Re: Ultimax questions

From: Gerrit Heitsch <gerrit_at_laosinh.s.bawue.de>
Date: Tue, 22 Oct 2013 20:17:41 +0200
Message-ID: <5266C145.10507@laosinh.s.bawue.de>
On 10/22/2013 07:43 PM, Bil Herd wrote:
>
>> Have you seen some of the things people do with the VDC?
>
> Yes there is some amazing stuff out there.  I think the more problems a chip
> has the more beautiful things you can trick it into doing (reliability being
> a different issue)

Well, yes, even TED can be tricked into doing interesting things. Thanks 
to whoever made the horizontal and vertical scan position registers 
writable.

And people have been able to make the VDC generate something a VGA 
monitor can display. Granted, the picture is rather blocky and reminds 
you of the VIC-20, but still.

http://www.forum64.de/wbb3/board314-au-erhalb-des-c64/board13-sonstige-commodore/board95-c128/54247-vdc-vga-mania/

(German text)



>> I thought all VDCs in the C128 are able to work with 64K, you just have to
>> replace the 41416 DRAMs with 41464?
>
>    I actually donít know for sure, just having heard people refer to the 64k
> it sounded like there was more functionality (I was gone from CBM by then).
> There were also differences in the C128D that they released vs. the one we
> had ready for release in the beginning, and I donít know what all of those
> differences are except what people mention (video noise, etc)

The later revision of the VDC can generate an IRQ, something the first 
version couldn't which, from what I remember, caused all kinds of 
consternation ('you can check any time you like...). Also, the later 
C128D shipped with 64K video RAM.

  Gerrit



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Received on 2013-10-22 19:00:11

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