i.MX ProcessorsのトピックRe: i.MX8QM Cortex-M FLEXCAN FreeRTOS

i.MX8QM Cortex-M FLEXCAN FreeRTOS

io — Thu, 25 Sep 2025 15:09:50 GMT

Hello,
I’m working with i.MX8QM Cortex-M4 running FreeRTOS.
I use the NXP FlexCAN driver with interrupt callback. Inside the callback I try to call xSemaphoreGiveFromISR(), but the program always hangs/stuck at that point.

I already tried changing interrupt priority and checked FreeRTOS config, but still same result.
Does anyone have a simple example how to use FlexCAN with FreeRTOS task (semaphore or task notify) on i.MX8QM?

Here is my main program.
https://pastebin.com/BrhXQC1w

Thanks.

Re: i.MX8QM Cortex-M FLEXCAN FreeRTOS

Bio_TICFSL — Mon, 29 Sep 2025 14:14:13 GMT

Hello,

Please check:

https://community.nxp.com/t5/i-MX-Processors-Knowledge-Base/iMX8QM-FLEXCAN-enable-and-test-case-on-A-core/ta-p/1349003

https://community.nxp.com/t5/i-MX-Processors/How-to-read-from-CAN-through-M4/m-p/1695836

Regards

Re: i.MX8QM Cortex-M FLEXCAN FreeRTOS

io — Tue, 30 Sep 2025 11:52:28 GMT

Just wanna share for anyone who may need it.

The problem was just the interrupt setup. I wrongly set the NVIC Priority
NVIC_SetPriority(DMA_FLEXCAN0_INT_IRQn, 3); which should be NVIC_SetPriority(IRQSTEER_4_IRQn, 3);

The FLEXCAN0 interrupt was connected to IRQSTEER_4_IRQn. Because the interrupt priority was wrongly set, it defaulted to a high priority (maybe 0). Then when calling xSemaphoreGiveFromISR() inside isr flexcan_callback, it causing the portASSERT_IF_INTERRUPT_PRIORITY_INVALID() failure and the program to stuck there.

Ref:
https://community.nxp.com/t5/i-MX-Processors/imx8qm-IRQSTEER-interrupt-mapping/m-p/1067519/highlight/true#M156853

https://www.freertos.org/Documentation/02-Kernel/03-Supported-devices/04-Demos/ARM-Cortex/RTOS-Cortex-M3-M4

Regards,