diff --git a/Marlin/Configuration.h b/Marlin/Configuration.h index b582143859..3facece4b7 100644 --- a/Marlin/Configuration.h +++ b/Marlin/Configuration.h @@ -1425,6 +1425,12 @@ // at zero value, there are 128 effective control positions. #define SOFT_PWM_SCALE 0 +// If SOFT_PWM_SCALE is set to a value higher than 0, dithering can +// be used to mitigate the associated resolution loss. If enabled, +// some of the PWM cycles are stretched so on average the wanted +// duty cycle is attained. +//#define SOFT_PWM_DITHER + // Temperature status LEDs that display the hotend and bed temperature. // If all hotends and bed temperature and temperature setpoint are < 54C then the BLUE led is on. // Otherwise the RED led is on. There is 1C hysteresis. diff --git a/Marlin/temperature.cpp b/Marlin/temperature.cpp index 883133806e..50a8f7b1d2 100644 --- a/Marlin/temperature.cpp +++ b/Marlin/temperature.cpp @@ -1512,6 +1512,8 @@ void Temperature::isr() { static uint8_t temp_count = 0; static TempState temp_state = StartupDelay; static uint8_t pwm_count = _BV(SOFT_PWM_SCALE); + // avoid multiple loads of pwm_count + uint8_t pwm_count_tmp = pwm_count; // Static members for each heater #if ENABLED(SLOW_PWM_HEATERS) @@ -1521,7 +1523,7 @@ void Temperature::isr() { static uint8_t state_heater_ ## n = 0; \ static uint8_t state_timer_heater_ ## n = 0 #else - #define ISR_STATICS(n) static uint8_t soft_pwm_ ## n + #define ISR_STATICS(n) static uint8_t soft_pwm_ ## n = 0 #endif // Statics per heater @@ -1544,72 +1546,82 @@ void Temperature::isr() { #endif #if DISABLED(SLOW_PWM_HEATERS) + constexpr uint8_t pwm_mask = + #if ENABLED(SOFT_PWM_DITHER) + _BV(SOFT_PWM_SCALE) - 1 + #else + 0 + #endif + ; + /** * Standard PWM modulation */ - if (pwm_count == 0) { - soft_pwm_0 = soft_pwm[0]; - WRITE_HEATER_0(soft_pwm_0 > 0 ? HIGH : LOW); + if (pwm_count_tmp >= 127) { + pwm_count_tmp -= 127; + soft_pwm_0 = (soft_pwm_0 & pwm_mask) + soft_pwm[0]; + WRITE_HEATER_0(soft_pwm_0 > pwm_mask ? HIGH : LOW); #if HOTENDS > 1 - soft_pwm_1 = soft_pwm[1]; - WRITE_HEATER_1(soft_pwm_1 > 0 ? HIGH : LOW); + soft_pwm_1 = (soft_pwm_1 & pwm_mask) + soft_pwm[1]; + WRITE_HEATER_1(soft_pwm_1 > pwm_mask ? HIGH : LOW); #if HOTENDS > 2 - soft_pwm_2 = soft_pwm[2]; - WRITE_HEATER_2(soft_pwm_2 > 0 ? HIGH : LOW); + soft_pwm_2 = (soft_pwm_2 & pwm_mask) + soft_pwm[2]; + WRITE_HEATER_2(soft_pwm_2 > pwm_mask ? HIGH : LOW); #if HOTENDS > 3 - soft_pwm_3 = soft_pwm[3]; - WRITE_HEATER_3(soft_pwm_3 > 0 ? HIGH : LOW); + soft_pwm_3 = (soft_pwm_3 & pwm_mask) + soft_pwm[3]; + WRITE_HEATER_3(soft_pwm_3 > pwm_mask ? HIGH : LOW); #endif #endif #endif #if HAS_HEATER_BED - soft_pwm_BED = soft_pwm_bed; - WRITE_HEATER_BED(soft_pwm_BED > 0 ? HIGH : LOW); + soft_pwm_BED = (soft_pwm_BED & pwm_mask) + soft_pwm_bed; + WRITE_HEATER_BED(soft_pwm_BED > pwm_mask ? HIGH : LOW); #endif #if ENABLED(FAN_SOFT_PWM) #if HAS_FAN0 - soft_pwm_fan[0] = fanSpeedSoftPwm[0] >> 1; - WRITE_FAN(soft_pwm_fan[0] > 0 ? HIGH : LOW); + soft_pwm_fan[0] = (soft_pwm_fan[0] & pwm_mask) + fanSpeedSoftPwm[0] >> 1; + WRITE_FAN(soft_pwm_fan[0] > pwm_mask ? HIGH : LOW); #endif #if HAS_FAN1 - soft_pwm_fan[1] = fanSpeedSoftPwm[1] >> 1; - WRITE_FAN1(soft_pwm_fan[1] > 0 ? HIGH : LOW); + soft_pwm_fan[1] = (soft_pwm_fan[1] & pwm_mask) + fanSpeedSoftPwm[1] >> 1; + WRITE_FAN1(soft_pwm_fan[1] > pwm_mask ? HIGH : LOW); #endif #if HAS_FAN2 - soft_pwm_fan[2] = fanSpeedSoftPwm[2] >> 