RE: [stella] problems with monitor syncing

Subject: RE: [stella] problems with monitor syncing
From: "Fred Quimby" <c9r@xxxxxxxxxxx>
Date: Mon, 2 May 2005 23:23:30 -0400
I believe that there are online databases somewhere that have the specs on 
most monitors. maybe?  However, the only VGA monitors that 
will sync this low are very, very old.  Some of the first NEC Multisyncs 
could, for example, which were made in the late 80's or early 90's or 
thereabout.  I know because I used to have one.

One alternative is a projector if you have access to one.  Most are designed 
to display NTSC via composite video, so there's a good chance that they 
would sync to 15 kHz if this was connected to the VGA input.

Another alternative is a television that accepts VGA input.  These aren't 
particularly common but they do exist, usually in 27-36" sizes, but there's 
also a good chance that it will sync to 15.7 kHz just fine through the VGA 

Either way, though, I think it would be cool if this would support native 
VGA too instead of just composite video/S video or whatnot.  You might be 
able to do it all within the FPGA, as you just need a shift register or two 
to hold the pixel data from the TIA, and then you could basically copy much 
of the TIA display/chroma/sync logic, except make this part display the data 
at twice the clock rate two times each for each scanline.

>Hash: SHA1
>On Mon, 2 May 2005, Fred Quimby wrote:
> > 99% of VGA monitors cannot sync to a horizontal frequency lower than 
> > twice that of a television (i.e. most VGA's can't do less than about 30
> > kHz.)  Some really old VGA monitors will, but I wouldn't expect that 
> > are going to own these monitors.,
> >
> > A workable solution would be to store the data from each scanline in a
> > buffer.  Once full, output the buffer at twice the speed, and do it 
> > In fact this is exactly what many simple TV to VGA converters do.
>Any way to find out before buying a monitor, how low in frequency it can 
>We need to get down to what here, 15.72 KHz?
>- --
>Version: GnuPG v1.2.1 (GNU/Linux)
>Archives (includes files) at
>Unsub & more at

Archives (includes files) at
Unsub & more at

Current Thread