The Mechatronics mouse must be plugged into the joystick port of the TI console:
mame ti99_4a -joyport mecmouse [-mouse]
As said above, use the -mouse switch in the command line to capture the mouse.
Examples for Mechatronics mouse software
These two examples can be found on the companion disk of the Mechatronics mouse.
Calculator
A simple calculator with a mouse pointer in the shape of a hand. The pointer is a sprite that is smoothly moved by the mouse. Use the left mouse button to type in a number or operation.
Breakout
This is the well-known Breakout game with mouse support. Works quite well, press the mouse button after positioning the paddle below a number to enter the game at the desired level.
TI-DOS
The third tool is a kind of graphical file manager. There are some bugs in the software, however: The program seems to be confused with 360K disks, and the mouse axes are swapped after clicking on a file.