most of the semi-automatics I have come across have a selector for wash or spin, and a timer for how long you want it to complete that one task....
not fully automatic.....
you would set the selector for wash, and turn the timer for lets say 10 minutes, and when the timer ran out, the wash action would stop, waiting for your next task, wash again, or select spin, and reset the timer, filling may also be an option, or you may have to do that manually...
as for an automatic.....you would set the timer/cycle selector, and walk away...the machine would fill, wash, spin, fill, rinse, spin...with almost no help from the operator
I kinda did this with an automatic once, I put a switch in-line of the timer's motor, and turned off this motor if I wanted a longer wash, or spin....although the timer could not be set to turn off by itself, I had to keep track how long I was letting it perform its task....or plug it into a wall outlet timer