mwm@Okc-Unix (12/28/82)
From: Mike Meyer <mwm@Okc-Unix>
Here are the (somwhat meagre) results of my request for information on
S100 graphics boards. If somebody out there knows of a board that isn't
mentioned here, I'd appreciate hearing about it.
<mike
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This is a favorite topic of mine. Before your friend lays out the bucks, what
is the application? If you want to hack graphs, charts, and pretty pictures,
then boards are available. If you want to do higher speed stuff, forget about
finding anything for the S100 bus.
There are a number of boards available, depending on the resolution required,
whether color is required, and the amount of money one is willing to spend.
A fairly good general purpose monochrome graphics board is the MicroAngelo,
manufactued by Scion Corp. The new model (2nd generation design) provides
for two pages of 512 x 480, an on-board Z80A which does all your line and
character drawing (firmware on EPROM), and interfaces to a standard monitor
(though P39 phosphor is a must). It can also be cascaded with other
MicroAngelo boards through a color mapping board, so that a B/W system can
be expanded to color if required. Its main limitation is that a Z80 can only
draw lines, etc. at about 8000-10000 pixels/sec, so forget about doing
animation. I've been using one for over 2 years now, and it is easy to
bring up and very reliable. MicroAngelos cost about $900 or so.
There are other companies which produce similar products, though they seem more
kludgy. CDL has a similar board, and there is another company which makes
a board set called the "CAT" (unfortunately I can't remember the name of the
company). I've heard mixed reviews about these boards, and they are in the
same price range as the MicroAngelo.
Matrox, Ltd. in Canada makes a variety of S100 graphics boards. They make a
256 x 256 (actually 256 x 240 visible) as well as a 512 x 256 (512 x 240)
board. These boards are old (but proven) designs, and work quite well. I've
used both of them and they're OK, but they have no on-board processor, so
your host is stuck doing everything.
Godbout (and others) make a board which uses the Motorola 6847 graphics chip.
This board gives you cheesy alphanumerics (32 x 16, color, uppercase only),
TRS-80 style block graphics, in color, and Apple-type graphics, in color,
but less colors than the TRS-80 style modes. The chip has alot of different
modes, etc. which make is flexible for what it can do. This board is
very similar in capability to what a Radio Shack Color Computer can hack.
There is another small company (whose name escapes me) which manufactures a
board with a TI TMS9918A graphics chip as well as a GI AY-3-8910 Sound Gen
chip on it. The TI chip is a cross between the M6847 and some of the
graphics chips used in video games in the sense that you can plot lines,
etc as well as move around "sprites", which are user-defined objects.
Like the M6847, this board isn't high resolution, but it is color, and
would be suitable if one wanted to bring up Logo on an S-100 system.
There was a write-up on this chip in the Logo issue of Byte, which has
all the TMS9918A specs. The TI Personal Computer uses this chip, so your
friend could check out the TI PC if he's interested.
[Boards using the TMS9918A are available (as kits) for $ 200-300.]
A novel idea for those who want "smart" graphics is to buy something like
a VIC-20, Commodore 64, Atari 400, etc. and use it as a graphics peripheral.
I know one person who is doing this, and is quite happy with the idea.
The nice thing about it is that the standalone units usually have enough
smarts to make them usable, and they compete very well with a MicroAngelo
cost-wise.
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Try looking at the BYTE issue (July?) that details LOGO. I believe the
first article details a graphics board (<$200! [for apple]) that uses
sprites. A S-100 board is "forthcoming," whatever that means.
====================================
You might have your friend look at the S-100 board that uses the
TI-9918 chip. That's the one with 16 colors, sprites, and a variety
of other features. The 9918 has some problems (a couple of strange
effects regarding certain color combinations) but overall is pretty
neat. Your friend could throw a board together fairly inexpensively,
or can buy a complete board or kit for a somewhat inflated price.
The company selling the kit/board is:
Electronic Design Associates
PO BOX 94055
Houston, TX 77018
(713) 999-2255
They don't answer their phone much, but they do exist.
P.S. Make sure he specifies the 9918A chip if he buys the board.
The 9918 (no suffix) is obsolete.
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Oops. Forgot about the price. There may have been an increase since
the figures I have here (Jan '81), but for what they are worth:
Color video board kit with AY-3-8910 sound generator chip
(I like that chip... 3 voices, etc.): $375
Color video board kit w/o sound chip: $345
Add $100 for assembled/tested boards.
The video boards have 16K bytes of display RAM (the max the chip supports),
but no ROM. The 9918A generates composite video directly, not RGB.
I don't see why the 9928 (that's the RGB version, right?) couldn't
be substituted with a bit of hacking.
By the way, the version with the sound chip even includes an audio
amp chip and such -- pretty nicely done.
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