Hello everyone,

Some time ago I've bought interesting 286 motherboard without CPU, BIOS, and memory. Fortunately after some googling i was able to find the BIOS image here, CPU on ebay (there are still plenty of 20Mhz 286 made by Harris - very cheap), and I replaced SIPP sockets with SIMM. After setting up jumpers, according to wikipedia and adding necessary cards - board comes to life 😀

This motherboard (probably made by Biostar - according to BIOS vendor string 1223) is based on late highly integrated chipset from VLSI. There are only two chips VL82c311L and VL82c113. There are no separate RTC clock nor keyboard controller - both are integrated in smaller vl82c113 chip. After reading its datasheet, it turned out that keyboard controller can work in two modes: AT and PS2, and in PS2 mode mouse is supported !
I've looked on motherboard and there necessary pins (mouse clock, mouse data, and mouse IRQ) were unconnected.

1.) This was the first step - make the connections. I've connected vl82c113 pin 66 (mouse IRQ) to vl82c311l pin 7 (IRQ12), and soldered terminals to pins 63 (mouse data) and 69 (mouse clock) of vl82c113a.

2.) Second step is software part. I have to switch keyboard controller to PS/2 mode and enable necessary pins. This requires to clear two bits in KBDCTRL register. This ended up in little program in tasm:

1.model tiny
2
3.code
4org 100h
5
6start:
7    mov al, 01dh
8    out 0ech, al
9    in  al, 0edh
10    and al, 11111001b
11    out 0edh, al
12    ret
13    end start

Order is as follows:
- my small program
- ps2suppc.com (copyright by Rio444)
- mouse driver

I've connected directly vl82c113 pins to mouse pins (without any passive elements), this is probably not the safest way. I should look on some motherboard schematics how to do it properly, and I problably will.
Sometimes keyboard controller hangs (after ps2suppc), I don't know why.
Mouse is working fine in DOS, games, and Windows 3.1

I would like to thank Rio444 for his ps2suppc.com !