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Dithering support & bugfix in UI

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Thanks to @dedehai & @zalatnaicsongor
This commit is contained in:
Blaz Kristan
2024-08-30 15:21:16 +02:00
parent c51ce2eec7
commit 0d035a08d6
3 changed files with 63 additions and 39 deletions
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69
wled00/bus_manager.cpp
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@@ -6,6 +6,7 @@
#include <IPAddress.h>
#ifdef ARDUINO_ARCH_ESP32
#include "driver/ledc.h"
#include "soc/ledc_struct.h"
#endif
#include "const.h"
#include "pin_manager.h"
@@ -392,7 +393,7 @@ void BusDigital::cleanup(void) {
#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
#define MAX_BIT_WIDTH 14
#endif
#endif
@@ -413,11 +414,13 @@ BusPwm::BusPwm(BusConfig &bc)
analogWriteRange((1<<_depth)-1);
analogWriteFreq(_frequency);
#else
// for 2 pin PWM CCT strip pinManager will make sure both LEDC channels are in the same speed group and sharing the same timer
_ledcStart = pinManager.allocateLedc(numPins);
if (_ledcStart == 255) { //no more free LEDC channels
pinManager.deallocateMultiplePins(pins, numPins, PinOwner::BusPwm);
return;
}
if (_needsRefresh) _depth = 8; // fixed 8 bit depth with 4 bit dithering (ESP8266 has no hardware to support dithering)
#endif
for (unsigned i = 0; i < numPins; i++) {
@@ -501,38 +504,62 @@ uint32_t BusPwm::getPixelColor(uint16_t pix) const {
void BusPwm::show() {
if (!_valid) return;
const unsigned numPins = getPins();
const unsigned maxBri = (1<<_depth);
const unsigned maxBri = (1<<_depth); // possible values: 16384 (14), 8192 (13), 4096 (12), 2048 (11), 1024 (10), 512 (9) and 256 (8)
// use CIE brightness formula
unsigned pwmBri = (unsigned)_bri * 100;
if (pwmBri < 2040)
pwmBri = ((pwmBri << _depth) + 115043) / 230087; //adding '0.5' before division for correct rounding
else {
// use CIE brightness formula to fit (or approximate linearity of) human eye perceived brightness
// the formula is based on 12 bit resolution as there is no need for greater precision
unsigned pwmBri = (unsigned)_bri * 100; // enlarge to use integer math for linear response
if (pwmBri < 2040) {
// linear response for values [0-20]
pwmBri = ((pwmBri << 12) + 115043) / 230087; //adding '0.5' before division for correct rounding
} else {
// cubic response for values [21-255]
pwmBri += 4080;
float temp = (float)pwmBri / 29580.0f;
temp = temp * temp * temp * maxBri;
temp = temp * temp * temp * 4095.0f;
pwmBri = (unsigned)temp;
}
// pwmBri is in range [0-4095]
// determine phase shift
[[maybe_unused]] unsigned phaseOffset = maxBri / numPins; // (maxBri is at _depth resolution)
// we will be phase shifting every channel by fixed amount (i times /2 or /3 or /4 or /5)
// phase shifting is only mandatory when using H-bridge to drive reverse-polarity PWM CCT (2 wire) LED type (with 180° phase)
// CCT additive blending must be 0 (WW & CW must not overlap) in such case
// for all other cases it will just try to "spread" the load on PSU
for (unsigned i = 0; i < numPins; i++) {
unsigned scaled = (_data[i] * pwmBri) / 255;
if (_reversed) scaled = maxBri - scaled;
// adjust "scaled" value (to fit resolution bounds)
if (_depth < 12 && !_needsRefresh) scaled >>= 12 - _depth; // normalize scaled value (if not using dithering)
else if (_depth > 12) scaled <<= _depth - 12; // scale to _depth if using >12 bit
if (_reversed) scaled = maxBri - scaled;
#ifdef ESP8266
analogWrite(_pins[i], scaled);
#else
unsigned channel = _ledcStart + i;
// determine phase shift POC for PWM CCT (credit @dedehai)
// phase shifting (180°) is only available for PWM CCT LED type if _needsRefresh is true (UI hack)
// and CCT blending is 0 (WW & CW must not overlap)
// this will allow using H-bridge to drive reverse-polarity CCT LED strip (2 wires)
// NOTE/TODO: if this has no side effects we may forego UI hack and the need for _needsRefresh
// we may even use phase shift to evenly distribute power across different pins
if (_type == TYPE_ANALOG_2CH && _needsRefresh && Bus::getCCTBlend() == 0) { // hacked to determine if phase shifted PWM is requested
unsigned maxDuty = (maxBri / numPins); // numPins is 2
if (scaled >= maxDuty) scaled = maxDuty - 1; // safety check & add dead time of 1 pulse when brightness is at 50%
ledc_set_duty_and_update((ledc_mode_t)(channel / 8), (ledc_channel_t)(channel % 8), scaled, maxDuty*i);
} else
ledcWrite(channel, scaled);
if (_type == TYPE_ANALOG_2CH && Bus::getCCTBlend() == 0) {
// pinManager will make sure both LEDC channels are in the same speed group and sharing the same timer
unsigned briLimit = phaseOffset << (_needsRefresh*4); // expand limit if using dithering (_depth==8, scaled is at 12 bit)
if (scaled >= briLimit) scaled = briLimit - 1; // safety check & 1 pulse dead time when brightness is at 50%
}
unsigned gr = channel/8; // high/low speed group
unsigned ch = channel%8; // group channel
if (_needsRefresh) {
// if _needsRefresh is true (UI hack) we are using dithering (credit @dedehai & @zalatnaicsongor)
// https://github.com/Aircoookie/WLED/pull/4115 and https://github.com/zalatnaicsongor/WLED/pull/1)
// directly write to LEDC struct as there is no HAL exposed function for dithering
// duty has 20 bit resolution with 4 fractional bits (24 bits in total)
// _depth is 8 bit in this case (and maxBri==256), scaled is still at 12 bit
LEDC.channel_group[gr].channel[ch].duty.duty = scaled; // write full 12 bit value (4 dithering bits)
LEDC.channel_group[gr].channel[ch].hpoint.hpoint = phaseOffset*i; // phaseOffset is at _depth resolution (8 bit)
ledc_update_duty((ledc_mode_t)gr, (ledc_channel_t)ch);
} else {
// scaled will be [0-((1<<_depth)-1)] and hpoint evenly distributed
ledc_set_duty_and_update((ledc_mode_t)gr, (ledc_channel_t)ch, scaled, phaseOffset*i);
//ledcWrite(channel, scaled);
}
#endif
}
}