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

[Nicolas Pomarède <npomarede@xxxxxxxxxxxx>]

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