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Anyone have info on a Dicomed "Color Controller" (NEC 7220 graphics)?

E

erd

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Apr 29, 2003
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Location
Central OH
Greetings, all,

I've recently had cause to go through all the Apple II stuff I have and this bubbled up to the surface. I got it from University Surplus quite some years ago, and even a recent Google search reveals my initial queries but no answers.

Recent explorations reveal that it's a box with an NEC 7220 graphics processor and 128K of local RAM on one board, adjustment and timing on another board, and a cable back to an Apple bus card that passes up D0-D7, A0-A3 (latched on Phi 1), R/W (latched on Phi 1), /DEVSEL, Q3 clock, and RESET. Presumably, it presents the two uPD 7220 registers back to 6502 memory space and you just stuff commands at it and watch the results on the attached monitor. I can find no software or docs, or even press releases or advertisements.
Given the flexible nature of the uPD 7220 and the 128K of RAM, there are many possibilities. The Sony A/V connector suggests that this was expected to be used at 15KHz and probably at some variation of 640x200 or 320x400 (interlaced) and up to 8-bits of color, but that's just a guess (those particular configurations use most of the 128K of RAM).

Anyone ever see one of these? Anyone have any applications for one of these?

-ethan

1666115663460.png1666115674217.png1666115681389.png1666115689573.png
 
That's very interesting, I have not seen anything like that before. I did a bit of searching, not much comes up. I see some references to them with some sort of slide making products.

I have been playing with a 7220 based apple card called the Grafex and have some very basic drawing software working for that. You could possibly use that sw as a base and modify it. I think you would need to do a bit of reverse engineering of the box though to work out main pixel clock, and how the color is implemented with the board. Do you have any pictures of the board with the 7220 on it, i'd be interested to see them.

/Rob
 
Yes. Not much online about this product. I asked on FB and someone else said they had two of them, but no software or docs.

I've worked out the pinout of the Apple card/40-pin cable

Code: 
2-40 even GND
 1 A2      ['373 pin 6]
 3 D0      [Apple bus 49]
 5 D1      [Apple bus 48]
 7 D2      [Apple bus 47]
 9 D3      [Apple bus 46]
11 D4      [Apple bus 45]
13 D5      [Apple bus 44]
15 D6      [Apple bus 43]
17 D7      [Apple bus 42]
19 A0      ['373 pin 2]
21 RESET   [Apple bus 31]
23 A1      ['373 pin 5]
25 R/W     ['373 pin 12]
27 A3      ['373 pin 9]
29 /DEVSEL [Apple bus 41]
31 Q3      [Apple bus 37]
33 X       N.C.
35 X       N.C.
37 X       N.C.
39 X       N.C.

I can get a picture of the lower board.
 
I tidied up my test program that I used on the AppleII for the grafex card. You can grab it from here: https://www.dropbox.com/s/kg2mc6donafj28f/grafex_test.zip?dl=0

This needs the latest cc65 to compile. If your not using a windows machine, you can just grab the command out of the bat file to compile.

Probably the biggest thing to adjust is the timing params, this really needs a bit more info from the board. And also confirm the I/O locations the 7220 is mapped to. If you ever wanted to sell it, let me know.

/Rob
 
Thanks for sharing that. I grabbed a copy (and found what you started from).

I am not a Windows user so I may make a proper Makefile for this when I get that far.

As of yet, I haven't reconstructed a working II+ or IIe but I'm closer as of this weekend (I picked up an empty IIe that should be working)

I am curious what the timing base is for the Grafex card. For the Dicomed Color Controller, it's probably the Q3 clock from the Apple bus.

I don't know what the register mapping is for the Dicomed box. I can see how the Grafex card maps from the C code. Given that A0-A3 go from the Apple bus into the Dicomed box, there could be multiple control addresses plus the usual D7220 ports. Lacking documentation or Dicomed software to examine, direct inspection will be required.
 
Interesting. We had Dicomed photographic film recorders at the National Center for Atmospheric Research. They had vector CRT displays and lenses to "draw" on the film (35 mm, 4" x 5", microfiche), which was then developed. They were driven from a host computer using a DEC DR-11 style parallel interface. We drove them from PDP-11 and later Sun 3 computers. I still have the source code to a simple X11 based simulator that I wrote so we didn't have to wait for the film development turn around time to do code testing.
 
erd said:
Thanks for sharing that. I grabbed a copy (and found what you started from).

I am not a Windows user so I may make a proper Makefile for this when I get that far.

As of yet, I haven't reconstructed a working II+ or IIe but I'm closer as of this weekend (I picked up an empty IIe that should be working)

I am curious what the timing base is for the Grafex card. For the Dicomed Color Controller, it's probably the Q3 clock from the Apple bus.

I don't know what the register mapping is for the Dicomed box. I can see how the Grafex card maps from the C code. Given that A0-A3 go from the Apple bus into the Dicomed box, there could be multiple control addresses plus the usual D7220 ports. Lacking documentation or Dicomed software to examine, direct inspection will be required.
Click to expand...

The Grafex card has its own 16MHz crystal on board for the pixel clock. The timing params in the program are built around this. The details on how to build it were published in Radio Electronics magazine, here is a link to a pdf of the combined articles:

And this is my reproduction. Needs a couple of tweaks, otherwise it seems to work ok.

grafex32.jpg
 
Here's the lower board from the Dicomed box, the board with the RAM and the 7220 (and lots of '299s and '273s)

1670739893260.png
 
Here's an excerpt article from the August 1982 InfoWorld.

InfoWorld_0881_SM.jpg
 
Interesting, a connection with their film recorders as a service. That's the equivalent of what we were doing at NCAR, except with NCAR Graphics or raster image files as the input to the process. I wonder if I still have the 35 mm color slides I created during the development of the raster image conversion process, guess I should look for them. Used the classic Mandelbrot set for some of them.
 
That 1982 price of $10 per slide is why I later picked up a Polaroid FreezeFrame Video Recorder. It was only NTSC resolution, but I could make title slides on my Amiga and get a stack of images for the (incremental) cost of developing a roll of slide film (under $10 for 36-38 exposures at the time).

Given the Sony A/V connector on the Dicomed box, I could achieve the same resolution with it.
 
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