Hi:

define configKERNELINTERRUPTPRIORITY 255

define configMAXSYSCALLINTERRUPT_PRIORITY 191

define configLIBRARYKERNELINTERRUPT_PRIORITY 15

since STM32F217 and STM32F417 has same 4 bits prioirty in NVIC. could I set same configuration value for interrupt priority in FreeRTOSconf.h? and use following sample code to initialize NVICSetPriority( USART1IRQn, configLIBRARYKERNELINTERRUPTPRIORITY ); NVICEnableIRQ( USART1_IRQn );

Yes. If you are using the ST provided peripheral libraries then ensure to call NVICPriorityGroupConfig( NVICPriorityGroup_4 ); before starting the kernel. It is also recommended to use the latest FreeRTOS version (7.5.3) and define configASSERT http://www.freertos.org/a00110.html#configASSERT as that will catch common mis-configuratino problems. Regards.