Arturia KeyStep - Controller / Sequencer - Manual (Page 21)

2.3.6. Hold button
When the Hold button is lit you can lift your fingers off the keys and the arpeggio will keep
playing. It will keep running until you play another note or chord, at which point the new
note(s) will become a new arpeggio.
You may add as many as 32 notes to your arpeggio as long as you continue to hold down at
least one key. The notes you play will be added to the arpeggio at the nearest time division
increment.
The same rule applies with large arpeggios: once you release all of the keys the arpeggio
you have constructed will continue to run until you play another note or chord.
For even more in-depth coverage of the arpeggiator see chapter 5 [p.32] .
Arturia - User Manual KeyStep - Basic Operations 16