Re: [hatari-devel] video freq set to 60 Hz instead of 50 Hz for Falcon VGA

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Le 06/03/2024 à 19:05, Anders Eriksson a écrit :

On Wednesday, 6 March 2024 at 14:48, Nicolas Pomarède <npomarede@xxxxxxxxxxxx> wrote:

Le 06/03/2024 à 14:29, Nicolas Pomarède a écrit :

Hi

I didn't try screenpain yet ; when generating asm source for vga 32 Mhz,
can you compare it to vga 25 Mhz to see what is changing ?

I had the feeling that register-wise only bit 2 in ff82c0 was involved
in RGB/VGA, by setting clock to 25 or 32 MHz.

I don't see which setting allows vga with a "non vga" clock.


nevermind, I tried it myself :

--- VGA32.S 2024-03-06 14:38:26.928919655 +0100
+++ VGA25.S 2024-03-06 14:41:35.710411188 +0100
@@ -8,14 +8,14 @@
* Monitor: RGB/TV
* 640*400, 16 Farben, 50.0 Hz (interl.), 15625 Hz

- MOVE.L #$1FE0199,$FFFF8282.W
- MOVE.L #$50004D,$FFFF8286.W
- MOVE.L #$FE01B3,$FFFF828A.W
+ MOVE.L #$1900141,$FFFF8282.W
+ MOVE.L #$3E004D,$FFFF8286.W
+ MOVE.L #$16C0156,$FFFF828A.W
MOVE.L #$2700265,$FFFF82A2.W
MOVE.L #$2F007E,$FFFF82A6.W
MOVE.L #$20E026B,$FFFF82AA.W
MOVE.W #$200,$FFFF820A.W
- MOVE.W #$182,$FFFF82C0.W
+ MOVE.W #$186,$FFFF82C0.W
CLR.W $FFFF8266.W
MOVE.W #$0,$FFFF8266.W
MOVE.W #$6,$FFFF82C2.W

So, clock bit is changed in ff82c0 (which is what Hatari is using at the
moment), but it also changes the 6 registers at ff8282 - ff828c that
define the duration for horizontal lines.

This is sthg that is not supported at the moment, this will require much
more code (and a better understanding of all these regs for myself :) )

Nicolas


Yes I figured as much, that's why I asked Zerkman to chip in previously :).
He did the Videl Inside software that allows to configure non-standard video modes.

I also downloaded videl inside 2.04, this will certainly be a precious source to better understand the Videl and some 'mixed' mode such as this VGA 32 MHz

for reference, PRG and sources can be found here  :

https://demozoo.org/productions/317112/

Nicolas




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