Ross Myers

MSCAN experts, please help.

Discussion created by Ross Myers on Nov 21, 2007
Latest reply on Nov 22, 2007 by Sten Siren
Hi All,
I'm getting a little frustrated here with what should be something so simple.
I am at the stage of testing the CAN circuit on a new product but I am not having much success.
I've given up on Rx'ing a CAN message, instead I thought I'd simply try to send something...well, I can send but there is something very odd happening.
Problem#1 - When I set the Tx Buffer up, IDR0, DLR, DSR0 etc it appears nothing is actually being moved in to the buffer. You can see in the Assembly window (in the attached screen shot), there has been data moved in to the DSR0 - DSR7 but it still shows as $AD on the memory trace.
Problem#2 - When it does put the message in the Tx Buffer (maybe it is filling with $AD as the memory dump shows?) once the message is in there the MSCAN is sending the same thing over and over very fast (I am not in a loop doing this either) and then it shows all sorts of Tx error flags are set. The meaning of which is not very clear in the documents as to what causes the flags to set.
Any help would be much appreciated.