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Update BatteryController.h with non-linear discharge curve

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hassless 2021-08-15 12:25:15 +02:00 committed by JF
parent 559b555d47
commit a67f401b30
2 changed files with 36 additions and 5 deletions
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40
src/components/battery/BatteryController.cpp
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@ -60,8 +60,6 @@ void Battery::SaadcInit() {
}
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) {
@ -77,10 +75,8 @@ void Battery::SaadcEventHandler(nrfx_saadc_evt_t const* p_event) {
uint8_t newPercent;
if (isFull) {
newPercent = 100;
} else if (voltage < battery_min) {
newPercent = 0;
} else {
newPercent = std::min((voltage - battery_min) * 100 / (battery_max - battery_min), isCharging ? 99 : 100);
newPercent = std::min(GetBatteryPercentageFromVoltage(voltage), static_cast<uint8_t>(isCharging ? 99 : 100));
}
if ((isPowerPresent && newPercent > percentRemaining) || (!isPowerPresent && newPercent < percentRemaining) || firstMeasurement) {
@ -97,3 +93,37 @@ void Battery::SaadcEventHandler(nrfx_saadc_evt_t const* p_event) {
void Battery::Register(Pinetime::System::SystemTask* systemTask) {
this->systemTask = systemTask;
}
uint8_t Battery::GetBatteryPercentageFromVoltage(uint16_t voltage) {
// The number of line segments used to approximate the battery discharge curve.
static const uint8_t LINE_SEGMENT_COUNT = 7;
// The voltages (mV) at the endpoints of the line segments. Any two consecutive
// values represent the start and end voltage of a line segment.
static const uint16_t voltageOffsets[LINE_SEGMENT_COUNT + 1] {4157, 4063, 3882, 3747, 3716, 3678, 3583, 3500};
// The battery percentages at the endpoints of the line segments. Note that last
// value is omitted: It is not needed because we only need the percentages at
// the start of each line segment.
static const float percentageOffsets[LINE_SEGMENT_COUNT] {100.000, 95.197, 70.429, 48.947, 35.158, 18.971, 5.801};
// The pre-calculated slopes (in battery percentage points per millivolt) of the
// line segments.
static const float percentageSlopes[LINE_SEGMENT_COUNT] {0.05109, 0.13684, 0.15913, 0.44481, 0.42595, 0.13863, 0.06989};
if (voltage >= voltageOffsets[0]) {
return 100;
}
if (voltage <= voltageOffsets[7]) {
return 0;
}
for (uint8_t i = 0; i < LINE_SEGMENT_COUNT; i++) {
if (voltage > voltageOffsets[i + 1]) {
return static_cast<uint8_t>(roundf(percentageOffsets[i] + percentageSlopes[i] * (voltage - voltageOffsets[i])));
}
}
return 0;
}

1
src/components/battery/BatteryController.h
View file

@ -49,6 +49,7 @@ namespace Pinetime {
void SaadcEventHandler(nrfx_saadc_evt_t const* p_event);
static void AdcCallbackStatic(nrfx_saadc_evt_t const* event);
static uint8_t GetBatteryPercentageFromVoltage(uint16_t voltage);
bool isReading = false;