STM32F103 as I2C slave the PlatformIO way? (non-Arduino?)

[pilot]

As I have trouble using Arduino Wire library for slave;

STM32F108 as Slave won't work

This is an attempt to debug much bigger program: I recently moved it to STM32, and ran into this issue: The program never sees any packet addressed to it (address 0xB / d11) I DO see and decode packets incoming on the I2C bus (from the master), using a scope connected to SCL1/PB6/22 and SDA1/PB7/23 . I do NOT get to see them in the serial monitor. #include <Arduino.h> #include <Wire.h> long lastms; volatile int x = 0; volatile int y = 0; void receiveEvent(int howMany) { x = Wire.read();…

How do people solve I2C communications without Arduino?
are there some libraries or examples that works without Arduino framework, that are easy to implement?