Wifi 32 kit ADC wild readings

#1

I have been working with a WiFi kit 32 and having an odd issue with ADC-1. I read a voltage on one ADC pin and that reading is perfectly accurate. I then do some math on that value and output a value to an MCP4725 I2C 12-bit DAC card. The output of that DAC goes out to another device (a voltmeter for now) and back to another ADC-1 pin on the WIFI KIT 32. The problem is that while the DAC output reads exactly correctly on the voltmeter, the ADC shows a way different value. There s mom linearity to it. Goes up and down correctly but the value reason the ADC is simply way off but not by any linear ratio or offset.

Any ideas?

#2

ESP32 ADC has a non-linearity problem
https://www.esp32.com/viewtopic.php?t=2881

#3

Alexey,

Thanks for sending me this. My problem is not simply non-linear it, the readings are way off when I read back the DAC card output. The other input is just fine.

Pete