First post, by feipoa
- Rank
- l33t++
I've had several requests over the years requesting guidance on adding PS/2 mouse support to the MSI MS-4144 motherboard, similar to what had been presented for the Chaintech 486SPM here: Adding PS/2 mouse components to a Chaintech 486SPM
I've attaches some photos and a PDF scan to guide you. There is a typo in the PDF scan. Where you see "R140", it should read "R14". My motherboard revision is 2.1. There may be some differences with other revisions. Please check the photos carfeully.
In brief:
1) Add two 47 pF surface mount capacitors. The motherboard's silkscreen states 470 pF, however I'm pretty sure I used 47 pF because that is what is normally used on other motherboards and is what I had on hand.
2) Add a 5-pin connector at J5. The pinouts are Vcc, N/C, GND, CLK, DATA.
3) Add two through-hole inductors at L4 and L5. Most 486 era motherboards I've encountered have these in the 1-10 uH range. I normally use 2.2 uH, but I think in this particular board, I am using 1 uH.
4) Under the keyboard socket, ensure that R14 and R106 are populated. Your motherboard revision might have these components missing. My board had them already installed and were such that R106 = 4.7 K-ohm and R14 = 10 K-ohm.
5) Short R147. This connects KBC pin 36 to IRQ 12. The PS/2 mouse won't work without it. For my board, I used a jumper header and jumper, but it is a bit tricky to implement because the pads are SMD. Thus, you can just solder these pads closed, use a 0-ohm resistor, or solder on a wire.
6) Flash your BIOS to one which includes PS/2 support. See my next post for this file.
Plan your life wisely, you'll be dead before you know it.
