#include "adc.h"

static uint32_t bat_voltage_mv;

void adc_setup(void) {
  rcc_periph_clock_enable(RCC_GPIOA);
  rcc_periph_clock_enable(RCC_ADC1);
  gpio_mode_setup(GPIOA, GPIO_MODE_ANALOG, GPIO_PUPD_NONE, GPIO3);
  adc_power_off(ADC1);
  adc_disable_scan_mode(ADC1);
  adc_set_sample_time_on_all_channels(ADC1, ADC_SMPR_SMP_480CYC);
  adc_set_continuous_conversion_mode(ADC1);

  uint8_t channel = 3;
  adc_set_regular_sequence(ADC1, 1, &channel);

  adc_power_on(ADC1);
  adc_start_conversion_regular(ADC1);
}

uint32_t adc_bat_voltage(void) {
  if (adc_get_flag(ADC1, ADC_SR_EOC)) {
    bat_voltage_mv = adc_read_regular(ADC1) * 3300 / 2048;
  }
  return bat_voltage_mv;
}