PR650setsyncfreq(syncFreq)
Set sync frequency for source.
Passing 0 means don't use sync mode.
Passing 1 means use last sync measurement.
See also PR650getsyncfreq
8/20/10 Change error message to match command sent by this routine.
8/26/10 Better usage comment at top.
Psychtoolbox/PsychHardware/PR650Toolbox/PR650setsyncfreq.m