer
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@ -108,12 +112,15 @@ const Timer get_pwm_timer(const pin_t pin) {
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}
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void MarlinHAL::set_pwm_frequency(const pin_t pin, const uint16_t f_desired) {
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DEBUG_ECHOLNPGM("set_pwm_frequency(pin=", pin, ", freq=", f_desired, ")");
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const Timer timer = get_pwm_timer(pin);
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if (timer.isProtected || !timer.isPWM) return; // Don't proceed if protected timer or not recognized
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const bool is_timer2 = timer.n == 2;
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const uint16_t maxtop = is_timer2 ? 0xFF : 0xFFFF;
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DEBUG_ECHOLNPGM("maxtop=", maxtop);
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uint16_t res = 0xFF; // resolution (TOP value)
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uint8_t j = CS_NONE; // prescaler index
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uint8_t wgm = WGM_PWM_PC_8; // waveform generation mode
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@ -121,23 +128,29 @@ void MarlinHAL::set_pwm_frequency(const pin_t pin, const uint16_t f_desired) {
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// Calculating the prescaler and resolution to use to achieve closest frequency
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if (f_desired != 0) {
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constexpr uint16_t prescaler[] = { 1, 8, (32), 64, (128), 256, 1024 }; // (*) are Timer 2 only
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uint16_t f = (F_CPU) / (2 * 1024 * maxtop) + 1; // Start with the lowest non-zero frequency achievable (1 or 31)
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uint16_t f = (F_CPU) / (uint32_t(maxtop) << 11) + 1; // Start with the lowest non-zero frequency achievable (for 16MHz, 1 or 31)
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DEBUG_ECHOLNPGM("f=", f);
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DEBUG_ECHOLNPGM("(prescaler loop)");
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LOOP_L_N(i, COUNT(prescaler)) { // Loop through all prescaler values
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const uint16_t p = prescaler[i];
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const uint32_t p = prescaler[i]; // Extend to 32 bits for calculations
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DEBUG_ECHOLNPGM("prescaler[", i, "]=", p);
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uint16_t res_fast_temp, res_pc_temp;
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if (is_timer2) {
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#if ENABLED(USE_OCR2A_AS_TOP) // No resolution calculation for TIMER2 unless enabled USE_OCR2A_AS_TOP
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const uint16_t rft = (F_CPU) / (p * f_desired);
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res_fast_temp = rft - 1;
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res_pc_temp = rft / 2;
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DEBUG_ECHOLNPGM("(Timer2) res_fast_temp=", res_fast_temp, " res_pc_temp=", res_pc_temp);
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#else
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res_fast_temp = res_pc_temp = maxtop;
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DEBUG_ECHOLNPGM("(Timer2) res_fast_temp=", maxtop, " res_pc_temp=", maxtop);
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#endif
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}
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else {
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if (p == 32 || p == 128) continue; // Skip TIMER2 specific prescalers when not TIMER2
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const uint16_t rft = (F_CPU) / (p * f_desired);
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DEBUG_ECHOLNPGM("(Not Timer 2) F_CPU=" STRINGIFY(F_CPU), " prescaler=", p, " f_desired=", f_desired);
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res_fast_temp = rft - 1;
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res_pc_temp = rft / 2;
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}
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@ -147,23 +160,27 @@ void MarlinHAL::set_pwm_frequency(const pin_t pin, const uint16_t f_desired) {
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// Calculate frequencies of test prescaler and resolution values
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const uint16_t f_fast_temp = (F_CPU) / (p * (1 + res_fast_temp)),
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f_pc_temp = (F_CPU) / (2 * p * res_pc_temp);
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const int f_diff = _MAX(f, f_desired) - _MIN(f, f_desired),
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f_pc_temp = (F_CPU) / ((p * res_pc_temp) << 1),
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f_diff = _MAX(f, f_desired) - _MIN(f, f_desired),
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f_fast_diff = _MAX(f_fast_temp, f_desired) - _MIN(f_fast_temp, f_desired),
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f_pc_diff = _MAX(f_pc_temp, f_desired) - _MIN(f_pc_temp, f_desired);
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DEBUG_ECHOLNPGM("f_fast_temp=", f_fast_temp, " f_pc_temp=", f_pc_temp, " f_diff=", f_diff, " f_fast_diff=", f_fast_diff, " f_pc_diff=", f_pc_diff);
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if (f_fast_diff < f_diff && f_fast_diff <= f_pc_diff) { // FAST values are closest to desired f
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// Set the Wave Generation Mode to FAST PWM
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wgm = is_timer2 ? uint8_t(TERN(USE_OCR2A_AS_TOP, WGM2_FAST_PWM_OCR2A, WGM2_FAST_PWM)) : uint8_t(WGM_FAST_PWM_ICRn);
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// Remember this combination
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f = f_fast_temp; res = res_fast_temp; j = i + 1;
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DEBUG_ECHOLNPGM("(FAST) updated f=", f);
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}
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else if (f_pc_diff < f_diff) { // PHASE CORRECT values are closes to desired f
