Connect PS/2 mouse to X68000 with circuit as simple as possible.

 

Parts list

U1	PIC12F1822 or PIC12F1840	1
R1, R2	Resister 330ohm	2
C1	Capacitor  100nF	1
X1	mini DIN 6p jack	1
X2	mini DIN 5p cable	1
	（The following parts are optional)
R4, R5, R6	Resister 100ohm	2
P1	Polyswitch 200mA	1

The mouse connector on the X68000 side is a mini-DIN 5 pin, but the cable with the male connector is not readily available. Also, if you purchase and use only the connector, depending on the connector, the cover may interfere with the X68000 main body and it will not stick it well. Do your best and procure 😛

Please be aware that you can connect  both keyboard connector and mouse connector when unwanted pins on mini-DIN 6pin cable are folded. (So I don’t recommend this method much)

I think there are no parts that are difficult to buy. If it is accessible to Akihabara in Japan, it will be available at all stores. PIC12F1822 can be purchased at Akizuki-Densi, Poly-switch can be purchased at Sengoku-Densho or MARUTSU.

The poly-switch fulfills the role of a fuse when 5V and GND are short-circuited. It will self-recover if short circuit disappears. I think that 200mA is sufficient, but please match it to the PS/2 keyboard to use.

 

Schematic

It works without PPTC (PolySw). I put it just in case.  Please don’t make the cable connecting X68000 and this adapter too long.

 

Example

Prototype using breadboard.

 

I designed and manufactured the PCB and made it. The MCU for keyboard conversion is also implemented together.

 

By using a PS/2 splitter cable, you can convert both keyboard and mouse with this one adaptor.

 

Fiwmware

1.1 20210806	ps2ms_x68_20210806.zip Fix the problem that PS/2 & USB Compatible mouse dose not work properly.
1.0 20171213	ps2ms_x68.20171213.zip First edition