Re: [PARPORT] ECP read - FIFO/DMA

From: Tim Waugh (twaugh@redhat.com)
Date: Fri Mar 10 2000 - 13:35:15 EST

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    On Fri, 10 Mar 2000, Richard Stover wrote:

    > Since I've been working on a device driver to handle a high speed
    > camera that will produce data at very high rates I've been looking at
    > issues like this. If you have a peripheral that does follow the ECP
    > standards you shouldn't have to loose any data. The way to stop data
    > is to negotiate from reverse to forward phase (from input to output).
    > When the host sets nReverseRequest (also called nInit high, the
    > pheripheral must tri-state its data bus. If the peripheral was in the
    > middle of a data transmission it must assume the data byte will be
    > discarded by the host and it stops all furthter transfers. You can
    > then read whatever is left in the fifo. nReverseRequest is bit 2 of
    > the device control register.

    Yes, that sounds like the answer.

    Tim.
    */

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