Re: VIC-II and luma levels

From: Richard Atkinson <rga24_at_cantab.net>
Date: 12 Jan 2012 20:02:55 +0000
Message-ID: <Prayer.1.3.4.1201122002550.26211@hermes-2.csi.cam.ac.uk>
On Jan 12 2012, Gerrit Heitsch wrote:

>I know there is a major difference in the PAL version of the VIC-II 
>between the 6569R1 and all later versions. The R1 is only able to do 5 
>luma levels (1-4-6-4-1 number of colors per level) for the 16 colors 
>while the later versions are able to do 9 luma levels 
>(1-2-2-2-2-2-2-2-1). Some demos look quite odd on the R1.
>
>I know there were timing changes between revisions in the NTSC versions 
>of the VIC-II (6567), but were there also changes with the luma levels? 
>And how many levels does a 6567 have?
>
>It's easy enough to check with a little BASIC program and some time to 
>sort the colors into the right sequence. Then turn down the color.

I have a 6567R56A here. It has five luminance levels and 64 cycle / 262 
line timing. The 6567R8 has nine luminance levels and 65 cycle / 263 line 
timing.

Although the timing stayed the same between 6569R1 and 6569R3, the number 
of luminance levels changed and the timing of video accesses changed also. 
Christian Bauer's document has the details. You can open the side borders 
and put sprites in the borders, and you'll get different results for 
sprites 1 - 8 between 6569R1 and 6569R3.

I've never seen one, but there is also a 6567R5 which is apparently very 
similar to the 6567R56A.


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Received on 2012-01-12 21:00:04

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