Re: [PARPORT] newbie questions

From: Peter Keller (
Date: Sat Oct 21 2000 - 23:46:13 EDT

  • Next message: David&Beth: "[PARPORT] Port Reading"

    On Wed, Oct 18, 2000 at 12:00:22PM +0100, Tim Waugh wrote:
    > > However, I looked through ppdev.h and noticed that there isn't a clearly
    > > defined interface for me to tell the parport to read/write an address cycle
    > > or a data cycle. There is in parport.h, but it looks like I need to be in
    > > a kernel driver to use it correctly. Is that the case?
    > No, you just need to do something like this:
    > mode = IEEE1284_MODE_EPP | IEEE1284_ADDR;
    > ioctl (fd, PPNEGOT, mode);
    > ...
    > mode = IEEE1284_MODE_EPP | IEEE1284_DATA;
    > ioctl (fd, PPNEGOT, mode0;
    > ...
    > If you're already in EPP mode, all the 'negotiation' does is tell
    > parport to use address or data mode for future i/o operations.

    If I change the output mode of the parport to be in the data cycle context,
    what will the value of NADDRSTRB be during my data writes? And vice versa?

    I expect the strb line that I am not using to stay high while I'm dealing
    with the other mode. Is this a correct assumption?

    Thank you.


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