How does FDCAN time stamping work exactly on the STM32H7 ?

[K M]

The FDCAN module generates timestamps for sent and received messages, and you can configure it to use TIM3 as the source. Unfortunately, the documentation is rather thin, so I am left with a few questions:

• Do TIM3 and FDCAN need to run from the same clock or are they synchronized?
• What triggers the timestamp? I suspect this is the SOF bit, and it is sampled once every normal time quantum, so that the trigger resolution is one time quantum
• One probably should not use the timer overflow flag in the CAN module when using TIM3, but check directly in the timer?
• Is there a recommended sequence to get FDCAN time quanta and TIM3 aligned, or should we just run TIM3 with a higher frequency?

[ppedro]

Hello,

can anybody answer the above questions? I dont find any information on how to configure using external CLK source for FDCAN RX timestamp (FDCAN_TIMESTAMP_EXTERNAL). Any advises are appreciated.

Thanx.

Best regards,

peter

[pravee123]

Hello brother 

I have one doubt im doing with rx timestamping I properly configured with 8 prescalar and freq is 64MHZ as per this my wraparound callback have to execute every 8millisec but it is executing for every 1.2sec I used internal rx time stamp fdcan Can please suggest me where I'm doing wrong