ccc121e@monu6.cc.monash.edu.au (Dave Schwarz) (07/02/90)
Hi everybody, after reading about numerous people who want
to have either 24bit plane color or 256 colors at 800*600
I started thinking of different solutions. This is what I came up with
The basic solution is simple when you think of it, simply said
is to sync 1 or more agnus/denise chipset combinations.
With 1 agnus/denis chipset this would lead to either 24 bit planes
at 320*400 in ham or 8 bit planes at 640*400. Of course using overscan
would up this to 720*540 which is very close to 800*600. As well you
these colors would be chosen from 24^2 colors (16 million colors)
How would this work ?
Like this I think
(Please disregard the fact that there are 2 video slots
and the zorro slot doesnt line up with the video slot
at least on the a2000 and the fact that this schematic is not
drawn to any sort of scale and the fact that I ran out of screen;-)
red out (0:7)<------+
blue out (0:7)<----+ |
green out (0:7)<--+ | |
+-+ | | |
| | Video slot | | |
| | +------+
| | 4 bits Red (0:3)--------------------------------------------| 3 |
| | 4 bits Blue (0:3)-------------------------------------------| 8bit |
| | 4 bits Green (0:3)------------------------------------------| d/a |<-----+
| | sync signels in-----------------------+ +--sync out---| conv |<---+ |
+-+ | | | |<-+ | |
| | +------+ | | |
+-+ | | | | |
| | \/ | | | |
| | +-------------+ +-----+ | | |
| | Zorro bus slot | | | | 4 bits | |
| | | Agnus II |<-data->| D | red (4:7)
| | +---+ | | | | e | 4 bits-+ |
| |<-Address lines->| |<----------->| | | | n | blue (4:7)
| | | | auto config +-------------+ | | i | 4 bits---+
| | +---+ stuff ^ ^--+address--->| s | green (4:7)
| | | | | | | II |
| |<-data lines-------+------------------+ | | | |
| | | | +-----+
| | | |
| | +--------------+
| | | |
+-+ | 1meg chipII |
| ram |
| |
+--------------+
If you wanted to you could put 2 of these circuits on a mother board and modify
the circuit such that each agnus/denise chipset put out only one color
ie agnus/denis on mother board 12 bits of blue
agnus/denisII 12 bits of red
agnus/denisII 12 bits of green
This Would allow you to have 640*400*12 bit planes or 4096 colors on the screen
at once from 2^36 colors. Overscan would give you 720*540*12.
The other advantage of doing this ?
Well the hard ware is known to work on an Amiga :-)
The software to drive the hardware has been written for a single chip
it just needs to be modified for 2 or three chip sets (bigger :-) )
You now get 2 or three blitters to munch data and the cpu wont bog down
as much as a 800*600*8 bitplane when scrolling (just a guess I may be wrong)
It uses commodore approved hardware ;-)
It seems to me to be a neat solution.
What do all you guys out there think ?
Dave.
Who has an Amiga1000 and would simply love an A3000
.ps (if anybody loves this idea then I will take an A3000 as payment :-)
--
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|Dave Schwarz @ CIT (Chisholm Institute of Technology)| Dont you just love a |
|900 Dandynong Rd,East Caulfield,Vic,Australia _______| place that takes away |
|ccc121e@monu6.cc.monash.edu.au <------_|your name and give you a number |