Rafael Rodrigues Obelheiro (firstname.lastname@example.org)
Wed, 3 Feb 1999 21:37:28 -0200 (EDT)
On Wed, 3 Feb 1999, Nicolas Souchu wrote:
> On Mon, Feb 01, 1999 at 08:48:20AM -0200, Rafael Rodrigues Obelheiro wrote:
> >On Sun, 31 Jan 1999, Andree Borrmann wrote:
> >> is there a standard for ecp 8bit nullmodem cables?
> >> How exactly are the status and control lines connected?
> >> If someone can answer these question I would volunteer to rewrite the plip
> >> driver to support 8bit modi.
> >I've been working on this stuff for a couple of weeks. I hope I'll be able
> >to deliver a working driver by the end of the month. So far, I've been
> >finding out several undocumented "features" of ECP (or, at least, of this
> >implementation of ECP), which is rather time-consuming. Right now, I have
> >a couple of programs that perform host-to-host communication in ECP mode,
> >but I'm still devising a suitable protocol (to control channel reversion)
> >so that a real PLIP-ECP driver can be written.
> Yeah! And what's your idea about negociation?
Actually, this is my term project in college; I'm gonna make it work
first, then I'll proceed to do negotiation (I know this is not the best
approach to do this, but my deadline is getting real close now). For a
"real" implementation, this is completely unacceptable, and I'm aware of
this; I'll polish it when time permits me to do so.
> >As for the wiring, I'm using
> > 100R
> > D0-D7 ------/\/\/\------ D0-D7
> > HostClk -----------------> PeriphClk
> > PeriphClk <----------------- HostClk
> > HostAck -----------------> PeriphAck
> > PeriphAck <----------------- HostAck
> >ReverseRequest ---+-------------> X-Flag
> > AckReverse <--|
> > X-Flag <-------------+--- ReverseRequest
> > |--> AckReverse
> > 1284 Active -----------------> PeriphRequest
> > PeriphRequest <----------------- 1284 Active
> I do not agree with your wiring :)
I already knew that :)
> I think, PeriphRequest should be connected to ReverseRequest and
> 1284 Active to X-Flag. Otherwise, byte mode handling is incompatible with
> IEEE1284 and you may not be able to handle ECP recovery either in a host to
> host transfer mechanism.
I'll think about your ideas very carefully, and peek at your code. More on
this subject to come soon. Anyway, as stated below, this is by no means a
definitive wiring :)
> >but this is still subject to change, since I've been experiencing some
> >tough problems.
> Let's Tim CC you our last mail about ECP. We aim at having something
> compatible between FreeBSD and Linux.
I totally agree with you (both).
-- Rafael Rodrigues Obelheiro email@example.com Rio Grande, RS, Brazil
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