Wrong analogReadMilliVolts() in esp32s2

[fabianoriccardi]

#4072 # Hardware:
Board: ESP32-S2 Saola
Core Installation version: esp32s2 branch lates commit
IDE name: Arduino IDE

Description:

Hi, I was trying ESP32-S2 Saola breakout board, I would read analog values. I had used a variable lab bench power supply to test the ADC, but function analogReadMilliVolts() gives values 60% higher than the right value: i.e. if I set 1V, analogReadMilliVolts returns 1.6V. This behavior is constant all over the range (from 0 to 2.5V).

I think that the problem is about the fixed 13bit width in esp32-s2 while in esp32 ranges between 9 and 12.

https://docs.espressif.com/projects/esp-idf/en/latest/esp32s2/api-reference/peripherals/adc.html#_CPPv416adc_bits_width_t

Am I missing something?

Temporarily, I manage to use the following line to read input voltage:

int sensorValueRaw = analogRead(analogInPin);
int sensorValue = map(sensorValueRaw, 0, 8192, 0, 2600);

No other configuration were made to the ADC.

[stale]

[STALE_SET] This issue has been automatically marked as stale because it has not had recent activity. It will be closed in 14 days if no further activity occurs. Thank you for your contributions.

[stale]

[STALE_DEL] This stale issue has been automatically closed. Thank you for your contributions.