Thanks,
Chris
Wow! That brings back some memories!
I still have one of those "tank game" circuit boards stashed away
somewhere. Now If I could find it and hook it up to a TV... I seem to
recall that it had very basic shapes. The tanks were like squared off
"Y" with the gun being the leg of that "Y".
I also recall a shooting game which has a photo cell pistol and there
were several selectable games where the player had to shoot a square
moving on the screen. I don't have that one anymore.
Peteski
Although your enquiry is about how far they took TTL logic, I must say
I am impressed at what Computer Space did waaaay back in 1971. I run a
site dedicated to Computer Space and there's schematics, screenshots,
and lots of details about that game if you're interested.
www.computerspacefan.com
I am amazed Nolan Bushnell and Ted Dabney got nearly Asteroids quality
graphics and gameplay using no CPU at all and doing the whole thing
with just TTL.
_Radio-Electronics_ magazine published these articles in 1978 and 1979. One
was "Tank," and the other was the "jump-the-motorcycle-over-the-buses" game.
More data on the individual I.C.'s:
General Instrument AY-3-8760 was a 28-pin DIP chip for the motorcycle
video game. It featured on-screen scoring and included four game
variations: "Drag Race," "Enduro," "Stunt Cycle" and "Motorcross." It was
designed for both color and B&W operation. You had to hook up a power
supply, an audio amplifier (the sound came out of the chip itself and was
not fed directly to the TV), and the input switches. There was a video
output signal that could be connected to a composite video monitor, but if
you wanted to hook it up to the antenna input of a TV set, you had to feed
that video signal into an RF modulator.
The Tank game used a General Instrument AY-3-8700-1 chip, a 28-pin DIP --
OR -- a General Instrument AY-3-8710-1. Same stuff applies as the chip
above.
http://www.pong-story.com/gi.htm
I even have a system with card games (Champion 2711) that have these games
on a single GI chip (AY-3-8800).
These are the "roots". :)
Nico
Sap1
"Matt J. McCullar" <mccu...@flash.net> a écrit dans le message de news:
07xal.10210$W06....@flpi148.ffdc.sbc.com...
- Trevor
> shots of the games. I'd really like to see how far they took TTL
> before eventually moving to cpu based reprogramable units like the
> 2600 and the fairchild channel F. From descriptions I've read, some
I don't think there were too many (if any) TTL-based (as in only using
generic 74xx chips) home games simply because of the sheer number of
chips involved, especially with non-pong games. The cost to make complex
TTL-chip games would have been high enough that only coin-op machines
could justify the expense. It was only when single-chip versions were
made that the Pong clone market took off.
As for how far they took single-chip games, offhand I can't think of any
other than pong, breakout, tank, and stunt cycle. However, the 2600's
Stella chip is really the final evolution of the discrete-logic design,
with a CPU added to do the custom stuff, as well as being responsible
for the vertical sync counting. In comparison, the other programmable
systems were "standard" bitmap/tilemap/sprite designs.
I have a thick (like 3cm) Tab Book about making various kinds of games
using just TTL. The basic principle is to have the video sync circuitry
drive lots of counters and comparators and registers, with small PROMs
for bitmap images like tanks and motorcycles. And naturally, what you
could do with discrete chips could also be done with single-chip custom
silicon, what we call ASICs nowadays.
If it weren't so much easier to make games with software than with
hardware, I could see those principles being applied to VHDL / Verilog
implementations that you could load into an FPGA.
I just looked for a picture of the guts of the Odyssey I and was stunned
to see how primitive it was. This isn't just pre-TTL, it's pre-IC. It's
full of little plug-in modules with transistors and resistors and
capacitors all over. It's amazing that they got that jumble of parts to
do as much as they did. See for yourself:
http://www.binarydinosaurs.co.uk/Museum/Magnavox/odyssey.php
> I have a thick (like 3cm) Tab Book about making various kinds of games
> using just TTL. The basic principle is to have the video sync circuitry
> drive lots of counters and comparators and registers, with small PROMs
> for bitmap images like tanks and motorcycles. And naturally, what you
> could do with discrete chips could also be done with single-chip custom
> silicon, what we call ASICs nowadays.
I've got a copy of that book, too. It does make for interesting (though
sometimes tedious) reading. Only problem is, TAB was notorious for their
electronics books being riddled with errors in their schematic diagrams and
I learned the hard way that I had to read their stuff with a grain of
aspirin.
> I just looked for a picture of the guts of the Odyssey I and was stunned
> to see how primitive it was. This isn't just pre-TTL, it's pre-IC.
I'd love to get my hands on one of those! I'd heard it was a bunch of
discrete components. But it wasn't bad for the period. I think Magnavox
actually did offer at least one model of TV set that had the Odyssey built
into the set itself as an extra feature... I think I read that in an old
magazine ad. Magnavox was famous for high-end gadgets like that. My family
once had a usaed Magnavox TV set that had a motorized analog tuner; I think
in the past it had once had an ultrasonic remote control so it could change
channels, but we never had the actual remote control... but there was a red
button on the set we could push to make the tuner change channels all by
itself. As kids, we found this endlessly entertaining, though it was very
tricky getting the "roulette wheel" to stop on the channel you really
wanted.
Another one of our garage-sale conquests over 20 years ago was a genuine
Odyssey game system. It had one flaw: it didn't work. It cost us only a
few bucks, so we probably just trashed it. Now I wish we'd kept it so I
could study it. I remember all of those plastic overlays and plug-in carts
that came with it.
> Another one of our garage-sale conquests over 20 years ago was a genuine
> Odyssey game system. It had one flaw: it didn't work. It cost us only a
> few bucks, so we probably just trashed it. Now I wish we'd kept it so I
> could study it. I remember all of those plastic overlays and plug-in carts
> that came with it.
The schematics are available, so had you kept it, you could now repair
it. Pity.
jt