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Fix incorrect PWM bit depth on Esp32 with XTAL clock #4082

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merged 4 commits into from
Aug 4, 2024
Merged

Fix incorrect PWM bit depth on Esp32 with XTAL clock #4082

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5c247d2
first implementation
PaoloTK Aug 1, 2024
1123d85
removed float math and log(), added max bit width
PaoloTK Aug 3, 2024
779744b
typo in comment
PaoloTK Aug 3, 2024
5254854
Remove clock/max bit overrides
blazoncek Aug 4, 2024
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38 changes: 28 additions & 10 deletions wled00/bus_manager.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -378,30 +378,48 @@ void BusDigital::cleanup() {
}


#ifdef ESP8266
// 1 MHz clock
#define CLOCK_FREQUENCY 1000000UL
#else
// Use XTAL clock if possible to avoid timer frequency error when setting APB clock < 80 Mhz
// https://github.com/espressif/arduino-esp32/blob/2.0.2/cores/esp32/esp32-hal-ledc.c
#ifdef SOC_LEDC_SUPPORT_XTAL_CLOCK
#define CLOCK_FREQUENCY 40000000UL
#else
#define CLOCK_FREQUENCY 80000000UL
#endif
#endif

#ifdef ESP8266
#define MAX_BIT_WIDTH 10
#else
#ifdef SOC_LEDC_TIMER_BIT_WIDE_NUM
// C6/H2/P4: 20 bit, S2/S3/C2/C3: 14 bit
#define MAX_BIT_WIDTH SOC_LEDC_TIMER_BIT_WIDE_NUM
#else
// ESP32: 20 bit (but in reality we would never go beyond 16 bit as the frequency would be to low)
#define MAX_BIT_WIDTH 20
#endif
#endif

BusPwm::BusPwm(BusConfig &bc)
: Bus(bc.type, bc.start, bc.autoWhite, 1, bc.reversed)
{
if (!IS_PWM(bc.type)) return;
unsigned numPins = NUM_PWM_PINS(bc.type);
_frequency = bc.frequency ? bc.frequency : WLED_PWM_FREQ;
// duty cycle resolution (_depth) can be extracted from this formula: CLOCK_FREQUENCY > _frequency * 2^_depth
for (_depth = MAX_BIT_WIDTH; _depth > 8; _depth--) if (((CLOCK_FREQUENCY/_frequency) >> _depth) > 0) break;

#ifdef ESP8266
// duty cycle resolution (_depth) can be extracted from this formula: 1MHz > _frequency * 2^_depth
if (_frequency > 1760) _depth = 8;
else if (_frequency > 880) _depth = 9;
else _depth = 10; // WLED_PWM_FREQ <= 880Hz
analogWriteRange((1<<_depth)-1);
analogWriteFreq(_frequency);
#else
_ledcStart = pinManager.allocateLedc(numPins);
if (_ledcStart == 255) { //no more free LEDC channels
deallocatePins(); return;
}
// duty cycle resolution (_depth) can be extracted from this formula: 80MHz > _frequency * 2^_depth
if (_frequency > 78124) _depth = 9;
else if (_frequency > 39062) _depth = 10;
else if (_frequency > 19531) _depth = 11;
else _depth = 12; // WLED_PWM_FREQ <= 19531Hz
#endif

for (unsigned i = 0; i < numPins; i++) {
Expand All @@ -419,7 +437,7 @@ BusPwm::BusPwm(BusConfig &bc)
}
_data = _pwmdata; // avoid malloc() and use stack
_valid = true;
DEBUG_PRINTF_P(PSTR("%successfully inited PWM strip with type %u and pins %u,%u,%u,%u,%u\n"), _valid?"S":"Uns", bc.type, _pins[0], _pins[1], _pins[2], _pins[3], _pins[4]);
DEBUG_PRINTF_P(PSTR("%successfully inited PWM strip with type %u, frequency %u, bit depth %u and pins %u,%u,%u,%u,%u\n"), _valid?"S":"Uns", bc.type, _frequency, _depth, _pins[0], _pins[1], _pins[2], _pins[3], _pins[4]);
}

void BusPwm::setPixelColor(uint16_t pix, uint32_t c) {
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