[UART] 8250:RTS/CTS flow control issue.

From: moreau francis (francis_moreau2000_at_yahoo.fr)
Date: 03/15/05

  • Next message: Albert Cahalan: "Re: [PATCH][RFC] Make /proc/<pid> chmod'able" 
    Date:	Tue, 15 Mar 2005 17:05:54 +0100 (CET)
To: linux-kernel@vger.kernel.org

    I tried to use my serial port with rts/cts flow
    control enabled in order to transfer a data file
    between 2 DTE. The first one is a PC running Linux
    with a 8250 UART and the second one is a developement
    board running Linux with a particular UART (I wrote
    its driver based on 8250's one).

    Actually 8250 UARTs have rts/cts line but they're
    managed by software (and then called hw flow control
    !!!). Hence when my board's UART (which have a "true"
    hw flow control) asserts its RTS line, 8250's UART
    sends 8 bytes before stopping TX...
    Therefore board's UART fifo have been overrun because
    it has only 8 bytes for its fifo.

    Does it mean that we can't do any reliable flow
    controls with 8250 UART ? In that case a simple
    workaround would be to limit tx fifo to 1 byte...

    Thanks

         Francis

            

            
                    
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  • Next message: Albert Cahalan: "Re: [PATCH][RFC] Make /proc/<pid> chmod'able"

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