Re: VC-20 all 16 colours full-screen?

From: Torsten Kracke <tokra_at_tokra.de>
Date: Thu, 2 Sep 2021 10:19:51 +0200
Message-ID: <2c03f031-e45a-2805-c55d-afadd4095a10_at_tokra.de>
silverdr wrote:
>
> > When I run it on `xvic` I still get one "column" worth of border 
> colour on both left and right.
>
> I just tested on a real PAL VIC-20. With POKE 36864,0 and POKE 
> 36866,31 (+128 depending on the location of the screen matrix) you 
> eliminate the border so you can adapt Michiel's program with these 
> changes. Combined with POKE 36865,0 and POKE 36867,39 (or even 41 if 
> you really must ensure that the entire screen is covered), it should 
> be possible to cover the ENTIRE screen area. Since you're not putting 
> any text or graphics on the screen, we can ignore the fact that quite 
> a bit of the screen will fall outside of visible area on pretty much 
> every monitor you can find.
>
> Sure perhaps you can capture the video signal with some device that 
> still picks up border, but since we set VIC-I to begin the screen at 
> the absolute lowest X and Y coordinates and expanded the screen the 
> maximum number of columns and rows (with 8x16 mode), if it still 
> displays border colour at any place, there is nothing we can do about 
> it from software.
>
On my real PAL VIC-20 I can get to 33 columns with $9000 set to 0 or 1 
before the characters become jumbled up some character-lines down. So 
contrary to VICE where you can not go over 32, the real VIC supports 
more, but some internal counters are probably going bonkers then. 
Anyway, with standard display-devices you simply cannot tell visually 
whether the VIC does switch to the border-color at one point. 
Theoretically with 71 cycles the maximum width would be 35.5 chars, so 
if you set $9002 to 36 and $9000 to 0 you have done all you can from 
software.

tokra
Received on 2021-09-02 11:00:02

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