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#include "BatteryController.h"
#include <hal/nrf_gpio.h>
#include <nrfx_saadc.h>
#include <libraries/log/nrf_log.h>
#include <algorithm>
#include <math.h>
using namespace Pinetime::Controllers;
Battery* Battery::instance = nullptr;
Battery::Battery() {
instance = this;
}
void Battery::Init() {
nrf_gpio_cfg_input(chargingPin, static_cast<nrf_gpio_pin_pull_t> GPIO_PIN_CNF_PULL_Pullup);
}
void Battery::Update() {
isCharging = !nrf_gpio_pin_read(chargingPin);
isPowerPresent = !nrf_gpio_pin_read(powerPresentPin);
if (isReading) {
return;
}
// Non blocking read
isReading = true;
SaadcInit();
nrfx_saadc_sample();
}
void Battery::adcCallbackStatic(nrfx_saadc_evt_t const* event) {
instance->SaadcEventHandler(event);
}
void Battery::SaadcInit() {
nrfx_saadc_config_t adcConfig = NRFX_SAADC_DEFAULT_CONFIG;
APP_ERROR_CHECK(nrfx_saadc_init(&adcConfig, adcCallbackStatic));
nrf_saadc_channel_config_t adcChannelConfig = {.resistor_p = NRF_SAADC_RESISTOR_DISABLED,
.resistor_n = NRF_SAADC_RESISTOR_DISABLED,
.gain = NRF_SAADC_GAIN1_5,
.reference = NRF_SAADC_REFERENCE_INTERNAL,
.acq_time = NRF_SAADC_ACQTIME_40US,
.mode = NRF_SAADC_MODE_SINGLE_ENDED,
.burst = NRF_SAADC_BURST_ENABLED,
.pin_p = batteryVoltageAdcInput,
.pin_n = NRF_SAADC_INPUT_DISABLED};
APP_ERROR_CHECK(nrfx_saadc_channel_init(0, &adcChannelConfig));
APP_ERROR_CHECK(nrfx_saadc_buffer_convert(&saadc_value, 1));
}
void Battery::SaadcEventHandler(nrfx_saadc_evt_t const* p_event) {
const uint16_t battery_max = 4180; // maximum voltage of battery ( max charging voltage is 4.21 )
const uint16_t battery_min = 3200; // minimum voltage of battery before shutdown ( depends on the battery )
if (p_event->type == NRFX_SAADC_EVT_DONE) {
APP_ERROR_CHECK(nrfx_saadc_buffer_convert(&saadc_value, 1));
// A hardware voltage divider divides the battery voltage by 2
// ADC gain is 1/5
// thus adc_voltage = battery_voltage / 2 * gain = battery_voltage / 10
// reference_voltage is 0.6V
// p_event->data.done.p_buffer[0] = (adc_voltage / reference_voltage) * 1024
voltage = p_event->data.done.p_buffer[0] * 6000 / 1024;
percentRemaining = (voltage - battery_min) * 100 / (battery_max - battery_min);
percentRemaining = std::max(percentRemaining, 0);
percentRemaining = std::min(percentRemaining, 100);
nrfx_saadc_uninit();
isReading = false;
}
}
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