Hi, What is different the configMAX_PRIORITIES and configKERNEL_INTERRUPT_PRIORITY? In Cortex_LM3Xxxxx demo, the FreeRTOSConfig.h defines configMAX_PRIORITIES = 5 and configKERNEL_INTERRUPT_PRIORITY = 255. Since the maximum priorities is only 5, why the kernel interrupt priority is 255? Thanks, Bill Yang

Again you are confusing task priority with interrupt priority. Task priorities are related to FreeRTOS and interrupt priorities are a characteristic of the hardware.  See http://www.freertos.org/a00109.html