TR9090, sequencer anyone?

No actual progress on the drum synth itself, but instead I’ve been toying around with a sketch for a sequencer. As TR9090 is a plain sound module, adding a sequencer would make it more faithful to the original 909. More importantly, much more self-contained and ‘hands on’.  Modifying something out of the MBHP platform would provide a relatively straightforward solution and maybe even I, the less programming oriented, could manage this. Heavy emphasis on the word ‘maybe’ ;) .. Here’s what I’ve been planning feature-wise:


  • Menu encoder with integrated button (ie. Inc/Dec Value + OK/Cancel).
  • Tempo adjustment  knob + tempo LED.
  • Shuffle amount adjustment knob.
  • Standard buttons; Play, Stop/Continue, Edit/Store, Flam On/Off, Instrument Select/Mute.
  • Buttons with LEDs; Shuffle On/Off, Pattern Select, Pattern Length, Steps 1 to 16.
  • Five buttons under display for menu functions.

Play Mode functionality

  • Default mode on power up.
  • During playback, the according step is indicated with the Step LED.
  • Select LED lit.
  • Play individual drum sound with default velocity: Press Step buttons 1 to 11.
  • Mute individual drum sound: Press Instr Select/Mute + Step buttons 1 to 11.
  • Tempo: Freely adjustable using Tempo knob or press Step 16 repeatedly for tap tempo.
  • Pattern select: Press Pattern + Step 1 to 10. Should change when the last digit has been input and the current pattern finishes playing. Or maybe user-selectable behaviour?
  • Play Mode: Step 12 = Forward, Step 13 = Reverse, Step 14 = Ping Pong.
  • Shuffle: Freely adjustable, enable/disable with Shuffle On/Off and adjust to required swing amount.
  • Flam: Enable/disable with Flam On/Off. Flammed steps are selected in editing mode.

Edit Mode functionality

  • Should be accessible without stopping/interfering playback.
  • Length LED lit.
  • Edit/Store: Enable edit mode, press second time to store changes and return to play mode.
  • Drum sound select: Press Instr. Sel/Mute + Step 1 to 11. Display should show the name of sound to be edited as long as Sel/Mute is held. Repeated presses on same Step button should trigger the sound (?)
  • Step On/Off: Once sound has been selected, press Step 1 to 16 to enable/disable given step, LED lit for enabled steps.
  • Velocity: Press and hold Step 1 to 16, adjust value (from default) using datawheel.
  • Flam: Press Flam On/Off + Step 1 to 16 to enable/disable per step, LED lit for enabled steps.
  • Pattern Length: Press Pattern + Steps 1 to 16.

Menu  Functionality

  • Menu/Cancel selects menu on/off
  • Values defined by datawheel or by Step buttons.  Possible to use combination of both?
  • Play Mode: Possible menu buttons Copy, Paste, Sys, Load, Save.
  • Play Mode sub menus: Copy/Paste could contain Pattern/Vel/Flam/All. Sys could contain Midi channel selection for TxD / RxD separately, clock selection (int/ext) and value for defaul velocity.
  • Edit Mode: Possible menu buttons Copy, Swap, Paste, Clr, Func
  • Edit Mode sub menus: Copy/Swap/Paste, same as Play Mode. Func should contain at least Randomize, Shift pattern left/right functions.

So nothing too complex feature-wise, make it performance oriented above all. So, no deep menus and complex modifier button combos. I even bothered doing a sketch of a possible layout. MSPaint FTW \:D/

TR9090, sketch for a possible sequencer layout

Should be self-explanatory at a glance, the red dots and numbers are LEDs.

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