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Flexray TBF to Message RAM

Sindhu Krishna
Expert 1350 points
Other Parts Discussed in Thread: TMS570LS20216

Hello TI !

I have a question regarding the Flexray Module implemented in TMS570LS20216. The message transmission from Host to the FR pins happens through TBF. Is there any source that well explains the frame transmisssion from Rx Pin to Message RAM and from Message RAM to Tx Pin? I have this doubt as I'm unable to understand how frames pass into TBF and IBF/OBF to reach Message RAM.

Thanks in advance !

  • 0
    TI__Expert 4580 points
    Hello:

    Sorry for the late response. I'm forwarding your question to one of our experts. We will get back to you soon.

    Regards.
  • 0 in reply to Enrique Lizarraga
    TI__Guru**** 186246 points

    Hello,

    Please find the the flexray sample code at:

    http://processors.wiki.ti.com/index.php/TMS570_MDK_Kit

    The code contains both TX and RX portion. 

    Fr_TransmitTxLPd() function writes the message buffer numbers to IBRH. With this write operation, IBF host and IBF shadow are swapped, IBSYS is set. The message handler starts to transfer the contents (WRHS[3:1], and WRDS[64:1]) of IBF shadow to the message buffer in the message RAM.

    If a valid payload was stored in the data section of a message buffer (checking NDAT registers in  transmit_check_node() function), Fr_ReceiveRxLPdu() function enables either data transfer or header transfer from the message RAM to OBF, and makes OBF transfer request. The data in message RAM will be transferred to RDDS[64:1]. transmit_check_node() function reads the data.

    TBF (transient buffer) is used to buffer the data for transfer between the flexray channel protocol controller and the message RAM. TBF is built up as a double buffer, able to store 2 flexray messages. One buffer is assigned to flexray protocol controller, and the other is assigned to the message handler. The message handler transfers data between the TBF and message RAM.

    Regards,

    QJ