3.3.1 Programming Issues

• Is clock to the CAN module enabled? Check for this if writes to CAN registers are not going through. Clock is enabled through a bit in the PCLKCRn register.
• Are 32-bit R/W operations used while accessing the eCAN registers? For an example, see the device-specific TRM.
• Comment all EDIS from your code until you get it to work. You could add it later. Many registers and bits are EALLOW protected and a write may not go through if EALLOW is not active.
• Try your code without interrupts first. Use polling instead. Once polling works, you can add interrupts later.
• If a specific mailbox is not working, have you attempted to use a different mailbox? Have the mailboxes been enabled in the CANME register and the mailbox direction correctly configured in the CANMD register?
• Was the MSGGID register initialized to zero, before the individual bits/Bit-fields were configured? Watch out for bits that may come up undefined upon reset.
• Do not use Acceptance Mask Filtering initially. Transmit the same MSGID. Filtering could be added later once it is confirmed there are no hardware issues with the bus.