[Linux-parport] Parport signals stability with SiS chipset

[tdlt at cecm.usp.br]

	I do not know how to frob the data pins, but only the control
	pins through ppdev.

	I do not believe this is the problem because the problem occurs
	even when I send only one byte to the data pins.

	Example:

	data pins: 00011001
	byte sent to data pins: 11111111
	data pins for a few microseconds: 11111111
	data pins after that few microseconds: 000110001

	After the boot proccess, the data pins is something as 00011001
	(I will confirm the pins state), but I don't know why.

	
On Wed, Mar 17, 2004 at 05:29:45PM -0800, Nate Jenkins wrote:
> 
> I was under the impression that when you try to write another byte that the
> voltage would drop.  I have never used frobbing but I thought that if you
> frobbed that only the specific pins that needed to change would do so, while
> the ones not needing to change would maintain voltage.
> 
> Nate
> 
> "Maybe I read the wrong fictional novel?"
> 
> 
> ----- Original Message ----- 
> From: <tdlt at cecm.usp.br>
> To: "Linux Parallel Port Development" <linux-parport at lists.infradead.org>
> Sent: Wednesday, March 17, 2004 4:00 PM
> Subject: Re: [Linux-parport] Parport signals stability with SiS chipset
> 
> 
> > On Wed, Mar 17, 2004 at 10:44:22AM -0800, Nate Jenkins wrote:
> > >
> > > Does "frobbing" help?  Maybe investigate "frob"  I am not sure if the
> lack
> > > of this could do what you describe or not.  Or if it is chip specific...
> > >
> > > Nate
> > >
> > >
> > >
> >
> > I do not believe that the lack of "frob" would do this because
> > the main problem is that when you send only one byte and measure
> > the pins voltage they are not what you expect.
> >
> > In what way do you suggest the lack of frob causes the problem?
> >
> > -- 
> > Thiago A. M. Delatorre
> >
> > _______________________________________________
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> > Linux-parport at lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-parport
> >
> 
> 
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-- 
Thiago A. M. Delatorre