Getting a PS/2 mouse to work in joystick emulation mode on the TI-99/4A.

[Dexter]

In this thread I got the idea on how to get a PS/2 mouse, or anything alike, to work on the TI-99/4A as if it were a joystick.

http://atariage.com/forums/topic/231274-stuarts-ti-994a-internet-web-browser/?p=3201227

 

It might be possible with an adapter called: "Micromys V4".

 

http://www.vesalia.de/e_micromysv4.htm

http://www.protovision-online.com/hardw/micromys.php?language=en

http://www.micromys.de/

 

The Micromys can convert an incoming PS/2 mouse signal to Commodore compatible joystick movements. This can be done by holding the right mouse button during powering on the device.

 

There is also a touchpad with PS/2 interface:

http://www.ergocanada.com/detailed_specification_pages/cirque_corporation_easy_cat_ps2_or_serial_touchpad.html

 

Of course being new to the TI, I didn’t know of its strange joystick interface. So after looking a bit deeper into it, I found a few hurdles:

 

1 The TI has no Commodore compatible joystick port. At least I knew that much.

2 There is no power for the Micromys on the TI joystick port.

3 How to get the Micromys in Commodore joystick emulation mode.

4 There are two Micromys versions, V3 and V4.

 

1 The first issue is easily solved with an Atari <-> TI joystick adapter. I finished it and it works fine. Found it on this site:

http://www.mainbyte.com/ti99/hardware/cables/joystick.html

 

2 Secondly, what I didn't know was that the TI joystick port doesn't have GND and 5V. This is necessary to power the Micromys.

Fortunately I found a mod to get power on the two unused pins of the joystick port.

http://www.unige.ch/medecine/nouspikel/ti99/joystick.htm#modifying%20the%20port

Unfortunately pin 2 and 7 on the TI joystick interface is the common GND signal on the two Commodore joysticks on their pins 8.

There is another mod, which could be useful.

http://www.unige.ch/medecine/nouspikel/ti99/joystick.htm#circuitery

 

3 To get the Micromys in Commodore joystick emulation mode, I have to set the dip switches on my version 3, and hold the right mouse button while powering up.

 

4 Micromys V3 isn’t available anymore, now it’s V4 which has no dipswitches anymore. It auto detects the interface on the pins voltages I guess.

After reading all information, it seems one can turn off auto detection and set it to Commodore mode only.

 

So I went on and took a battery and connected it to pin7 +5V and pin8 GND.

While connecting the battery, I held down the right mouse button.

 

What can I say, with Micromys V3 it WORKS! I played TI Invaders with it, and it works quite stable and precise. I couldn’t be more satisfied with the result. I used the battery, because the consoles ground can’t be connect to pin8 directly.

 

Without having tested, Micromys V4 should also work when turning off auto detection.

 

[Omega-TI]

I love this idea, and the small things like supplying power can be overcome, but I have one question that's nagging me at the moment, only because I'm ignorant about the Commodore in general, but are the Commodore joysticks digital like the TI's or are they analog?

[Dexter]

Yes, they are digital, as far as I know, they are exchangable with the Atari joysticks.

Here is the pinout of the two joystick ports of the Commodore 64.

Edited March 26, 2015 by Dexter

[Omega-TI]

Yeah that makes total sense. I don't know why I even questioned it... I guess going so long without sleep played a part. Damn, after work tonight I'm not going to be hanging out here... I'm going to crash instead. I feel rather foolish having posted that. Right now it's COFFEE TIME!!!!!