I did try the Wir-library first, but it did not work. So I searched for a i2c-slave library as sayd in my first post. On arduino.cc I found the mentioned library, but in the meantime have switched to the latest version of Wire. Now everything works fine.

Hi,
I switched to the Wire-library which was updated recently, following a tip from @Koepel I got in
https://forum.arduino.cc/t/i2c-slave-st ... /1010793/7
Now it works in one direction. I will test the other direction sometime this week.
Thank you, Karl

Thank you for the tip, but it does not work for me. After changing the code I get: src/main.cpp:128:13: error: 'class TwoWireSlave' has no member named 'setPins' WireSlave.setPins(SDA_PIN, SCL_PIN); ^~~~~~~ src/main.cpp:130:33: error: no matching function for call to 'TwoWireSlave::begin(int)' WireS...

Hi, I want to build a large display with 4 7-segment digits. A master-ESP32 gets the data to display via MQTT and sends them via an i2c-bus to the digits, which each have a ESP32-slave. The slaves shall compile their i2c-address from 3 jumpers according to their position in the display. So I only ha...