Merge 1c30fb44e8 into 5f3b7f25d0

variants/heltec_v4/HeltecV4Board.cpp

@@ -62,18 +62,19 @@ void HeltecV4Board::begin() {
   }
 
   uint16_t HeltecV4Board::getBattMilliVolts()  {
-    analogReadResolution(10);
+    analogReadResolution(12);
+    analogSetPinAttenuation(PIN_VBAT_READ, ADC_2_5db);  // divider puts pin at 0.61-0.86V so this attenuation should cover it with some room to spare
     digitalWrite(PIN_ADC_CTRL, HIGH);
     delay(10);
-    uint32_t raw = 0;
+    uint32_t raw_mv = 0;
     for (int i = 0; i < 8; i++) {
-      raw += analogRead(PIN_VBAT_READ);
+      raw_mv += analogReadMilliVolts(PIN_VBAT_READ);
     }
-    raw = raw / 8;
+    raw_mv /= 8;
 
     digitalWrite(PIN_ADC_CTRL, LOW);
 
-    return (adc_mult * (3.3 / 1024.0) * raw) * 1000;
+    return adc_mult * raw_mv;
   }
 
   const char* HeltecV4Board::getManufacturerName() const {

variants/heltec_v4/HeltecV4Board.h

@@ -7,7 +7,7 @@
 #include "LoRaFEMControl.h"
 
 #ifndef ADC_MULTIPLIER
-  #define ADC_MULTIPLIER 5.42
+  #define ADC_MULTIPLIER 4.9  // (R1+R2)/R2 = (390k+100k)/100k
 #endif
 
 class HeltecV4Board : public ESP32Board {