APM32F4 priority bits

Smoke666

Hello evreone! I try to port my stm32f4 project to APM34F4 and maybe finded error in apm32f4xx_misc.h. Trouble in NVIC_PRIORITY_GROUP_T. It’s defined like NVIC_PRIORITY_GROUP_0 = 0×700 and etc. But priority group can be 0 to 7… Of cause when i call NVIC_SetPriorityGrouping original define of NVIC_PRIORITY_GROUP don’t work and after this, all calls of NVIC_EnableIRQRequest set all enterupt priority to 0. A it’s “nice”, that configASSERT( x ) blocked in FreeRTOS example, but all calls FreeRTOS function xxxfromISR finich by HARD_FALUL, case priority of all interuprt in system is 0. And now i have question is how many priority bits realy in APM32F405? Cose if i use original FreeRTOSConfig from 1.0.4 pack, when #define configPRIO_BITS 4, it’s catch by configASSERT. But i look to Keil’s FreeRTOS config from APM32F4 pack and see that configPRIO_BITS = 3. And it seems, than it’s works.

Fane#14

Hi,

The older version of APM32F4 only support 3 priority bits, and the lateset version can support 4-bits just like stm32f4.
STM32F4&APM32F4(Latest version like C1)——NVIC_IPRx->bits[7:4] is R/W
APM32F4(older version like A2/A3) NVIC_IPRx->bits[7:5] is R/W
We suggest to use the latest version(C1).

If you need to use with FreeRTOS on APM32F4(A2/A3 version), we suggest to
a. config NVIC_PRIORITY_GROUP_3 which support 8*Group priorities. And then you don’t need to care about the subpriority.
b. Set configPRIO_BITS = 3, just like you already done.

2.“…when #define configPRIO_BITS 4, it’s catch by configASSERT”
——You can just comment the “configASSERT” then no assert error. It also relate to the NVIC difference mentioned above.