RE: [avrdude-dev] Parallel port doesn't keep programmed states

[Marc Wetzel]

Hi alltogether,

Correct me if I'm wrong, but I think that giveio is no "real" driver at
all.

It just sets the appropriate rights to the user/program to write to the
(normally locked) ports at all.

It is not buggy. There is nothing to be buggy in it :) Have you ever
looked over the code?


What I saw all the times, is that users have print-queues running, with
open documents in it and that
interferes with any port writing at all...


Greetings
/Marc

> -----Original Message-----
> From: address@hidden 
> [mailto:address@hidden On Behalf 
> Of E. Weddington
> Sent: Monday, November 24, 2003 3:03 PM
> To: idefixx; address@hidden; Jan-Hinnerk Reichert
> Subject: Re: [avrdude-dev] Parallel port doesn't keep 
> programmed states
> 
> 
> On 24 Nov 2003 at 13:26, Jan-Hinnerk Reichert wrote:
> 
> > On Monday 24 November 2003 00:58, idefixx wrote:
> > > > You need to disable Windows XP Plug'n'Play for the 
> parallel port.
> > > >
> > > > I solved the problem with the following file: 
> > > > http://www.student.dtu.dk/~s991363/avr/avrdude/winxp1.reg
> > >
> > > But is it really necessary to change the windows registry? What 
> > > changes are going on during the read out of the AVR 
> flash, as after 
> > > doing a read out the problem disappears, too.
> > 
> > I don't know the windows ppi-code. However, there should be no
> > difference in the called functions, since we only transfer 
> > SPI-commands.
> > 
> > I guess there is either some magic sequence occuring on the 
> port while
> > reading or (more likely) it has something to do with the 
> frequency of 
> > access. For _unpaged_ memory writing does big pauses when 
> writing. So 
> > perhaps windows thinks there is a valid device and stops 
> looking, if 
> > there only is enough "action" on the port.
> > 
> > Have you tried the latest CVS source? Recent changes in the polling
> > code make writes look more like reads in this regard. There 
> is a good 
> > chance that this makes your problem go away ;-)
> > 
> > /Jan-Hinnerk
> > 
> 
> 
> I'm not necessarily an expert on Windows and drivers for 
> Windows, but from what I 
> remember, I believe it has to do with the parallel port 
> driver we have to use, giveio, 
> and Windows XP. I think that the giveio driver is very simple 
> and doesn't "play well 
> with other" drivers, especially the parallel port driver on 
> WinXP and conflicts arise 
> causing other signaling on the parallel port pins, i.e. not 
> from avrdude. Disabling 
> "Plug'n'Play" seems to stop this problem on WinXP. The file 
> that was suggested, 
> takes care of disabling Plug'n'Play via the registry, and 
> makes a nice, automatic way 
> (i.e. from the command line) to do this.
> 
> What is really needed is an open source, Windows parallel 
> port device driver, that 
> works well with Windows NT, 2K, XP just for avrdude (and for 
> uisp, too) that allows 
> direct writing and reading of the parallel port pins. The 
> giveio driver is just too simple 
> (IMHO) and not robust enough. However, this will take a 
> volunteer who has device 
> driver experience and the tools to build it, neither of which I have.
> 
> If I'm incorrect about anything, feel free to correct me. 
> Also, if Alex Shepherd (NZ) is 
> listening in, perhaps he'll have something to say about this.
> 
> Eric
> 
> 
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