ADC raw value steps - ESP32-C3

atouron
Posts: 6
Joined: Mon Sep 05, 2022 4:50 am

ADC raw value steps - ESP32-C3

Postby atouron » Mon Feb 06, 2023 12:58 am

I'm currently using the ADC Continuous Read Mode and have encountered an issue when trying to measure a signal. The issue is that for some reason, the raw ADC values retrieved from the 'adc_digi_read_bytes' function seems to STEP. This is more noticeable when trying to measure smaller values.

Some info of my setup:
Module: ESP32-C3-MINI
IDF: V4.4.2

ADC configuration:
Sampling frequency 10kHz
ADC Unit 1, Channel 2
Attenuation 11dB

Below are some screenshots of the signal going into the ADC pin (shown by oscilloscope) and values read back by ADC (printed out in MS Excel)

100mV 50Hz signal
Oscilloscope:
Image
Raw ADC:
Image

40mV 50Hz signal
Oscilloscope:
Image
Raw ADC:
Image

15mV 50Hz signal
Oscilloscope:
Image
Raw ADC:
Image

Any help to find the cause of the 'stepping' of the raw adc values would be greatly appreciated.

Thank you.

jrahat
Posts: 1
Joined: Wed Feb 15, 2023 3:23 am

Re: ADC raw value steps - ESP32-C3

Postby jrahat » Wed Feb 15, 2023 10:14 pm

Hi,
I have same issue.
Have you found fix?

MicroController
Posts: 1734
Joined: Mon Oct 17, 2022 7:38 pm
Location: Europe, Germany

Re: ADC raw value steps - ESP32-C3

Postby MicroController » Thu Feb 16, 2023 10:02 pm


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