TMS320F280049: CAN: Read multiple times from IF3 during one RX interrupt

Stefan W

Hi,

is it possible to read multiple times from IF3 during one RX interrupt? In my application it is possible, that there are already two message when I get into the RX interrupt for the first time.

I tried to read the IF3Upd-flag in a loop. At the end of each iteration all configured registers in IF3_OBS are read. This does not work. The IF3Upd-flag is only set once.

The next RX interrupt is triggered with the next message.

So I will always read the message before the current and will never get to the current.

What can I do?

Best regards,

Stefan W.

over 6 years ago

0 Baskaran Chidambaram over 6 years ago

TI__Genius 17370 points

IF3Upd-flag will be updated once for each object.

You may need to do DMA transfer from message RAM or ensure the ISR can handle the incoming data rate (so that you read fast and go to the current message).

Regards

Baskaran

0 Stefan W over 6 years ago in reply to Baskaran Chidambaram

Intellectual 280 points

Thanks for your reply.

I trigger a DMA transfer by reading the configured registers from IF3 to reenable it (in my case only the Mask).

But IF3 has no busy flag I could wait on. I think that is why the program does not enter the loop a second time.

Instead I will use IF1 or 2 to read the message. But I am still curious if there is a way to handle this with IF3.

0 Baskaran Chidambaram over 6 years ago in reply to Stefan W

TI__Genius 17370 points

CAN_IF3MCTL register has EoB field indicating whether current message is the last one or not.

Can you check if you can use it to read all the messages.

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TMS320F280049: CAN: Read multiple times from IF3 during one RX interrupt