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CCS/TM4C123GH6PM: Need clarification for the WRNRD bit of the CANIFnCMSK register.

Amarendra Mishra
Prodigy 70 points
Part Number: TM4C123GH6PM

Tool/software: Code Composer Studio

Hello ,

I found it very confusing that in the CAN IFn Command Mask (CANIFnCMSK) register , for the WRNRD bit, it is written that setting this bit will transfer data from CANIFn registers into the message object
whereas for the DATAA bit , it is written that setting WRNRD bit will transfer data from message object into the CANIFn register. Also, please explain what the datasheet refers to as the "message object". Does this mean the message object created by the CPU or the one created by us?

  • 0
    TI__Guru 72500 points

    The description of the DATAA and DATAB bits is incorrect. The correct description is:

    If WRNRD is set, transfer data bytes 4-7 in CANIFnDA1 and CANIFnDA2 to the message object.

    If WRNRD is clear, transfer data bytes 4-7 in message object to CANIFnDA1 and CANIFnDA2

    A "message object" is a CAN mailbox. This device supports up to  32 message objects. A message object can be a CAN frame to be transmitted or a place to put a CAN frame that is received.