This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

C665x uPP receive operation without using START signal

Guru 10570 points

Hello,

I have a question about uPP operation.

I would like to use uPP as :
- ChA is receive mode (UPCTL->MODE=2)
- START signal is disabled (UPICR->STARTA=0)
- ENABLE signal is enabled (UPICR->ENAA=0)
- BCNT=10, LNCNT=2 (Totally 20bytes)

In this condition, my understanding is :
- ChA ignores START signal.
- ChA honors only ENABLE signal.
- uPP can receive as multi-line data when 20Byte of data is transmitted by other side.

Is my understanding correct?
(I am wondering if uPP can receive multi-line data when the START signal is disabled.)

Best regards, RY

  • Hello,
    I would like to tell you intention of my question.

    I observed the START signal asserted by each lines in uPP transmit mode.
    I am understanding it's uPP spec from UG.

    On the other hand,
    I am wondering if uPP needs to be provided START signal by each lines in uPP receive mode.
    Especially, I intend Not use START signal. Is it able to receive multi-line data?

    Best regards, RY

  • Hello RY,

    As described in section 2.5.3 START Signal in Keystone uPP user guide (SPRUHG9),

    In Transmit mode, START is an output signal and is always driven; In Receive mode, START is an input signal and may be disabled using the STARTx bit in UPICR.

    So the uPP need not to be provided START signal in receive mode. I believe the uPP will receive multi-line data without START signal.

    You can also see the required signals for receive mode in Table 2-5 Required Signals for Various Modes in user guide.

    http://www.ti.com/lit/ug/spruhg9/spruhg9.pdf

    Regards,

    Senthil

  • Senthil-san,

    Thanks for your comment!

    I checked it up on EVM. and, I could receive multi-line data without START signal in uPP receive mode.
    It is assumed proper operation in uPP by you. Right?

    I need to confirm what it's NOT illegal usage.
    Please give back your comment.

    Best regards, RY

  • Hello RY,

    Thanks for your update.

    As specified in the table 2.5 in user guide, the START signal is not mandatory for receive mode of operation.

    Receiving multi-line data without START signal is a proper operation in uPP receive mode and its NOT illegal usage.

    Regards,

    Senthil