time_temperature_display/src/battery.h

#pragma once

#include <Arduino.h>

// 18650 battery monitoring, read through the onboard divider on ADC1_CH3.
//
// The divider sits on the battery node, downstream of the charger, so there is
// no way to tell "charging" from "full" here — only the cell voltage is
// reported. See CLAUDE.md.
namespace battery {

void begin();

// Samples the divider if BATTERY_READ_MS has elapsed. Call from loop().
void loop();

// Forces a reading now.
void sample();

// True once a plausible reading has been taken. False on a board with no cell
// fitted and no sensible voltage present.
bool hasReading();

// Cell voltage in volts.
float volts();

// Remaining charge, 0-100, from a lithium-ion discharge curve.
uint8_t percent();

}  // namespace battery