[H-GEN] Vintage computing mystery

[Arjen Lentz]

Sorry I forgot bits of the decoding, more info on the PAL.

> Below the EPROM is a chip with a code starting with PAL, I think that'll be a
> programmable logic array.
> See https://en.wikipedia.org/wiki/Programmable_Array_Logic for details

Its code was PAL 20 L 8 B NC
Starting at http://www.datasheetarchive.com/PAL20L8B-datasheet.html
The actual datasheet is
http://www.datasheetarchive.com/pdf/download.php?id=213955bde8d1531151afd1f25652c763ff2ed6&type=M&query=PAL20L8B

So with that info, you'll be able to figure out what the circuit does with what the CPU code puts into the PAL.


And I just thought of something, re possible application.
You could do some cryptography with this setup, encoding and/or decoding.
Homebrew/custom hardware crypto?

On the serial port could be a modem or other device for a remote connection.
Doing live streaming encryption on the host CPU would have been painful, so this kind of setup would have made sense.

Anyhow, can't say for sure of course (the code would tell!), but I think it's a viable conjecture.
Enjoy!

Regards,
Arjen.