On Mon, 9 Apr 2012, Sebastian Kuzminsky wrote:
> Date: Mon, 9 Apr 2012 17:01:41 -0600
> From: Sebastian Kuzminsky <[email protected]>
> Reply-To: "Enhanced Machine Controller (EMC)"
> <[email protected]>
> To: "Enhanced Machine Controller (EMC)" <[email protected]>
> Subject: Re: [Emc-users] Hal_parport and EPP
>
> EPP mode is a completely different way of using the pins of the parport than
> the regular SPP mode. In SPP, you have programmatic control over the values
> on the output pins, and you can read all the input pins.
>
> In EPP, those pins are driven by an additional piece of logic in the parport
> controller. The driver software asks the EPP controller to read and write
> addresses on the EPP bus, and the controller twiddles the pins to implement
> the software's request, according to the datalink protocol described by the
> EPP spec. So in order to do anything interesting/useful with the EPP port,
> you need a second driver that knows what registers to read and write on the
> device on the EPP bus.
>
> Simply switching the port to EPP mode doesn't accomplish anything.
>
> Maybe i'm missing something in your request?
>
>
>
>
It does accomplish something subtle with some parallel port cards EPP mode is
compatible with SPP mode but on some parallel port cards it changes the drive
mode of some control output pins to Push-Pull instead of open drain with a
pullup.
Peter Wallace
Mesa Electronics
(\__/)
(='.'=) This is Bunny. Copy and paste bunny into your
(")_(") signature to help him gain world domination.
------------------------------------------------------------------------------
For Developers, A Lot Can Happen In A Second.
Boundary is the first to Know...and Tell You.
Monitor Your Applications in Ultra-Fine Resolution. Try it FREE!
http://p.sf.net/sfu/Boundary-d2dvs2
_______________________________________________
Emc-users mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/emc-users
