Hi Ingo,

Thank you for coming forward. I am not having any success in achieving a Can transmission in Normal mode. I have two 18f4580s connected together on 400mm of twisted pair and 120 ohm terminating resistors. The master is set to transmit only, the 'slave' to reply with received data byte values plus decimal one.

I have both configured to 125Khz data rate based on 16 Mhz xtals.
Using an oscilloscope monitoring the Can bus I can see activity. Both units output the same stream. A dominant 30uS pulse, followed by fifteen 10uS wide dominant pulses at 200uS intervals, this does not correspond to the data rate or the standard frame. I have checked my BRGCON settings against the microchip BRG calculator and everything is correct. After a restart, the respective 'transmissions' may appear synchronized, but can often overlap. Because of this I do not think either is properly responding to the prescence of the other. Runnning the receiving node in ICD The rx buffers are not accepting any data and rx buffer flags are never set. Equally the master -(tx only) never clears TXReq bit , Tx errors are flagged (PIE3 etc) . In short I am a little lost. Plenty indications of things going wrong, but no real indications as to the cause.

I have a nominal bit time of 8Tq, I read somewhere that increasing this to around 13 may help. Did not try this yet as I had more pressing things to attend to.

Hope this is not too confusing - trying to be concise.