Skip to content

tommag/ESP32_ADC_Calibration_tool

master
Switch branches/tags
Code

Latest commit

 

Git stats

Files

Permalink
Failed to load latest commit information.
Type
Name
Latest commit message
Commit time
doc
 
 
 
 
lib
 
 
src
 
 
 
 
 
 
 
 
 
 

ESP32 ADC calibration tool

This code is written to assist you in calibrating the ESP32 Analog to Digital converter. While newer chips are factory calibrated, older chips rely on a default VRef value and most of the time have poor ADC performance.

This tool is based on this forum post : https://esp32.com/viewtopic.php?t=8774#p36882 .

Disclaimer

Performing an ADC calibration involves burning fuses, which is an irreversible operation. Use this code at your own risk.

Setup

Open this project with PlatformIO and upload to a ESP32 board.

Usage

Open a serial console at 115200 bps on UART0. Then follow the instructions.

The workflow is the following :

  1. Apply 150mV to GPIO25 (ADC2) and GPIO34 (ADC1). It is advised to add a decoupling capacitor next to the pins.

  2. Apply 850mV to GPIO25 and GPIO34 when requested.

  3. Burn the calibration data into eFuse using espefuse.py tool and the values printed on the serial console.

Results

ADC error chart

For ADC1 the accuracy improved in the 0.2-2.5V range. Outside this range it seems that two point calibration is not used.

About

A small tool to assist in calibrating manually the ESP32 ADC

Topics

Resources

Stars

Watchers

Forks

Releases

No releases published

Packages

No packages published

Languages