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// Set the Wave Generation Mode to PWM PHASE CORRECT
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wgm = is_timer2 ? uint8_t(TERN(USE_OCR2A_AS_TOP, WGM2_PWM_PC_OCR2A, WGM2_PWM_PC)) : uint8_t(WGM_PWM_PC_ICRn);
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f = f_pc_temp; res = res_pc_temp; j = i + 1;
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DEBUG_ECHOLNPGM("(PHASE) updated f=", f);
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}
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}
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} // prescaler loop
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}
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_SET_WGMnQ(timer, wgm);
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@ -342,16 +342,16 @@ void MarlinHAL::set_pwm_duty(const pin_t pin, const uint16_t v, const uint16_t v
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}
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else
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pindata.pwm_duty_ticks = duty; // PWM duty count = # of 4µs ticks per full PWM cycle
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return;
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}
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else
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#endif
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{
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const int8_t cid = get_pwm_channel(pin, PWM_FREQUENCY, PWM_RESOLUTION);
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if (cid >= 0) {
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const uint32_t duty = map(invert ? v_size - v : v, 0, v_size, 0, _BV(PWM_RESOLUTION)-1);
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ledcWrite(cid, duty);
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}
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}
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const int8_t cid = get_pwm_channel(pin, PWM_FREQUENCY, PWM_RESOLUTION);
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if (cid >= 0) {
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const uint32_t duty = map(invert ? v_size - v : v, 0, v_size, 0, _BV(PWM_RESOLUTION)-1);
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ledcWrite(cid, duty);
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}
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}
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int8_t MarlinHAL::set_pwm_frequency(const pin_t pin, const uint32_t f_desired) {
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@ -360,17 +360,15 @@ int8_t MarlinHAL::set_pwm_frequency(const pin_t pin, const uint32_t f_desired) {
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pwm_pin_data[pin & 0x7F].pwm_cycle_ticks = 1000000UL / f_desired / 4; // # of 4µs ticks per full PWM cycle
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return 0;
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}
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else
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#endif
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{
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const int8_t cid = channel_for_pin(pin);
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if (cid >= 0) {
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if (f_desired == ledcReadFreq(cid)) return cid; // no freq change
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ledcDetachPin(chan_pin[cid]);
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chan_pin[cid] = 0; // remove old freq channel
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}
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return get_pwm_channel(pin, f_desired, PWM_RESOLUTION); // try for new one
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}
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const int8_t cid = channel_for_pin(pin);
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if (cid >= 0) {
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if (f_desired == ledcReadFreq(cid)) return cid; // no freq change
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ledcDetachPin(chan_pin[cid]);
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chan_pin[cid] = 0; // remove old freq channel
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}
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return get_pwm_channel(pin, f_desired, PWM_RESOLUTION); // try for new one
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}
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// use hardware PWM if avail, if not then ISR
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@ -39,7 +39,7 @@ inline uint8_t timer_and_index_for_pin(const pin_t pin, timer_dev **timer_ptr) {
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void MarlinHAL::set_pwm_duty(const pin_t pin, const uint16_t v, const uint16_t v_size/*=255*/, const bool invert/*=false*/) {
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const uint16_t duty = invert ? v_size - v : v;
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if (PWM_PIN(pin)) {
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timer_dev *timer; UNUSED(timer);
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timer_dev *timer;
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if (timer_freq[timer_and_index_for_pin(pin, &timer)] == 0)
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set_pwm_frequency(pin, PWM_FREQUENCY);
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const uint8_t channel = PIN_MAP[pin].timer_channel;
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@ -55,7 +55,7 @@ void MarlinHAL::set_pwm_duty(const pin_t pin, const uint16_t v, const uint16_t v
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void MarlinHAL::set_pwm_frequency(const pin_t pin, const uint16_t f_desired) {
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if (!PWM_PIN(pin)) return; // Don't proceed if no hardware timer
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timer_dev *timer; UNUSED(timer);
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timer_dev *timer;
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timer_freq[timer_and_index_for_pin(pin, &timer)] = f_desired;
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// Protect used timers
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