Re: [PARPORT] Example Code

From: Peter Ryser (
Date: Tue Apr 03 2001 - 18:25:10 EDT

  • Next message: Philip Blundell: "Re: [PARPORT] Example Code"

    I'm working on implementing different options and trying to find out
    what the impact on the performance is.

    A really bad (say hurried) implementation of (1) ioctl(fd, PPSPEW,
    buffer, len) gave me 50% performance gain over (2) for(;len>0;ioctl(fd,
    PPWDATA, buffer++), len--).

    Earlier I used (3) ioperm() and outb(). This was about twice as fast as (1).

    As soon as I know more, I'll let you know.

    I'm also thinking whether there is no easy solution to add handshaking
    to such simple devices. For serial ports you could just connect two pins
    and have "hardware handshaking". Is this also possible for parallel
    ports (if yes, for which modes [ECP with DMA would be nice])?

    - Peter

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