MPC5748G CAN FD trace

[JirikP]

Hi, 

we are trying to implement multi CAN FD tracer. Is it possible to use Message buffer or any other option to receive all CAN FD messages without knowing their IDs?

Thanks

Regards Jiri

[JirikP]

Ok, thank you for your fast answer.

We are worried that when we receive one msg to MB that managing of the interupt and data would take too long and we would loose msgs in between. Is is possible to "daisy chain" the MBs or us DMA?

[PetrS]

Hi,

yes, this could happen, but it is already application problem, to read out MB in time.
DMA is only supported over RXFIFO, but RXFIFO cannot be used if CANFD is enabled.
You have option to use reception queue (MCR[IRMQ] set) by programming more than one MB with the same ID, received frame will be stored into first free-to-receive MB. Again refer to Matching process chapter.

BR, Petr

[PetrS]

Hi,

yes, it is possible. Use Mask acceptance register for it. If cleared incoming ID is don't care. Note by default IDE bit is always checked, but if CTRL2[EACEN] is set, the comparison of both Rx Mailbox filter’s IDE and RTR bit is enabled with their corresponding bits within the incoming frame and Mask bits do apply.
For more info refer to Matching process chapter of the RM and description of RXMGMASK and RXIMRx registers.

BR, Petr