Hi Seeed-Jx,
I checked the LED and LED pin name and analogRead(PIN_VBAT) combination, but the 2/3 combination did not work correctly. In the worst case, the COM port was lost!
Below is the sketch I used to check.
#define LED LED_BUILTIN // default
//#define LED LEDR // OK : can read voltage and flush red LED
//#define LED LEDG // NG : COM port disappears and off green LED
//#define LED LEDB // OK : can read voltage and flush blue LED
//#define LED P0_26 // NG : can read voltage but always off red LED
//#define LED P0_30 // NG : COM port disappears and on green LED
//#define LED P0_6 // NG : can read voltage but on blue LED
const int analogInPin = PIN_VBAT;
int raw_bat = 0; // value read from the pot
int v_bat = 0;
uint8_t state = 0;
void setup() {
Serial.begin(9600);
pinMode(LED, OUTPUT);
pinMode(PIN_VBAT_ENABLE, OUTPUT);
digitalWrite(PIN_VBAT_ENABLE, LOW);
}
void loop() {
state = 1 - state;
digitalWrite(LED, state);
// read the analog in value:
raw_bat = analogRead(analogInPin);
v_bat = (raw_bat * 3 * 3300) / 1024;
Serial.print("raw = ");
Serial.print(raw_bat);
Serial.print(", V = ");
Serial.print(v_bat);
Serial.println("mV");
delay(500);
}