There are many ways to go with the EHX 8 Step Program covering the EXP PED parameters. I'll confine the discussion here to what can be done with PLY-START automation. We'll leave out Preset changes, Preset Cues, and omit the extensive MIDI control available (for virtually every 8 Step Program parameter). More information here.
Part 3 – Automated PLY-START via Expression
Tempo Control – Control the speed of the PLY-START position changes with MIDI Sync and Tap Divide, or asynchronous with the Rate slider, Tap, Tap Divide, or 'pass-through' Expression Pedal.
MODES (preset operations)
Depth – Normally set to 5 for Eventide pedals, but that value can be proportionally trimmed back with the 'pass-through' Expression Pedal. Depth over 5 effectively brings up all slider positions towards maximum.
Glide – The time is takes to go from one PLY-START position to the next. The range is 0-9; from an instant jump to slewing through all values between one PLY-START position and the next (slider).
Direction – Forward, Reverse, Bounce (Up and Down; inclusive or exclusive), and Random PLY-START locations. This (and other) parameters interact with most other current Play Mode and Mode values.
Sequence Length – Active sliders 1-8. It can be useful to limit the number of PLY-START positions, and control the locations with virtual LFOs [square, triangle, sine, ramp, sawtooth].
PLAY MODES (triggered by Play switch)
Loop – The 'normal' mode for sequencing through the sliders, then repeating. The actual results are highly dependent on the current Sequence Length, Direction, and related parameter values.
1 Shot – Plays the sequence straight through once, with no loopback. This is great for a burst of PLY-START positions that returns to the starting point.
Show More...Step Thru – Each press of the Play switch shifts to the next PLY-START position. Control over the 'grain' sequencing by foot switch. It will return to the initial point and step through the current sequence again.
I'm sure that I missed a few items. One note for MIDI users: The 8 Step Program responds to MIDI Sync, plus Start (Continue) / Stop commands, which mirrors the H9 / TimeFactor Looper implementation. It's a perfectly synchronized pairing. For a little more info on Looper MIDI control (that I really need to update), check out this thread.