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TMS320F280025C: CAN BUS will not send messages unless in external loop back mode

david goodin
Intellectual 420 points

Part Number: TMS320F280025C
Other Parts Discussed in Thread: SYSCONFIG

I set up the CAN peripheral using SYSconfig. 500k, 2 object 1 transmit, one receive. I have a test message transmitting with each trasnition of the "life" LED about every second. If I enable external loop back, the message is transmitted as expected, and using a PEAK USB/CAN adapter, the PCAN application sees the correct 8 byte message and life is good...

until I turn off external loop back. Now, no test message is sent, the life LED is still blinking. The UART works and I can communicate with the board. board.c is the setup generated by sysconfig.

If I try to send a message to the board from PCAN, no interrupts are generated, I am stumped...

...help

  • 0
    TI__Mastermind 43150 points

    Hi David,

    Can we examine the contents of CAN_CTL, CAN_ES, CAN_ERRC, CAN_IPEN_21 and CAN_NDAT_21 in the register view?  This may lead us to what is going on in the CAN module.

    Thanks,

    Joseph

  • 0 in reply to Joseph Casuga
    Intellectual 420 points

    Thanks,

    turns out no matter that the MUX says “use gpio18 for CAN RX”, since that pin is also a crystal input, if you have crystal selected as clock source and NOT “single ended”, that take priority.

    once I changed the clock input to “SE”, everything sprang to life. 

    Now, if y’all would fix the SCI uart, this chip would be nearly perfect…