Re: [PARPORT] data rates and interrupt frequency of parport

From: Dave Strauss (
Date: Mon Oct 29 2001 - 09:15:16 EST

  • Next message: Dmitri Katchalov: "RE: [PARPORT] data rates and interrupt frequency of parport"

    On Sun, 28 Oct 2001 22:30:36 +0000, Tim Waugh <> wrote:
    > On Sun, Oct 28, 2001 at 07:34:39PM +0000, matt wrote:
    > > I've found various information saying that my parallel port
    > > should support data rates at up to 2MB/s. I think that this
    > > must be DMA and hardware helped - so what is a rate that
    > > I could expect through 1 pins, with the minimum latency
    > > (ie no DMA or buffering)?
    > Yes, this speed is what the ECP hardware can do I expect, and so it's
    > no good to you when you aren't doing ECP transfers.
    > Are you using a PCI parallel port card? You might find that you get
    > lower latency that way, since ISA reads are quite slow.
    > Tim.
    > */

    You should also be able to handle higher data rates if you use
    the FIFO and possibly DMA. I've been able to get upwards of
    500kBytes/sec transmitting data, so I suspect you should be able to
    get something similar when receiving. Since the FIFO is usually
    16 bytes deep, even without DMA you should be able to increase the
    latency you can tolerate by up to 16-fold.

    -- Dave Strauss

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