Tool/software:
Hi experts,
My customer is using MCAN for synchronization. They find there is jitter in the interrupt respond time.
They tested with 2 F280039C with same firmware. The 2 devices are connected to the same CAN bus, the frame on the bus would be received by the two devices, and triggers a CAN RX interrupt. They pull up an GPIO at the beginning of the ISR and pull it down at the end of the ISR.
In above picture, purple is device #1, top CAN RX and bottom is ISR GPIO. Blue is device #2, CAN RX and ISR GPIO.
As you can see, the CAN frame arrives device #1 and #2 almost at the same time, however, the ISR of #2 would starts ~1us later than #1.
Below is the condition of the test.
1. ISR run in RAM
2. No other interrupt on this device, the CAN RX is the only interrupt.
3. The jitter happens by chances, not every time.
Do you have any Idea what might cause the jitter?
Regards,
Hang.
