Fwd: Re: VGA output and cpufreq.

[Oleg Gusev]

The list is overzealous about the *.exe attachments...

----------  Forwarded Message  ----------

Subject: Re: VGA output and cpufreq.
Date: Sun, 27 Jun 2004 22:18:58 +0200
From: Oleg Gusev <oleg@usm.uni-muenchen.de>
To: Matan Ziv-Av <matan@svgalib.org>
Cc: jornada820@lists.linux.it

On Sunday 27 June 2004 08:41 pm, you wrote:
> In practice even after those calculations, a lot of trial and error is
> needed.

Thanks. I have learned a lot of interesting things.

> bit 1 of PBDWR. When it is zero, only the sync signals go to the
> monitor.

I was monitoring the PBDRR with the program hpcgpb.exe
(attached). It is hpcboot.exe that stops before booting and
is reading the register in an endless loop. If the value changes,
it will be put on the LCD or serial port, depending on your
settings.

> I saw your table. The only question I have is what should be instead of
> all the question marks?

Who knows. I have not seen any changes of these values. The
wince ROM was developed for the machine with a different
hardware setup, so we can only guess. Or disassemble the
wince drivers, which is painful, because i don¨t know the
ROM filesystem layout (how dlls and programs are mapped into
the memory).
If you have a CDs that came with jornada, then you should
have a hpvoutst.exe program replacement. If somebody
on the list can send me this program, we can learn more.
Unfortunately, i have lost my CDs, and it is impossible to
download them from HP.

> I think it will be very useful to have a windows program that upon
> running, dumps all 1101 and 1100 registers to a file (or even better,
> the serial port). So if anyone has an environment for compiling windows
> programs, and knows how to read the registers, and has the little
> patience needed to write such program, please do.

Well, i dump the registers i cared about to the screen/file and
the list can be extended. It is not rocket science, and i can post
the source code.

> Do you not use the same as windows does. LCD displays are usully not
> multiscanning, so the best is to use the same clock that windows uses.
> The formula given in the SA1100 manual is PCD=(CCLK/(2*pixclock))+2.

Yes. The problem is that if we use wince value, then the LCD flickers.
George Almasi put a much lower value and i have simply doubled
his value. This setting is 10% higher than in wince, and everybody
is happy. Since i do not completely understand the theory behind it,
it will be great if somebody knowledgeable like you can explain the
rationale.

 Oleg.

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