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⚗️ Use pwm_set_duty over analogWrite to set PWM (#23048)

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Co-authored-by: Scott Lahteine <thinkyhead@users.noreply.github.com>
This commit is contained in:
Andrei M
2021-11-02 01:47:16 -04:00
committed by Scott Lahteine
parent b033da1782
commit 0d91b07797
26 changed files with 159 additions and 126 deletions
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2
Marlin/src/HAL/AVR/HAL.h
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@ -221,7 +221,7 @@ void set_pwm_frequency(const pin_t pin, int f_desired);
/**
* set_pwm_duty
* Sets the PWM duty cycle of the provided pin to the provided value
* Set the PWM duty cycle of the provided pin to the provided value
* Optionally allows inverting the duty cycle [default = false]
* Optionally allows changing the maximum size of the provided value to enable finer PWM duty control [default = 255]
*/

64
Marlin/src/HAL/AVR/fast_pwm.cpp
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@ -22,11 +22,10 @@
#ifdef __AVR__
#include "../../inc/MarlinConfigPre.h"
#include "HAL.h"
#if NEEDS_HARDWARE_PWM // Specific meta-flag for features that mandate PWM
#include "HAL.h"
struct Timer {
volatile uint8_t* TCCRnQ[3]; // max 3 TCCR registers per timer
volatile uint16_t* OCRnQ[3]; // max 3 OCR registers per timer
@ -153,7 +152,7 @@ Timer get_pwm_timer(const pin_t pin) {
void set_pwm_frequency(const pin_t pin, int f_desired) {
Timer timer = get_pwm_timer(pin);
if (timer.n == 0) return; // Don't proceed if protected timer or not recognised
if (timer.n == 0) return; // Don't proceed if protected timer or not recognized
uint16_t size;
if (timer.n == 2) size = 255; else size = 65535;
@ -243,40 +242,39 @@ void set_pwm_frequency(const pin_t pin, int f_desired) {
_SET_ICRn(timer.ICRn, res); // Set ICRn value (TOP) = res
}
#endif // NEEDS_HARDWARE_PWM
void set_pwm_duty(const pin_t pin, const uint16_t v, const uint16_t v_size/*=255*/, const bool invert/*=false*/) {
// If v is 0 or v_size (max), digitalWrite to LOW or HIGH.
// Note that digitalWrite also disables pwm output for us (sets COM bit to 0)
if (v == 0)
digitalWrite(pin, invert);
else if (v == v_size)
digitalWrite(pin, !invert);
else {
Timer timer = get_pwm_timer(pin);
if (timer.n == 0) return; // Don't proceed if protected timer or not recognised
// Set compare output mode to CLEAR -> SET or SET -> CLEAR (if inverted)
_SET_COMnQ(timer.TCCRnQ, (timer.q
#ifdef TCCR2
+ (timer.q == 2) // COM20 is on bit 4 of TCCR2, thus requires q + 1 in the macro
#endif
), COM_CLEAR_SET + invert
);
#if NEEDS_HARDWARE_PWM
uint16_t top;
if (timer.n == 2) { // if TIMER2
top = (
#if ENABLED(USE_OCR2A_AS_TOP)
*timer.OCRnQ[0] // top = OCR2A
#else
255 // top = 0xFF (max)
#endif
// If v is 0 or v_size (max), digitalWrite to LOW or HIGH.
// Note that digitalWrite also disables pwm output for us (sets COM bit to 0)
if (v == 0)
digitalWrite(pin, invert);
else if (v == v_size)
digitalWrite(pin, !invert);
else {
Timer timer = get_pwm_timer(pin);
if (timer.n == 0) return; // Don't proceed if protected timer or not recognized
// Set compare output mode to CLEAR -> SET or SET -> CLEAR (if inverted)
_SET_COMnQ(timer.TCCRnQ, (timer.q
#ifdef TCCR2
+ (timer.q == 2) // COM20 is on bit 4 of TCCR2, thus requires q + 1 in the macro
#endif
), COM_CLEAR_SET + invert
);
}
else
top = *timer.ICRn; // top = ICRn
_SET_OCRnQ(timer.OCRnQ, timer.q, v * float(top) / float(v_size)); // Scale 8/16-bit v to top value
}
uint16_t top = (timer.n == 2) ? TERN(USE_OCR2A_AS_TOP, *timer.OCRnQ[0], 255) : *timer.ICRn;
_SET_OCRnQ(timer.OCRnQ, timer.q, (v * top + v_size / 2) / v_size); // Scale 8/16-bit v to top value
}
#else
analogWrite(pin, v);
UNUSED(v_size);
UNUSED(invert);
#endif
}
#endif // NEEDS_HARDWARE_PWM
#endif // __AVR__