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Mini-ITX PC in an Atari 800
tgeller writes "As case mods go, this one's not the weirdest, But it has its own retro charm. Musician and geek Andy Hutson slipped a Mini-ITX motherboard into an Atari 800 case... and used an old cartridge as the mouse! Too bad the original keyboard's not functional." This almost makes me want to tear apart my old Apple //c and see what I can make. Almost.
Ok, so putting a modern PC in an old computercase is cool and all, but running modern style software on the actual old computer is much cooler! Check out the Contiki operating system for such old computers (including the Atari 800): it is a multi-tasking graphical operating system with full Internet access (web browser, telnet client, web server!) that runs on a a bunch of different old computers. They even have a web server running on a real Commodore 64.
The guy did not even bother to break out a multi meter and figure out how the oldkb worked.... btw all the good stuff is at www.mini-itx.org
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I don't think so!!!
I am not sure about the Atari keyboard, but I had a Z80 Spectrum +2. The keyboard was not a serial port sending characters sequentially, it was implemented using parallel inputs. I guess you would need a microcontroller to convert the Atari keyboard to a PS2 keyboard.
Mini-ITX site has a lot of links to similar projects:
http://www.mini-itx.com
The Atari itself, if it were working, would undoubtedly have some sort of circuitry that would take the keyboard inputs and stuff them into a buffer of some sort. One would have to know the format of this buffer (ASCII characters maybe?) and then convert them into PS/2 scancodes and stuff those into the ITX's keyboard controller chip. This would undoubtedly require some kind of specialized chip. I'm not a hardware hacker, so I wouldn't be able to do it, but I know people who *would* and I at least understand the theory, or I think I do anyway. (I'm sure someone will correct me if I'm completely talking out my ass.)
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The way any keyboard works is that it makes a short-circuit between two points. In all PS2 keyboards, there is a microcontroller that detects these short-circuits and then sends a "packet" serially to the computer based on a truth table.
Therefore, it would be dirt easy to take appart an old PS2 keyboard, rip off the microcontroller inside and solder the proper "wires" to it so that when a button is pressed on the Atari keyboard, the microcontroller "knows" which letter has been pressed.
The only "hic" here is if the matrix of wires composing the keyboard would differ from modern keyboards. This would be very doubtful as technology tries to be backwards compatible.
The Atari I/O chip (POKEY, for POrts and KEYboard), was fed a row/column matrix from the keyboard, and then read directly by the CPU.
In order to make the keyboard compatible with a PC, you would need a microcontroller that scanned the row/column matrix and then generated the serial data stream that a PC's 8042 keyboard controller wanted to see.
Not really a very difficult task for a hardware guy - a PIC would probably do quite nicely.
I wonder if the guy was able to use the interior potmetal shield of the Atari - the 800 was designed back when "Class B computing device" MEANT something - Atari took no chance that the computer would fail to pass FCC regulations. The 800 was the quietest (in the RF sense of the word) computer I'd ever seen - ANYTHING that could generate RF was on the inside of a eight-of-an-inch thick metal box.
But using a Star Raiders cart as a mouse?!?!
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