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LAUNCHXL2-TMS57012: CAN protocol

Dina Bino
Prodigy 100 points

Part Number: LAUNCHXL2-TMS57012

Hi,

I am new to CAN protocol, I am using Hercules launch pad.

I successfully test the can module in loop back.
when connecting to transceiver every thing works fine between CAN1,CAN2,CAN3  messages are sent and received as it should be .

my question is  I was trying to test the connection with the transceiver similar to  loop back , but i was unable to do so .

( CAN 1 message box 1 as TX , message box 2 as RX  with same ID for both ) , i can see the signal on the bus, and the interrupt is hit. but the data is not received if it is from same module?

Thanks a lot.

  • 0
    TI__Guru**** 201546 points

    Hello,

    Most CAN controllers support test modes: loopback modes and silent mode. Those modes are mainly intended for production tests and self test. In loopback mode, the RX pin is ignored.

    Some CAN transceivers also support loopback mode which redirects the transmit data through logic to the receive data to create an internal loopback. This mode allows the host controller to input and read back a bit sequence or CAN messages to perform diagnostic routines without disturbing the CAN bus. Please check the datasheet of the CAN transceiver how to put the transceiver to loopback mode.

    For CAN regular communication, at least two nodes are required. A CAN node cann't ACK itself, and will not receive its own message.

  • 0 in reply to QJ Wang
    Prodigy 100 points

    Thanks alot for clarifying.