CAN receive interrupts

newguy · Joined: 24 Jun 2004 Posts: 1903

Think I know the answer, but just want to make sure....

If the pic's CAN transceiver's receive filters are set to accept all messages, how will the CAN receive interrupts behave? Assuming, of course, that both receive interrupts are enabled.

Will only one of the interrupts (either RX0 or RX1) see any "action", or will they alternate if one happens to be "full" when the next incoming message arrives?

iso9001 · Joined: 02 Dec 2003 Posts: 262

Since I don't use interrupts (polling all the way baby!) I don't know for sure but

From what I understand the interrupt is set when the message is loaded into the receive buffer from the message assembly area.

So, if you have accept all and RX0 full, when you get a message in you should get an int flag on CANRX1...

Are you using Mode0? I looked into using interrupts but then realized if I use mode1 on my most active node I have plenty of time for polling and other stuff even in a 100% utilization 1mbps bus.

You didn't say which chip you using (CAN, ECAN, SPI-based CAN) so you might not have a mode1 but personally I disliked the standard CAN that microchip had, too few buffers.... so if thats the case I'd look into a newer chip.