topic Re: Help K64FN1MDVLL12 BASEPRI Register Function does not work in Kinetis Microcontrollers

Help K64FN1MDVLL12 BASEPRI Register Function does not work

runningostrich — Mon, 13 Sep 2021 03:36:31 GMT

FreeRtos function vPortEnterCritical Assert stuck，

FreeRTOSConfig.h configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY Set 1

BASEPRI Register VALUE

this moment VECTACTIVE Register Value 3

Why?

freeRtos critical Function does not work

Tell me what should i do？

Re: Help K64FN1MDVLL12 BASEPRI Register Function does not work

danielchen — Fri, 01 Oct 2021 01:56:59 GMT

Hi @runningostrich :

Please note that the BASEPRI will be configured to configMAX_SYSCALL_INTERRUPT_PRIORITY only if task enter into critical section. and BASEPRI will be reconfigured to 0 if task exit critical section.

You can trace the BASEPRI register after below line is hit.

taskENTER_CRITICAL();

Regards

Daniel

Re: Help K64FN1MDVLL12 BASEPRI Register Function does not work

ErichStyger — Sat, 02 Oct 2021 07:36:28 GMT

Hi @runningostrich ,

I highly recommend to get familiar with the ARM Cortex interrupt system in combination with FreeRTOS, an article series I wrote a while back:

https://mcuoneclipse.com/2016/08/14/arm-cortex-m-interrupts-and-freertos-part-1/

https://mcuoneclipse.com/2016/08/20/arm-cortex-m-interrupts-and-freertos-part-2/

https://mcuoneclipse.com/2016/08/28/arm-cortex-m-interrupts-and-freertos-part-3/

The assertion you hit is because you are calling vPortEnterCritical() from an interrupt context which is not allowed, hence the assertion. You need to check the call chain in the debugger to see from where this is coming from. BASEPRI/configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY is used for something different: separating the interrupts into 'RTOS-ones' from 'non-RTOS' ones. I would question why you would set the BASEPRI to 1 as this does not leave you much moving space for interrupt prioritites, but this is yet another discussion. For the complete picture, see above articles.

I hope this helps,

Erich