toit-axp192-battery-reporter/axp192-battery-voltage.toit

import gpio
import i2c

// https://github.com/toitware/toit-axp192/blob/v1.0.1/src/axp192.toit
import axp192

main:
  led_pin := gpio.Pin 10 --output
  led_pin.set 0
  sleep --ms=100
  i2c_bus := i2c.Bus
    --sda=gpio.Pin 21
    --scl=gpio.Pin 22
  axp192_device := i2c_bus.device 0x34
  axp192.set_bits axp192_device axp192.ADC_ENABLE_SETTING_REGISTER_1 axp192.ADC_ENABLE_BATTERY_VOLTAGE
  // https://github.com/m5stack/M5StickC/blob/b4c4b15d4608472948af069afe8081e218296b06/src/AXP192.cpp#L354
  battery_voltage := (
    ((axp192_device.registers.read_u8 0x78) << 4) \
     + (axp192_device.registers.read_u8 0x79) \
    ) * 1.1 / 1000
  print "battery $(%.03f battery_voltage)V"