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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;
#define SAMPLES_IN_BUFFER 1
static nrf_saadc_value_t m_buffer_pool[2][SAMPLES_IN_BUFFER];
static float voltage = 0.0f;
static int percentRemaining = -1;
void Battery::Init() {
nrf_gpio_cfg_input(chargingPin, (nrf_gpio_pin_pull_t)GPIO_PIN_CNF_PULL_Pullup);
nrf_gpio_cfg_input(powerPresentPin, (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);
// Non blocking read
SaadcInit();
nrfx_saadc_sample();
}
void Battery::SaadcInit() {
nrfx_saadc_config_t adcConfig = NRFX_SAADC_DEFAULT_CONFIG;
APP_ERROR_CHECK(nrfx_saadc_init(&adcConfig, SaadcEventHandler));
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_3US,
.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(m_buffer_pool[0],SAMPLES_IN_BUFFER));
APP_ERROR_CHECK(nrfx_saadc_buffer_convert(m_buffer_pool[1],SAMPLES_IN_BUFFER));
}
void Battery::SaadcEventHandler(nrfx_saadc_evt_t const * p_event) {
int avg_sample = 0;
int i = 0;
const float battery_max = 4.18; //maximum voltage of battery ( max charging voltage is 4.21 )
const float battery_min = 3.20; //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(p_event->data.done.p_buffer, SAMPLES_IN_BUFFER));
for (i = 0; i < SAMPLES_IN_BUFFER; i++) {
avg_sample += p_event->data.done.p_buffer[i]; // take N samples in a row
}
avg_sample /= i; // average all the samples out
voltage = (static_cast<float>(avg_sample) * 2.04f) / (1024 / 3.0f);
voltage = roundf(voltage * 100) / 100;
percentRemaining = static_cast<int>(((voltage - battery_min) / (battery_max - battery_min)) * 100);
percentRemaining = std::max(percentRemaining, 0);
percentRemaining = std::min(percentRemaining, 100);
nrfx_saadc_uninit();
}
}
int Battery::PercentRemaining() {
return percentRemaining;
}
float Battery::Voltage() {
return voltage;
}
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