Newsgroups: comp.sys.transputer
From: msandford@delphi.com
Subject: Re: IMS B419 / G300 parameters
Organization: Delphi (info@delphi.com email, 800-695-4005 voice)
Date: Fri, 17 Jun 94 00:07:32 -0500
Message-ID: <R60zQgM.msandford@delphi.com>

Rolf Skeie <rfs@ffi.no> writes:
 
>I'm having some trouble with programming the G300-chip for standard
>PAL/SECAM video format. Is this possible at all?
>Is there anyone out there that can help me with some sample
>parameters for different video-resolutions? (1024x768 SVGA
>would be nice, to)
>I have the F003 2D-library, but only a 1280x1024 Hitachi monitor
>is given as an example. Not enough...
 
It should be possible to get it to work at PAL/SECAM type rates but the
on chip PLL can't go that low so you will need to use an external oscillator
that has a clock 4 times the desired pixel clock rate.  I know that that
would be about 50 Mhz for NTSC (12.5 x 4) which would be similar on
PAL/SECAM one solution that we came up  with was to generate a standard
video signal  like VGA for which there are VGA -> NTSC converts.  I would
guess that similar devices exist in europe.  I have example occam code to
program the G300 for VGA at work e-mail if interested.  If you could send
specs for PAL/SECAM I could possibly help suggest appropriate G300 parameters
to make it work.  The information in the data book has a couple of mistakes
which of course make following the example a bit more tricky again.  One
word of cation is that the on chip PLL (which you have to use) only support
dot clock frequencies that are multiples of 5MHz (5, 10, 15 etc...) and
[D
signal characteristics (i.e. sync widths) that are even multiples of
4 times the pixel clock (i.e. horizontal sync must be 4, 8 ,12, 16 pixel
clocks wide).  This limiation will mean that you will not be able to
exactly match signal characteristics of your monitor, may be close enough
and may be not, which also depends on how much slop your monitor allows.
In general monitors allows a fair amount of deviation from specs and
try to match inputs rather than specs but other devices such as VCR's are
more picky.  E-mail if you would like help.
 
--------------------------------------------------------------
Mark Sandford
msandford@delphi.com     or   sandford@cris.com
Bad spellers of the world untie !!!!!!!
 
 
P.S. I have source code in occam for most general graphics operations
which allows customization which the standard libaries lock you
out of.

