Is there a bug in the hardware I2C of STM32F103RCT6?
The STM32F103RCT6 , part of the STM32F1 series, does have known hardware issues with the I2C peripheral , especially in early silicon revisions. These issues are well-documented in the ST errata sheets . Known I2C Issues in STM32F103RCT6 From the STM32F103xC/D/E errata sheet , here are some notable I2C-related bugs : 1. I2C Busy Flag Stuck (BSY bit never cleared) Issue : If a communication is interrupted (e.g., by a reset or a glitch), the I2C peripheral can think the bus is still busy. Impact : The I2C_SR2.BSY bit stays high indefinitely, preventing further communication. Workaround : You must manually reset the I2C peripheral and reinitialize it . 2. Failure to Detect Stop Condition Issue : Under some conditions, the STOP condition is not correctly detected by the I2C hardware. Impact : The I2C peripheral might hang or misbehave after repeated communications. Workaround : Often handled by carefully placing delays and confirming the STOP bit in s...