54 lines
2.4 KiB
C++
54 lines
2.4 KiB
C++
#include "battery.h"
|
||
|
||
#ifdef FEATURE_BATTERY_MONITOR
|
||
#include <bluefruit.h>
|
||
|
||
extern BLEBas blebas;
|
||
|
||
// Battery ADC is kept permanently configured at 12-bit / AR_INTERNAL_3_0 to avoid
|
||
// the SAADC re-init cost of analogReference() changes, which blocks the CPU for
|
||
// several ms and causes BLE connection-interval violations (visible mouse freeze).
|
||
// PIN_VBAT_ENABLE is held LOW permanently once battery monitoring starts.
|
||
void initBatteryADC() {
|
||
pinMode(PIN_VBAT_ENABLE, OUTPUT); digitalWrite(PIN_VBAT_ENABLE, LOW);
|
||
pinMode(PIN_VBAT_READ, INPUT);
|
||
analogReference(AR_INTERNAL_3_0); analogReadResolution(12);
|
||
// Warm up with a few reads (no delay — just discard results)
|
||
for (int i=0; i<8; i++) analogRead(PIN_VBAT_READ);
|
||
}
|
||
|
||
float readBatteryVoltage() {
|
||
// 8 quick reads, no delay() calls, no analogReference() change
|
||
int32_t raw=0; for (int i=0; i<8; i++) raw += analogRead(PIN_VBAT_READ); raw /= 8;
|
||
// Seeed XIAO nRF52840 Sense: 1MΩ + 510kΩ voltage divider on VBAT.
|
||
// Theoretical ratio is 1510/510 = 2.961, but real resistor tolerances
|
||
// shift the actual ratio. Calibrated: 3.90V actual / 3.78V reported → ×1.0317.
|
||
return (raw / 4096.0f) * 3.0f * (1510.0f / 510.0f) * 1.0317f;
|
||
}
|
||
|
||
int batteryPercent(float v) {
|
||
return (int)constrain((v - BATT_EMPTY) / (BATT_FULL - BATT_EMPTY) * 100.f, 0, 100);
|
||
}
|
||
|
||
void updateBattery() {
|
||
float v = readBatteryVoltage(); int pct = batteryPercent(v);
|
||
bool chg = (digitalRead(PIN_CHG) == LOW);
|
||
ChargeStatus status = chg ? (pct >= 99 ? CHGSTAT_FULL : CHGSTAT_CHARGING) : CHGSTAT_DISCHARGING;
|
||
// Only write BLE Battery Service when connected — blebas.write() blocks on the
|
||
// SoftDevice ATT layer and causes 30-40ms loop stalls when called during advertising.
|
||
if (Bluefruit.connected()) blebas.write(pct);
|
||
lastChargeStatus = status;
|
||
#ifdef FEATURE_TELEMETRY
|
||
telem.chargeStatus = (uint8_t)status;
|
||
#endif
|
||
const char* st[] = {"discharging","charging","full"};
|
||
Serial.print("[BATT] "); Serial.print(v,2); Serial.print("V ");
|
||
Serial.print(pct); Serial.print("% "); Serial.println(st[status]);
|
||
// Critical battery alert — only blink when not connected to avoid blocking BLE scheduler.
|
||
// 6 × 160ms = 960ms hard block; skip during active connection.
|
||
if (status == CHGSTAT_DISCHARGING && v < BATT_CRITICAL && !Bluefruit.connected())
|
||
for (int i=0; i<6; i++) { digitalWrite(LED_RED,LOW); delay(80); digitalWrite(LED_RED,HIGH); delay(80); }
|
||
}
|
||
|
||
#endif // FEATURE_BATTERY_MONITOR
|