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

From: Anders Carlsson <anders.carlsson_at_sfks.se>
Date: Thu, 2 Sep 2021 15:13:24 +0200
Message-ID: <4b1ab324-4f3a-bce3-1684-1cee49e382a3_at_sfks.se>
Torsten Kracke wrote:
> 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.

Interesting, I never considered going beyond 31. But it is correct that 
33 is the maximum value I can obtain as well without jumbled characters 
(PAL machine).

Values beyond 35 won't change the screen so I would assume that is the 
absolute max. Since we're filling the screen with blank spaces, perhaps 
jumbled characters is not an issue, and ensuring every cycle is covered 
by the text area is more important.

1024 / 35 gives us maximum 29 double height rows = 58 normal rows. I 
haven't checked how many cycles there is on the screen, if the VIC-I 
chip even can output that many rows.

POKE 36864,0:POKE 36865,0:POKE 36866,35:POKE 36867,58+1 would probably 
give us the biggest possible screen.

It remains to figure out if the border still gets drawn somewhere before 
the screen appears at 0,0 or for some crazy reason gets drawn after this 
super oversized area.

By the way, these two POKEs give a very interesting result with all text 
jagged up:

POKE 36864,0:POKE 36866,34

35 columns makes some characters jumbled but mostly readable.

Best regards

Anders Carlsson
Received on 2021-09-02 16:00:03

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