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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: skurk on June 14, 2007, 06:33:49 PM

Title: Commodore 128 - VGA possible?
Post by: skurk on June 14, 2007, 06:33:49 PM

Running a bit off-topic here, but I'm giving it a shot anyway.

A colleague came up to me and asked if I wanted "something that's twice as good as a C64" - for free.  Obviously, I accepted the offer without hesitation.  Turned out it was a C128 in original box with cassette player, PSU, games, joysticks - the lot.  Yay!

Now, I don't know much about C128's, but I noticed the RGBI connector on the back.

Is this similar to the RGBI on the Amiga?
If so, are there any scandoublers avaiable for the C128?

Title: Re: Commodore 128 - VGA possible?
Post by: buzz on June 14, 2007, 06:50:41 PM

Its 15khz RGB. But I dont know if its TTL or not. I think not though. Should work with any RGB scan doubler too.

Note that the RGB output is only for the 80 column c128 mode. Not the C64 graphics modes as they are not RGB but Chroma/Luma

I use a 1084 on my c128.

Title: Re: Commodore 128 - VGA possible?
Post by: swift240 on June 14, 2007, 06:59:08 PM

I use a C128 on my Philips CM8833-II monitor for the 80 Column mode.
It is a 15Khz output so a VGA monitor will not work.
Here are the pinouts for the RGBI output.

1:- GND
2:- GND
3:- RED
4:- GREEN
5:- BLUE
6:- Intensity
7:- Monochrome
8:- Horizontal Sync
9:- Vertical Sync

It is TTL logic

Take a look here:-

http://www.hardwarebook.info/C128_RGBI

Title: Re: Commodore 128 - VGA possible?
Post by: swift240 on June 14, 2007, 07:03:22 PM

Ohhhh yes bye the way.

There is a device for the ZX Spectrum and Playstation in fact any things that gives out a 15Khz signal that will turn it into a 31Khz

NOT a scandoubler as you understand it for an Amiga.

Is was put on a Italian website that does this sort of thing for the Spectrum and Playstation.
They do work and don`t cost as much as an Amiga scandoubler does.
Don`t ask me for the website, I don`t remember but do a search on google.

Title: Re: Commodore 128 - VGA possible?
Post by: AmiDog on June 14, 2007, 07:11:56 PM

Have a look at this (http://landover.no-ip.com/128/viewtopic.php?id=453). The RGBI port is a digital one, which will only work with a CGA monitor, or one of the 1084 and compatibles.

However, as the RGBI output is driven by the VDC-chip, which can be set to output just about anything, some monitors may have trouble displaying certain screenmodes. If your C128 has 64KB VDC memory, you can go up to some 720x700 pixels (overscaned 640x400 interlaced)...

Title: Re: Commodore 128 - VGA possible?
Post by: skurk on June 14, 2007, 10:39:25 PM

Ok, I wasn't aware that the RGBI was for 80-column only.

Thanks for all the replies.  Guess I'm going to have to hook it up to an LCD TV after all then :-)