What better port to read the battery voltage, with a resistive divider, on the heltec esp32 wifi kit oled board. Examples are required arduino.
Thank you advance
I think any analog pins can be used as ADC input (green label in pinout diagram).
What’s the problem you have? Can you provide some more details?
Anyway, two things you need attention:
The ADC maximum input voltage ≤ 2.5V, don’t over that value, or the ADC converter will be broken.
If the input voltage is already bigger than 2.5V, you need to have such a voltage dividing circuit:
The value of R10 and R12 may need change to fit your needs.