Many Thanks! You were right. The repeated initialization makes problems. I wouldn't have thought of that. Boarchuz, you are my hero! For posterity... I solved the problem like this. If there are better solutions, they are very welcome! #include <Arduino.h> #include <SPI.h> #include <stdio.h> #includ...

Hello, everyone I'm working on a project to read an I2C sensor with an ESP32 in battery mode. For this, I want to use the I2C bus with the ULP Coprocessor in the deep sleep mode. This should be possible and is even advertised: "The Ultra Low Power (ULP) coprocessor is a simple finite state machine (...