C128 to VGA

Gmav

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Jul 13, 2003, 4:48:13 AM7/13/03

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Is it possible to make a cable to go from the C128 RGB port to a VGA
monitor?

Peter van Merkerk

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Jul 13, 2003, 11:34:36 AM7/13/03

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> Is it possible to make a cable to go from the C128 RGB port to a VGA
> monitor?

You could make the cable, but it would work. One problem is that the RGBi
output of the C128 is digital and VGA is analog. This problem could be
solved with a few resistors. The big problem is the scanrate of the C128
RGBi output (15.75 kHz); most VGA monitors won't go lower than 30 kHz. So
you need a scanrate converter for this
(http://www.btinternet.com/~commodorescene/vga.html).

--
Peter van Merkerk
peter.van.merkerk(at)dse.nl

Daniel Karlsson

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Jul 13, 2003, 11:51:05 AM7/13/03

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Gmav wrote:
> Is it possible to make a cable to go from the C128 RGB port to a VGA
> monitor?

No. The C128 RGBI isn't compatible with VGA. The C128 RGBI is digital RGB
and VGA is analog RGB. But you can use a CGA or a EGA monitor with the C128
RGBI.

For pinouts: http://www.hardwarebook.net/

Regards
/djk

Peter van Merkerk

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Jul 13, 2003, 2:38:32 PM7/13/03

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> You could make the cable, but it would work.

Correction: it would NOT work.

Gmav

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Jul 14, 2003, 4:25:26 AM7/14/03

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Ok thanks for the info. Would it be possible to make a cable to a composite
or svga input to a tv, maybe just using the luminance for an 80 column bw
display?

"Peter van Merkerk" <mer...@deadspam.com> wrote in message
news:beru7c$8d5u5$1...@ID-133164.news.uni-berlin.de...

Peter van Merkerk

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Jul 14, 2003, 7:33:08 AM7/14/03

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> Ok thanks for the info. Would it be possible to make a cable to a
composite
> or svga input to a tv, maybe just using the luminance for an 80 column
bw
> display?

You can connect the 80 column output to a TV without tricky electronics
since the scanrate of the C128 is the same as used by TV's. If you are
satisfied with just black-and-white it is very simple; pin 7 on the RGBi
port of the C128 outputs a composite BW signal (of the 80 column screen)
which can be connected directly to a TV with a video input (e.g. SCART
connector). For more details see
http://www.hardwarebook.net/connector/av/c128rgbi.html. If you want
color and your TV has a SCART connector that accepts RGB signals, you
could try something like this:
http://www.softwolves.pp.se/cbm/maskinvara/scart.en.html.

Good luck!

Jeff Ledger

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Jul 14, 2003, 5:23:30 PM7/14/03

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> No. The C128 RGBI isn't compatible with VGA. The C128 RGBI is digital RGB
> and VGA is analog RGB. But you can use a CGA or a EGA monitor with the C128
> RGBI.

Somehow I suspect this is a stupid question, but
Is the CGA/EGA monitor directly compatible without custom cable?
And does it work in 64 mode?

Thanks
Jeff

Peter van Merkerk

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Jul 14, 2003, 5:49:54 PM7/14/03

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> > No. The C128 RGBI isn't compatible with VGA. The C128 RGBI is digital
RGB
> > and VGA is analog RGB. But you can use a CGA or a EGA monitor with the
C128
> > RGBI.
>
> Somehow I suspect this is a stupid question, but
> Is the CGA/EGA monitor directly compatible without custom cable?

A CGA monitor can be connected directly to a the C128. Things can be bit
less straightforward with an EGA monitor, unless the monitor is dual mode
(it can also be configured to accept CGA type signals).

> And does it work in 64 mode?

No, you cannot directly connect the 40 column composite video output to a
CGA or EGA monitor.

Sam Gillett

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Jul 14, 2003, 7:14:32 PM7/14/03

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Jeff Ledger wrote ...

Speaking of an old CGA monitor that I have used, the cable on the monitor
works great in 80 column mode. It will not work in 40 column mode, which
puts the C128's 64 mode out of the question.

Best regards,

Sam Gillett aka Mars Probe @ Starship Intrepid 1-972-221-4088
Last 8-bit BBS in the Dallas area. Commodore lives!

Dave R.

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Jul 15, 2003, 9:12:29 AM7/15/03

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jle...@cyberstreet.com (Jeff Ledger) wrote in
news:706f6242.03071...@posting.google.com:

>> No. The C128 RGBI isn't compatible with VGA. The C128 RGBI is digital
>> RGB and VGA is analog RGB. But you can use a CGA or a EGA monitor
>> with the C128 RGBI.

This would probably be a good time to plug the VGA adapter being built by
Commodore Scene magazine.

http://www.btinternet.com/~commodorescene/vga.html

It supports both 40 & 80 column mode, and is being designed especially to
look good when used with a Commodore computer.

Daniel Karlsson

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Jul 15, 2003, 11:26:44 AM7/15/03

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Just one problem: It doesn't exist. I'm going to buy one as soon as they
come out though (or pre-order one as soon as that's possible).

/djk

Dave R.

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Jul 15, 2003, 12:36:45 PM7/15/03

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"Daniel Karlsson" <daniel.j...@telia.com> wrote in news:U2VQa.20453
$dP1....@newsc.telia.net:

> Just one problem: It doesn't exist. I'm going to buy one as soon as they
> come out though (or pre-order one as soon as that's possible).

Same here. Allan Bairstow's updates on the project's progress have become
teases. Especially the last one with the picture of the prototype board.

:)

Jeff Ledger

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Jul 15, 2003, 8:35:50 PM7/15/03

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> Same here. Allan Bairstow's updates on the project's progress have become
> teases. Especially the last one with the picture of the prototype board.

No kidding... That last one is about to become wallpaper. :)

Jeff

A E

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Jul 15, 2003, 11:36:34 PM7/15/03

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Peter van Merkerk wrote:

>
> No, you cannot directly connect the 40 column composite video output to a
> CGA or EGA monitor.

If it's a monochrome CGA monitor, it plugs right in. I used to annoy the @#@#$
out of people at school in the early 90s. The hardware labs still had XTish
machines hooked up to mono CGA monitors, to which I promptly plugged my hand
painted zebra-striped VIC 20 to. Since I could write BASIC code to poke math
derived values to memory, I was way ahead of the poor sods on the XTs with
calculators using debug to enter bytes into memory...