[PARPORT] RE: [patch] ieee1284 nibble mode

Andrea Arcangeli (andrea@e-mind.com)
Thu, 21 Jan 1999 12:12:40 +0100 (CET)

On Thu, 21 Jan 1999, Tim Waugh wrote:

> > > fudge delay needs to be longer to accommodate your printer as well.
> >
> > The error signal seems to be logical and _not_ timing related.
> Presumably you tried altering the delay before deducing that?

As just said yes.

> 2) Waiting for a timeout to find out that the device has finished should not
> be needed.

Ok, understood. Make tons of sense from a sane handshake point of view ;)

> > > > root@laser:/home/andrea# cat /dev/lp0
> >
> > It change when something change in the printer.
> The device ID changes? Interesting indeed. Which fields change - the
> manufacturer, command set, model number or device class? Personally I think
> that _any_ of those fields changing would be a neat trick.

I don't know which is the device ID field... I'll try something this

> > I know how to make the code working though ;).
> When you say that it works, is this with a timeout determining when to stop?

Yes. The timeout tell the driver when there's no more data available from
the printer. Ugly ;)

> > It has to become acceptable or I should do more reverse engeneering to
> > understand what the ERROR line means here and how could I make it working
> > here too
> I'll take the second option, if you don't mind.

What do you mean with `mind'?

> > But I don't have the real specs, so I couldn't know if the data-ready
> > indication was an hack as the Canon one. See things from my
> > point of view
> > ;).
> Did it look like a hack?

No at a first look, but I was not sure because my specs on the web told
everything of the nibble mode according to your code _except_ the ERROR
check to know when there's not data anymore. Maybe because the guy that
wrote the spces did reverse engeneering of the protocol of an Epson
printer? ;).

Please take a look at the specs I am looking at (just to see that I am not
crazy ;):

This for the nibble mode:


This for the negotiation:


Andrea Arcangeli

-- To unsubscribe, send mail to: linux-parport-request@torque.net --
-- with the single word "unsubscribe" in the body of the message. --

This archive was generated by hypermail 2.0b3 on Thu 21 Jan 1999 - 06:13:16 EST