[M]ouse: A PS/2 To C64 Adapter

4100951630_8cb9dc6164 (Custom)

[svofski] has a friend who is a pixel artist. They really wanted to try out their skills on a c64, but were missing a mouse. The original mouse for the c64 was not only serial, but used a different method of communication than more modern mice. [svofski] built this adapter to translate the ps/2 data to something the c64 can use. The writeup describes the build in detail and even has the PCB and source code available for download.


[via flickr]

30 thoughts on “[M]ouse: A PS/2 To C64 Adapter

  1. If your going to go to the trouble of doing this then why not just make it for a usb mouse instead of PS2? I mean seriously it’s getting harder and harder to find a PS2 mouse every day so why replace one mouse that virtually can’t be found with one that will be the same way very soon?

  2. pluz there are still USB mouses that also work with PS2 adapters

    and USB mouse needs USB host, and USB host needs a lot of hardware/software compared to serial. There was one bitbanged project using mega32, other option is AVR with host build in ($6). Both are faster than C64 .. kinda pointless

  3. Oh hell yeah!
    I’ve been waiting for a PS/2->1351 adaptor for years.

    There was a serial->1351 adaptor before, but finding serial mice nowadays is almost impossible.

    The 1351 mouse (which this adaptor emulates), “send” the X and Y axis movement through the C64 analog paddle inputs.

  4. It’s essentially a joystick port more than a serial port. The old Tandys were the same idea with round ports. The mouse essentially had two pots that moved to the extremes of the screen. You could plug in a joystick and do the same things the mouse did without and driver changes.

  5. I did a PS/2 adapter because a PS/2 host is infinitely more simple than a USB host. A dual-standard mouse with a USB-PS2 adapter would work too, although I never tried. People who are not afraid of using a real Commodore 64 in 2009 tend not to experience shortage of real PS/2 mice.

    C64 mouse taps into analog paddle lines. It’s very simple really and it’s easier to show on a scope than to explain it verbally.

  6. cow_juice, PS/2 is not USB, for that adapter, the mouse has to be designed for the adapter. It’s the same story with trying to get a PS/2 keyboard to work.

    Look up PS/2 on wikipedia, and they will tell you that it is a serial interface.

  7. Don’t quite get the interest people have in the c64, and if I had one working and in use what I’d mod first is the lousy shielding, how that thing ever got through the FCC I’ll never know.
    Its shielding was a piece of thin cardboard with aluminum foil stuck to it, for those that don’t know. and if that wasn’t bad enough it just folded along the length over the top but left 3 sides open.

    1. Actually. Pins 5 and 9 of the Amiga Joystick port are analog inputs. On digital joysticks these are pulled high (5vdc), and go low (0vdc) when buttons 2 and 3 are pressed. Pins 1-4 are the four directions Pin 7 in +5vdc and Pin 8 is ground. When using PADDLES

    2. On the C64 Pins 5 and 9 are analog inputs. When using digital devices these are read to see if they are high or low to indicate button presses on buttons 3 and 2 respectively. When used with analog devices are used, the 4 directional up, down , left, or right (Pins 1,2,3 and 4 respectively) are used for buttons, in order for pins 5 and 9 to be used analog directional inputs. Inside the computer these 4 analog inputs (aka pins 5 and 9 of both joystick ports) are sent to a 4066 chip which contains 4 analog switches which selectively connects one or the other post to pins 23 and 24 of the SID chip. These are analog inputs into the SID chip. So I looked at the Amiga These 4 analog input existed in the Amiga 1200, and I suspect also in other Amiga’s. In the Amiga 1200 these go to U# which seams to be called the PAULA chip and are labelled as still being Pots X and Y. Pot is short for potentiometer which is the variable resistor inside of paddles and joysticks. There you are incorrect in you assumption. The Amiga’s were built are technically Commodore computers, Amiga’s were built under the Amiga name, but were manufactured by Commodore, so why re-engineer an elegant and working interface. So yes Amiga’s do have a analog inputs on they’re Joystick ports. Here is the schematic:


  8. >PS/2 is serial, but it is NOT standard RS-232.

    RS232 != “Serial”. RS232 is a “type of serial communications protocol”. SATA is serial, doesn’t mean you can plug a “serial mouse” into it does it?
    Even if PS/2 was RS232 compatible, RS232 only defines low level stuff like signalling levels, data representation, so two “RS232 mice” for different platforms could use totally different protocols on top of RS232, so you would still need some sort of translation.

    >Graham Simpson

    There have been PS/2 -> Amiga mouse adaptors for yonks. I think there have been schematics up on Aminet for the best part of a decade. Individual Computers have also produced all sorts of similar stuff over the years,..

  9. Actually, it really isn’t so much of an issue of who’s interested in the FCC as it is whether or not the FCC is interested in YOU.

    @svofski said: don’t quite get the interest people have in the FCC.

  10. @McSteez & therian

    The mouse may look a bit goofy with the cable pointing vertically but I work on a small desk with plenty of desk fodder around, and one of the most annoying things is the bend in the mouse cable when it pushed up against something.

    I would like to have one of these mices :)

  11. Lol, it’s not the FCC that I care about but rather the radio interference that gets into my stuff.
    It just seems so incredible it was approved.
    No ‘white space’ within 30 yard of an c64 I can tell you.

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