1; - WRITE_FAN2(soft_pwm_fan[2] > 0 ? HIGH : LOW); + soft_pwm_fan[2] = (soft_pwm_fan[2] & pwm_mask) + fanSpeedSoftPwm[2] >> 1; + WRITE_FAN2(soft_pwm_fan[2] > pwm_mask ? HIGH : LOW); #endif #endif } - - if (soft_pwm_0 < pwm_count) WRITE_HEATER_0(0); - #if HOTENDS > 1 - if (soft_pwm_1 < pwm_count) WRITE_HEATER_1(0); + else { + if (soft_pwm_0 <= pwm_count_tmp) WRITE_HEATER_0(0); + #if HOTENDS > 1 + if (soft_pwm_1 <= pwm_count_tmp) WRITE_HEATER_1(0); + #endif #if HOTENDS > 2 - if (soft_pwm_2 < pwm_count) WRITE_HEATER_2(0); - #if HOTENDS > 3 - if (soft_pwm_3 < pwm_count) WRITE_HEATER_3(0); - #endif + if (soft_pwm_2 <= pwm_count_tmp) WRITE_HEATER_2(0); #endif - #endif - - #if HAS_HEATER_BED - if (soft_pwm_BED < pwm_count) WRITE_HEATER_BED(0); - #endif - - #if ENABLED(FAN_SOFT_PWM) - #if HAS_FAN0 - if (soft_pwm_fan[0] < pwm_count) WRITE_FAN(0); + #if HOTENDS > 3 + if (soft_pwm_3 <= pwm_count_tmp) WRITE_HEATER_3(0); #endif - #if HAS_FAN1 - if (soft_pwm_fan[1] < pwm_count) WRITE_FAN1(0); + + #if HAS_HEATER_BED + if (soft_pwm_BED <= pwm_count_tmp) WRITE_HEATER_BED(0); #endif - #if HAS_FAN2 - if (soft_pwm_fan[2] < pwm_count) WRITE_FAN2(0); + + #if ENABLED(FAN_SOFT_PWM) + #if HAS_FAN0 + if (soft_pwm_fan[0] <= pwm_count_tmp) WRITE_FAN(0); + #endif + #if HAS_FAN1 + if (soft_pwm_fan[1] <= pwm_count_tmp) WRITE_FAN1(0); + #endif + #if HAS_FAN2 + if (soft_pwm_fan[2] <= pwm_count_tmp) WRITE_FAN2(0); + #endif #endif - #endif + } // SOFT_PWM_SCALE to frequency: // @@ -1619,8 +1631,7 @@ void Temperature::isr() { // 3: / 16 = 61.0352 Hz // 4: / 8 = 122.0703 Hz // 5: / 4 = 244.1406 Hz - pwm_count += _BV(SOFT_PWM_SCALE); - pwm_count &= 0x7F; + pwm_count = pwm_count_tmp + _BV(SOFT_PWM_SCALE); #else // SLOW_PWM_HEATERS @@ -1694,7 +1705,8 @@ void Temperature::isr() { #endif #if ENABLED(FAN_SOFT_PWM) - if (pwm_count == 0) { + if (pwm_count_tmp >= 127) { + pwm_count_tmp = 0; #if HAS_FAN0 soft_pwm_fan[0] = fanSpeedSoftPwm[0] >> 1; WRITE_FAN(soft_pwm_fan[0] > 0 ? HIGH : LOW); @@ -1709,15 +1721,15 @@ void Temperature::isr() { #endif } #if HAS_FAN0 - if (soft_pwm_fan[0] < pwm_count) WRITE_FAN(0); + if (soft_pwm_fan[0] <= pwm_count_tmp) WRITE_FAN(0); #endif #if HAS_FAN1 - if (soft_pwm_fan[1] < pwm_count) WRITE_FAN1(0); + if (soft_pwm_fan[1] <= pwm_count_tmp) WRITE_FAN1(0); #endif #if HAS_FAN2 - if (soft_pwm_fan[2] < pwm_count) WRITE_FAN2(0); + if (soft_pwm_fan[2] <= pwm_count_tmp) WRITE_FAN2(0); #endif - #endif //FAN_SOFT_PWM + #endif // FAN_SOFT_PWM // SOFT_PWM_SCALE to frequency: // @@ -1727,13 +1739,13 @@ void Temperature::isr() { // 3: / 16 = 61.0352 Hz // 4: / 8 = 122.0703 Hz // 5: / 4 = 244.1406 Hz - pwm_count += _BV(SOFT_PWM_SCALE); - pwm_count &= 0x7F; + pwm_count = pwm_count_tmp + _BV(SOFT_PWM_SCALE); - // increment slow_pwm_count only every 64 pwm_count (e.g., every 8s) - if ((pwm_count % 64) == 0) { + // increment slow_pwm_count only every 64th pwm_count, + // i.e. yielding a PWM frequency of 16/128 Hz (8s). + if (((pwm_count >> SOFT_PWM_SCALE) & 0x3F) == 0) { slow_pwm_count++; - slow_pwm_count &= 0x7f; + slow_pwm_count &= 0x7F; // EXTRUDER 0 if (state_timer_heater_0 > 0) state_timer_heater_0--; @@ -1749,7 +1761,7 @@ void Temperature::isr() { #if HAS_HEATER_BED if (state_timer_heater_BED > 0) state_timer_heater_BED--; #endif - } // (pwm_count % 64) == 0 + } // ((pwm_count >> SOFT_PWM_SCALE) & 0x3F) == 0 #endif // SLOW_PWM_HEATERS