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Original question:

TMS570LC4357: No "new data" flags are set

TMS570LC4357: Flexray example code transmit question

David Cardin
Prodigy 85 points
Part Number: TMS570LC4357

I am using the 6837.TMS570LS3137_FlexRay_Example  code provided by TI. I have only 2 nodes on the network. I am monitoring the bus traffic

with a logic analyzer.  The two boards come up and transmit the traffic shown in the first picture.  Each node alternately transmits and you can see the

message is received on the opposite node's Rx line.  This traffic repeats every 5.5 ms.  This traffic continues to occur even when the code on one node

is stopped with a breakpoint. I assume this is correct, and this traffic is for synchronization and driven by the state machine hardware.  Is this correct?

The short blue pulse on the very bottom trace marks the call to  Fr_TransmitTxLPdu after loading data into the WRDS array.  No data (except the sync

traffic) is ever transmitted onto the bus by either node.  I have NOT changed any of the buffer configuration from the example code. Can you offer some

insight as to why nothing is ever transmitted out on the wire?

Nodes Alternating Tx, top 3 traces belong to node 1, next 3 traces belong to node 2

Traffic pattern repeats every 5.5 ms.

Thank you,

David

  • 0
    TI__Guru**** 196776 points

    Hi David,

    David Cardin said:
    I assume this is correct, and this traffic is for synchronization and driven by the state machine hardware.  Is this correct?

    You are right.

    Two nodes should not transmit the frame simultaneously. How the waveform on the DM/DP flexray bus looks like?

    I need to find my flexray cards and try later. 

  • 0
    Prodigy 85 points

    Hi QJ Wang,

    The two nodes are NOT transmitting simultaneously. They are alternating. The problem is I never see any data being transmitted on the bus except the sync data between the two nodes.  I am using the example code provided by TI.  When the  Fr_TransmitTxLPdu(Fray_PST, write_buffer);  call is made I toggle a GPIO line. That is the blue trace (bottom trace) on the pictures above. The data for that transmit NEVER appears on the wire.  I believe the buffers are correctly configured. Can you provide some insight as to why the transmission is not occurring?

    Thank you

    David

  • 0 in reply to David Cardin
    TI__Guru**** 196776 points

    Hi David,

    Have you make the flexray communication work?