Sb: #Trackball Info
Fm: Frank Hausman 71251,2002


Atari TRAKBALL:  In TRAKBALL mode.    Here's what I've learned about the
data from TRAKBALL mode:
    Bit    Function
     3     Clock for vertical motion
     2     Direction:  0=up, 1=down
     1     Clock for horizontal motion
     0     Direction:  0=left, 1=right

It's a good idea to sample the trackball VERY FREQUENTLY to avoid missing
clock transitions, and causing non-linear responses.