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A project log for STEbus 80C188 with parallel I/O (SC88PIO)

80C188 processor board documentation

keithKeith 06/03/2024 at 20:520 Comments

2024-05-29 Someone has one of these! Looking forward to taking some pictures, reading the ROM and analysing the PAL chips.

2024-05-31 Board purchased, should arrive next week.

2024-06-03 Boards arrived! Some leakage residue around battery location. Removed the small battery, gave it a quick clean with IPA then photographed both sides.

Inspection shows it is a version 2 issue 2 board. This differs from the catalogue photo. The CPU has changed from NMOS to CMOS, so it no longer has a heat sink and is in a PLCC package.  The newer board has an oscillator in a DIP14 metal can, and the battery was replaced by a much smaller one.

Not too much visible damage - a few tracks are a bit corroded. We shall soon see if the board works or not.

2024-06-08

I don't have an 8086 disassembler, assembler, or the time to reverse engineer it. I have uploaded an assembler source file of bytes and ASCII strings. This helps identify which bytes are text and not instructions. 

There is a assembler demo program in the manual. It initialises the board but does not demonstrate the parallel I/O.

I can't think of an interesting application for it at the moment.

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