Re: Apple ][ to VGA monitor adapter board - looking for best color decoding method

[Warren Ernst <wernst@gmail.com>]

On Apr 10, 2:58 pm, sicklittlemonkey <Nick.Westg...@gmail.com> wrote:
> On Apr 11, 6:09 am, ferd...@gmx.de wrote:
>
>
>
> > On 10 Apr., 15:22, sicklittlemonkey <Nick.Westg...@gmail.com> wrote:
>
> > > On Apr 10, 10:03 pm, ferd...@gmx.de wrote:
>
> > > > On 10 Apr., 13:39, sicklittlemonkey <Nick.Westg...@gmail.com> wrote:> On Apr 10, 2:02 pm, "Michael J. Mahon" <mjma...@aol.com> wrote:
>
> > > > > > It takes a peek into the future to know that the next pixel will
> > > > > > extend the current color
>
> > > > > Not if output lags input by 1 bit.
>
> > > > > Emulators have done this in a reasonable manner for years with various
> > > > > algorithms, so I don't see why the hardware solution we've all been
> > > > > waiting for should be so much more limited.
>
> > > > > Anyway, no-one else is complaing, so I guess I've had my say. ;-)
>
> > > > Well, one needs to peek further into the future. The next pixel says
> > > > whether the dot is green or white. But the dot after the "violet" dot
> > > > determines whether this is a green dot or a green line. So one need to
> > > > look 2 bits into the future. And in DHIRES this becomes 4 bits.
> > > > This makes the amount of data explode - there are way to many
> > > > combinations.
> > > > I might be able to handle that on a second board but it is not going
> > > > to fit on the present card. It barely fits how it is designed yet.
>
> > > > Ferdinand
>
> > > True, DHires is more complicated, even without the mixed or extended
> > > DHires modes on the AppleColor RGB card.
>
> > > I'd like to see a method 1 shot of Airheart if you have time.
> > > Again, kudos for what you've accomplished.
> > > People have been pining for such a card.
>
> > > Cheers,
> > > Nick.
>
> > Well I needed to disassemble the old color circuits to set up a new TV
> > emulation test. So there is not going to be a screenshot of Airheart.
> > But: The circuit I got now is fairly simple. so it _MIGHT_ fit on the
> > PCB. There is still a some trouble with color rendition and with
> > ringing. And the circuit - as it is now - doesn't have either TEXT
> > mode support or "method 1" for LORES. Here are some screenshots of the
> > early design:
> > Airheart:http://img262.imageshack.us/img262/6116/airheartvgatvemuzi6.jpg
> > LORES color test:http://img522.imageshack.us/img522/1493/lorestvemucr1.jpg
> > Pacman(HIRES):http://img134.imageshack.us/img134/5889/pacman1tvemuri6.jpg
> > (the ghosts are blurred because I had to use .2 secs exposure)
>
> > Ferdinand
>
> It looks good!
>
> (Kinda surprised more people aren't commenting on this ...)
>
> Cheers,
> Nick.

Progress looks amazing. I'd probably be interested in one of these if
only I knew exactly what it is you've got here. Are you designing
something that plugs into the RGB port of a GS? Of a special RGB card
for a //e? Of the RCA video out jack of either computer?

-Warr