Re: 256 Color on Apple II+?

[The Wizard of Oz <wizard@emeraldcity.gov>]

On Thu, 03 Jun 2004 02:11:23 +0000, Bryan Parkoff wrote:

>     Is it possible to support 256 colors on Apple II+ by using video
> controller card?  You would have to build IC board to make controller card
> from scratch.  256 colors will be stored on location from $1000 through
> $E200 (like HGR from $2000 through $3FFF).

	Why not have the video memory stored on board. It could be accessed
through a series of commands sent to the card. The advantage to having the
memory on the card instead of using the memory on the motherboard is it
could be faster. The card does not have to rely on the same clock as the
rest of the computer other than when communicating with the computer.

>     Will it allow the assembler programming code to tell the softswitch like
> $C080-$C08F to read aux memory rather than main memory through video
> controller card's memory chip before aux memory will display in the screen.
> It looks identical to Nintendo 8-Bit that main memory and aux memory are the
> optional to use switches back and forth.

	Very slow. The ][+ is running at 1MHz where as some PC monitors support
changes much faster. Then there is the matter of what resolutions are
supported. Even if the resolution is kept the same the amount of memory
needed will be eight times what is currently being used. Putting all the
graphics memory and processing on the card wouldn't necessarily speed up
the plotting of individual pixels, but it would speed up things like fills
and drawing polygons. Anything which involves moving memory would also be
sped up. What is more, since memory is relatively cheap, the card could
contain multiple buffers depending on the resolution.

	The assembler programmer would assign a buffer containing the command
(perhaps a number) and a series of parameters. They would then pass the
buffer address to a routine handler which would then pass the relevant
information to the card. (Sound familiar folks) ;-)

>     Do you think that video composition can handle 256 colors at higher
> frequency?  Please let me know what you think this idea.

	This is a possibility. There were a couple of cards for the //e and GS
which did pretty much this. The more routines which can be shifted to the
card the better. Remember you are dealing with no more than 64K of RAM on
the machine.

	Saying something is possible doesn't mean it is practical. Sure someone
can do it just to show it can be done. A one or two off production run is
possible. These would be little more than expensive prototypes. I gather
the price reductions start at 100 cards as a minimum. Can you find 100
(150 would be better) ][+ users willing to spend $250 on a video card?

				Later
				Mike