Assembling the PS2 to RS232 Serial Mouse Adapter
44I assembled and tested the PS/2 to RS232 adapter from matze79. It allows you to use a modern PS/2 mouse on a retro machine lacking a PS/2 port by translating to the serial RS232 protocol.
Older PS/2 mice came with this capability built in, but new mice lack this feature and won't work with a simple mechanical adapter.
Note: I needed to use a different flashing command in the end. Here is the correct order: first set the fuses, then flash the firmware. The actual avrdude commands are as follows:
avrdude -c usbasp -p t2313 -U lfuse:w:0xfd:m -U hfuse:w:0xdf:m -U efuse:w:0xfe:m
avrdude -c usbasp -p t2313 -U flash:w:ps2adapter-noboot-tiny2313.hex
You need to supply power to the board via the 2.5mm socket. That socket is center negative, which is uncommon in Europe, but common for PSUs of Japanese products. E.g. SEGA and Roland devices usually have center negative supplies. Check the polarity! The PSU I used had 9V. But anything up to 12V should be fine.
Alternatively you can hook the thing up to the ATX/AT PSU in your computer, by building a cable using 2.5mm and Molex connectors, salvaged from spare cables.
Connecting to the I/O card will happen via either the DB9 port directly or via the 4-pin header on the PCB.
Project homepage: http://www.retroianer.de/ps2.html
github project: https://github.com/matze79/PS2-Adapter/
Avrdude homepage: https://www.nongnu.org/avrdude/
MacOS homebrew: https://brew.sh
USBasp clone on eBay: https://ebay.to/2P4o1EL