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Add PWM Backlight #575

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hubmartin wants to merge 3 commits into from
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Add PWM Backlight #575

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266178d
Add PWM Backlight
hubmartin Aug 12, 2021
adf4979
Set low/med levels to be exactly same like without PWM
hubmartin Aug 14, 2021
ca0298b
Merge branch 'develop' into pwm-backlight
hubmartin Sep 16, 2021
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Add PWM Backlight
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@hubmartin
hubmartin committed Aug 12, 2021
commit 266178d7ae1490060924410bf1d551919edd280c
51 changes: 39 additions & 12 deletions src/components/brightness/BrightnessController.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2,38 +2,65 @@
#include <hal/nrf_gpio.h>
#include "displayapp/screens/Symbols.h"

#include "nrf_pwm.h"

using namespace Pinetime::Controllers;

void BrightnessController::Init() {

// Use only LIGHT1 mosfet with 30R resistor for now
nrf_gpio_cfg_output(pinLcdBacklight1);
nrf_gpio_cfg_output(pinLcdBacklight2);
nrf_gpio_cfg_output(pinLcdBacklight3);

nrf_gpio_pin_clear(pinLcdBacklight1);
nrf_gpio_pin_clear(pinLcdBacklight2);
nrf_gpio_pin_clear(pinLcdBacklight3);

static nrf_pwm_sequence_t seq;

seq.values.p_common = pwmSequence;
seq.length = 1;
seq.repeats = 0;
seq.end_delay = 0;

uint32_t out_pins[] = {pinLcdBacklight3, pinLcdBacklight2, pinLcdBacklight1, NRF_PWM_PIN_NOT_CONNECTED};

nrf_pwm_pins_set(NRF_PWM0, out_pins);
nrf_pwm_enable(NRF_PWM0);
// With 8 MHz and 10000 reload timer PWM frequency is 712 Hz
nrf_pwm_configure(NRF_PWM0, NRF_PWM_CLK_8MHz, NRF_PWM_MODE_UP, 10000);
nrf_pwm_loop_set(NRF_PWM0, 0);
nrf_pwm_decoder_set(NRF_PWM0, NRF_PWM_LOAD_COMMON, NRF_PWM_STEP_AUTO);
nrf_pwm_sequence_set(NRF_PWM0, 0, &seq);
nrf_pwm_task_trigger(NRF_PWM0, NRF_PWM_TASK_SEQSTART0);

Set(level);
}


void BrightnessController::setPwm(uint16_t val)
{
pwmSequence[0] = val;
nrf_pwm_task_trigger(NRF_PWM0, NRF_PWM_TASK_SEQSTART0);
}

void BrightnessController::Set(BrightnessController::Levels level) {

this->level = level;
switch (level) {
default:
case Levels::High:
nrf_gpio_pin_clear(pinLcdBacklight1);
nrf_gpio_pin_clear(pinLcdBacklight2);
nrf_gpio_pin_clear(pinLcdBacklight3);
setPwm(10000);
break;
case Levels::Medium:
nrf_gpio_pin_clear(pinLcdBacklight1);
nrf_gpio_pin_clear(pinLcdBacklight2);
nrf_gpio_pin_set(pinLcdBacklight3);
setPwm(5000);
break;
case Levels::Low:
nrf_gpio_pin_clear(pinLcdBacklight1);
nrf_gpio_pin_set(pinLcdBacklight2);
nrf_gpio_pin_set(pinLcdBacklight3);
setPwm(500);
break;
case Levels::Off:
nrf_gpio_pin_set(pinLcdBacklight1);
nrf_gpio_pin_set(pinLcdBacklight2);
nrf_gpio_pin_set(pinLcdBacklight3);
setPwm(0);
break;
}
}
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4 changes: 4 additions & 0 deletions src/components/brightness/BrightnessController.h
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Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,10 @@ namespace Pinetime {
static constexpr uint8_t pinLcdBacklight3 = 23;
Levels level = Levels::High;
Levels backupLevel = Levels::High;
uint16_t pwmSequence[1] = {10000};

void setPwm(uint16_t val);

};
}
}