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