Psychtoolbox>Datapixx.{mex*} subfunction

Start logging TOUCHPixx touch panel activity. The TOUCHPixx controller polls the
panel at more than 5kHz waiting for a panel press. When a panel press is
detected, a touch timetag is stored with the x,y coordinates into the log buffer
specified by SetTouchpixxLog. If continuous logging is enabled, successive
timetags and coordinates are logged at 200Hz. A final timetag and (0,0)
coordinates are logged when the panel pressure is released. newLogFrames
returned by GetTouchpixxStatus indicates the number of transitions logged since
the last call to ReadTouchpixxLog.
Note that the first call to StartTouchpixxLog must be preceeded by a call to
SetTouchpixxLog to initialize and clear the log. Once SetTouchpixxLog has been
called, StartTouchpixxLog and StopTouchpixxLog may be called multiple times to
enable and disable logging.
Note that the TOUCHPixx subsystem uses some of the Digital Input resources.
Specifically, TOUCHPixx logging cannot be used simultaneously with digital input
See Touchpixx*Demo files for examples.

###See also: EnableTouchpixx, GetTouchpixxCoordinates, SetTouchpixxLog, StopTouchpixxLog, ReadTouchpixxLog, EnableTouchpixxLogContinuousMode, GetTouchpixxStatus