CAN receive different IDs in one mailbox

Chris,

Yes our can module allows to use mask to receive multiple IDs in the same mailbox.
Have you look to the CAN Chapter in the Technical Reference Manual for RM48?

Here is the TRM: http://www.ti.com/lit/ug/spnu503b/spnu503b.pdf

Hi Jean-Marc

I think I'm just understanding this incorrectly - is this something that can be done with the HALCoGen configuration (aka do I just leave the ID field blank?) and adjust my message ID bit mask accordingly?  I've become pretty familiar with this chapter but I'm still not sure how to do this exactly though to be entirely honest, I haven't changed the bitmask on the ID.

What I'm trying to do is leave one mailbox (box 64) open as a wildcard catch all.

Chris

Hi Chris,

In order to use identifier masking, UMask must be set for the according message object.

If identifier masking is disabled (UMask = 0), all identifier bits of a received CAN message must
match the identifier bitfield ID[28:0] for extended identifiers resp. ID[28:18] for standard identifiers.

If identifier masking is enabled (UMask = 1), Msk[28:0] bitfield defines which identifier bits
of a received CAN message must match the according bits of the identifier bitfield ID[28:0]. For
standard identifiers only Msk[28:18] are relevant, bits Msk[17:0] have no functionality.

Examples for extended identifiers:

UMask = 1 and all bits of Msk[28:0] are set to 1: all identifier bits must match identifier bitfield ID[28:0] (same as if UMask = 0).

UMask = 1 and all bits of Msk[28:0] are set to 0: no identifier bit must match identifier bitfield ID[28:0] (all CAN messages will be received).

UMask = 1 and Msk[28:0] is set to 0x7: bits 0, 1 and 2 of the identifier must match identifier bitfield ID[2:0], bits 3 to 28 of the identifier are don't care.

Best Regards,
Peter Steffan

Thank you Peter - it was really confusing in the beginning since our HALCoGen project was set up where it looked like it was the reverse of what you were saying (but since they're ANDed together it's the same effect)

Chris

So now that I'm receiving messages into the correct message boxes, (for this case say (0x780 & 0x080) into bin 62) I receive the messages when I want them but I can't figure out how to get the ID of the actual message on the wire.  I tried copying the arbitration register when the data was gathered from the message box but all I got was the ID of my thing that gets ANDed (what's set in HALCoGen)

Hi Peter

After doing what you'd suggested, I can't seem to get the exact ID of the message that came across the wire.  It filters into the right bin but whenever I try to get the ID, using the interface registers, I pull up the ID against which I had masked the message box.  Am I looking in the wrong place?

Thank you

Chris

Thank you very much Peter - I didn't realize I had to OR the bit on to grab the arbitration register.