Unilab Serial Computer Module

[maniacminer]

I am wondering if anyone has any software to drive the Unilab Serial Computer Module 540.027? I just re-found it in a box of "tend to it directly" stuff...

It is very similar to the BBC Micro version 540.006 but it is driven via the serial port. Taking the back off, there's a PIC chip (512 words of code) an input and output latch and a MAX232 for RS232<->logic duties. Connecting it up to the PC I don't get anything useful from it when poking it with a couple of bytes of data from a double loop. This is the board

and this is what is on the bottom, I had tacked some wires to it a few years ago to hassle it from the PC...

any help would be appreciated, it would be fun to connect this to the Pi and run some of the 3-Chip-Plus demos from Python

[julie_m]

Does anything come out of the board's serial interface? If you have an oscilloscope, you might be able to work out the baud rate from the durations of bits. I'm guessing you probably have to give it some sort of instruction to read the inputs or set the outputs, and sending CHR$(13) at the correct baud rate should produce some sort of response. Of course, the command syntax will then need to be determined .....

[maniacminer]

Nothing much comes out, unfortunately. Given the basic nature of the PIC I assumed single byte instructions and single byte responses. I don't even know if the board is working as I don't have any others to compare against. I made a program to send every permutation of three bytes (16.7M combinations) and got nothing useful back despite running it four times with four different switch inputs. It might be easier to replace the PIC with another programmed by me...

[maniacminer]

OK, I was massively overthinking this (as usual)

It is very, very basic. Serial is 9600, 8, N, 1 - there is an identity byte array when byte=0x00 is sent and this returns four bytes 0xAA,0x02,0xC0,0x0F

The command to read the 8 inputs is 0x01 and this returns a byte representing the input states of the 8 input lines
The command to write to the 8 outputs is 0x05 with the output state in the second byte, e.g. 0x05, 0xFF will turn on all the outputs

I can't see any other commands in the communication I monitored, but it's enough to get almost any computer on the planet to be able to use this module and it can stop collecting dust on my workbench

Now to make up a cable, the two wire bodge to a 9D-Sub is precarious at best