Posted on March 18, 2018 at 21:44Thanks for the suggestions.  The chip is an STM32F103C8T6.  All the signals (Power, I2C, and GPIO) look clean on a scope (I fitted extra decoupling capacitors to the chip's power pins a week or so back but it made no...

Posted on March 16, 2018 at 21:14After a few days of frustration, I've pretty much proved to myself there are bugs in the HAL I2C (using interrupt) routines.  I've an application that reads a MPU-6050 gyro via I2C.  There are also other simple edge-...