Portable I/O Computers Pages: Project Description
Here's the first effort, in the green ABS plastic box. ABS is really nice
for machining at home. The top of the EPROM was flush with the outside of
the case, and the lever to release the ZIF socket was accessible in the slot
so I could quickly change the EPROM for different applications. The three
keys are also flush with the top surface. Before getting very far, I
realized that what I wanted wouldn't all fit. (I didn't know about the PLCC
wire-wrap sockets yet!) The big connectors on it are DB-9, DB-25, and
DB-37. Harder to see are the 2.5mm and 3.5mm jacks for cassette tape modem,
power, and RS-232 with no hardware handshaking. The "ok{ 0 }" displayed in
Bench-1's LCD is a typical Forth prompt, saying the last operation produced
no error conditions, there's nothing on the stack., and it's ready for the
next instructions.
So I started over with a gray ABS plastic box a little bigger. Near the
middle you can see an octal DIP switch for selecting options and a bar of
10 annunciator LEDs. The slots were for plugging in C64-type expansion
boards for different projects. Below the 16-character LCD is a row
of five half-inch-square white Grayhill keys with clear removable keycaps
suitable for putting labels underneath.
Here's the same thing with the top removed. I actually got this one about
80%-90% done. I don't remember anymore why I quit working on it. Bench-1
shown above was my next effort, which became quite successful and I've used
it for scores of projects, despite its lack of such a nice, neat, rugged,
portable package.
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