Sharp

Firmware source and schematics for the Sharp Dual Arpeggiator

This is a Teensy 4 based Arpeggiator with a number of special features:

• Multiple basic modes
  • Range of 1 to 4 octaves
  • Standard up, down and up+down
  • In, out and in-out
  • Random and shuffle
• Variations on the basic modes
  • Repeat every note, every 2nd note, every 2nd note after the 3rd note
  • Play each note over all octaves before proceeding to the next note
  • Double play at double speed the first or last note in the pattern (ratchet)
  • Random walk (small random chance of stepping backwards each step)
  • Half speed chord mode (up to 3 notes in the chord - highest, lowest and one in the middle)
  • Swing beat
• Optional rounding to a timebase of 2, 3 or 4 to ensure the notes played in a cycle fit to a desired multiple
• Latch notes so they don't need to be held down
• Cycle the pattern notes in either note order or played order
• Optionally apply a tempo increase or decrease factor of 2, 3 or 4 to the arpeggio
• Split the keyboard into arpeggiated and not-arpeggiated sections
  • choose any note for the split point
  • arpeggiate either the upper or lower section
  • send both sections to MIDI channel 1, or lower to channel 1 and upper to channel 2
• Support 5-pin MIDI in and out, as well as USB MIDI (as a class compliant host)
• Provides pitch and gate CV outs for integration with modular gear
• Record and replay (transposable) MIDI

Dual Mode

However, the most interesting and important feature is Dual mode.

• Manage two arpeggios at once
• Each arpeggio is driven by the same held notes
• Arpeggio 1 is sent to MIDI channel 1 (and pitch/gate CV 1), and arpeggio 2 is sent to MIDI channel 2 (and pitch/gate CV 2)

Modes and variations

Listen:

• the Standard Modes
• the Alt Modes
• some simple dual arpeggios
• a more complex dual arpeggio demo (still comes from just playing a few chords).

Finally, here are some examples of the modes and variations as notation.