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TMS320F28035: Garbage value in CAN

Madhu Kiran
Prodigy 90 points
Part Number: TMS320F28035


Tool/software:

Hello team,

We are using TMS320F28035 controller and using CAN for communication.

From Mail box 18 we receive the data and that data we store in external memory. But we are seeing some corrupt data in the external memory.

Upon debugging it is observed that even without any CAN frames being sent, ECanaMboxes.MBOX18.MDL.all and ECanaMboxes.MBOX18.MDH.all registers are filled with some data and that is getting transferred to external memory.

What could be the reason for this garbage values in MBOX data and how can we resolve this issue?

Thanks & regrads,

Madhu P

  • 0
    TI__Guru**** 198996 points

    Hi Madhu,

    The data registers (MDL and MDH) are used for transmitting data or received data. If a received message matches one or more than one valid message objects, it is stored into the one with the lowest message number, and the NewDat bit of this message object is set. If the RxIE bit is set, the Interrupt pointing to this message object will be generated. The CPU can read the received message using IFx interface registers and will save the payload into MDL and MDH registers.

    So the MDL and MDH should contain the new received data. The old data in MDL and MDH is overwritten. 

    Madhu Kiran said:
    Upon debugging it is observed that even without any CAN frames being sent, ECanaMboxes.MBOX18.MDL.all and ECanaMboxes.MBOX18.MDH.all registers are filled with some data and that is getting transferred to external memory.

    If there is no received data (NewDat is 0), the data in MDL and MDH is useless, and should not be used.