I have a STM32F4 UART interrupt which sends a queue msg as soon as data is ready. When UART interrupt priority was 0, I had assertion fail. The text describes the failure (thanks for the comment near the assertion, very helpful) , and changing the priority to 15 ( was 0) solves the problem. However I am not sure I fully understand what I did. The configMAXSYSCALLINTERRUPT_PRIORITY equals 0x50 ( which I don’t get as the interrupt priority can be 0 – 15). Why when the UART priority is 0 (highest) it does not work? What should be the correct value of the UART interrupt priority for safe operation? Thanks Johanan

did you see this page already http://www.freertos.org/RTOS-Cortex-M3-M4.html ?

Now I did 🙂 Thanks