Just think of this for the machinedrum uw and it works.
take a sample ,( not too short)
set the following parameter:
-start 64
-dec 127
-hold 127
add a square lfo on end parameter, trig mode, depth to 127
play the sample, if the speed of the lfo is not too short the sample will play and never stop,
YOu can now play with the speed for granular effect ...