Bugs/Issues resolved:

• The MIDI parsing/buffering code has been completely rewritten and fully meets the MIDI standard.
  New MIDI features have also been implemented (see new features).
• The external sync routines (MIDI, DIN) have been rewritten.
  The first MIDI clock is no longer missed (v1 bug), and latency is improved. The machine no longer freezes when it is synchronized to DIN (v4 bug).
  An automatic sync-selection mode has been added (see new features).
• In TRACK Program mode, a single measure can now be copied - although this function is written in the original manual, it did not work.
• The included Factory-Reset feature brings back the "Demo" patterns and tracks from v1, which had been removed on v4.

Optimizations:

• The workflow has been substantially improved.
  In PATTERN mode it is no longer necessary to stop the sequencer to juggle between PLAY and WRITE!
  It is therefore possible to modify a temporary sequence of patterns in PLAY, then edit each of them in WRITE mode, all without stopping the sequencer.
• In PATTERN TAP WRITE, the Main Keys can optionally indicate the Instrument played (the LEDs reflect the triggers of each voice) instead of the Step played.
• In PATTERN mode, the 7-segment display - so seldom used previously - now indicates the number of the current pattern (P##).
• In addition, the Display now indicates other useful information depending on the current mode, for example the Sync selection no longer indicates "0" but instead shows its textual name, e.g. "MID", "DIN", "AUT", or the Tempo value when using the Internal Clock.
• Bank changes can now be made in PATTERN mode.
  If the change is made when the Sequencer is running then the change will be effective following the last Pattern of the current Chain.
  You can also now change Banks as well as Pattern Groups without stopping the Sequencer.
• Just like the Internal Instruments, the External Instruments can also now be triggered via MIDI from your keyboard or your favorite drum pads.
• The External Instrument layer is now always accessible and is more advanced (see new features).
• The forwarding of received MIDI Voice Messages can now be disabled in the Global Options.
• The MIDI Clock output is no longer sent continuously but only when the Sequencer is playing and can optionally be disabled.
• The LED of the selected Scale now indicates the beat when the Sequencer is running, making it a permanent visual cue to the Tempo.
• The LEDs do not stop when the machine is waiting for external Sync, therefore the state of the machine can still be observed.

New features:

• The 909 now has 32 Banks instead of two. Two of the 32 Banks are still accessible from the on-board v1 and v4 Firmware.
• The 909 now includes an easily-accessible MUTE function.
  With this new feature, Internal and External Instruments can be muted as desired using the Main Keys.
  Muting and un-muting sounds disables the triggering of sounds, therefore with Internal sounds, already-triggered sounds will continue to play their envelopes, unlike when using the Instrument Level controls.
• In TRACK mode the MUTE Layer is directly accessible and MUTEs can be programmed for each Measure.
  This allows you to program progressions or variations without having to create multiple copies of the same Pattern, with more or fewer Instruments.
• An Automatic Sync selection mode ("AUT") has been added.
  In this mode the machine synchronizes to the first type of Sync received (MIDI, DIN), otherwise the Internal Clock is selected.
  This is extremely useful during composition, as the 909 can play independently of your global setup (e.g. DAW) and resynchronize with it as soon as it starts receiving Clock again.
• In PATTERN PLAY mode, a new feature called Instant Pattern Change has been added.
  This allows you to optionally switch from the currently-playing Pattern to a new Pattern instantly without waiting until after the Last Step.
• In TRACK mode, the transmission of MIDI Song Select messages can be disabled, as can the reception and transmission of MIDI Song Position Pointer.
• The MIDI Implementation has been completed!
  The transmission of System, Common and Mode messages can be individually disabled and the reception of these messages can be individually filtered.
  In PATTERN mode, BANKs and GROUPs receive and transmit MIDI Bank Select messages and MUTEs receive and send MIDI Control Changes.
  Pattern Selection also now receives and transmits on a MIDI Note range, so you can externally record and play back a jam done in PATTERN mode.
• All 32 Banks can be backed-up to your PC and restored via SysEx using the Rev.909 v5 SysEx Librarian, a Mac/Windows application.
  This software also allows "Legacy" (v1/v4) SysEx backup files to be imported, and functions as a Revolution 909 Firmware Update tool.
• The Current Bank, Global Configuration parameters as well as all Options are saved and recalled when the machine starts-up.
  The Global Configuration and Options can also be backed-up and restored using the SysEx Librarian.
• By holding certain key combinations at startup you can perform a Factory-Reset - or access the Bootloader - a special mode in which the v5 Firmware can be upgraded via MIDI.
  v5 is therefore open to other developments or fixes without ever opening your beloved 909 again!
• For those most resistant to change - which we can understand ;) - another key combination at startup will give you the choice to select v1, v4 or v5.
  Older versions are in ROM and remain executable without internal modification or addition of a selection switch.
  This also allows you to compare the 3 versions and use the Legacy SysEx, Tape and Cartridge methods (removed from v5), for backup and restoral, if needed.
• For External MIDI Instruments, the Note Mapping is no longer static, and there is now a Mapping per-Bank.
  In addition, each Ext. Inst. has is own MIDI channel/note/velocity as well as duration (note-length) parameters.
  By assigning different channels to your other drum machines, for example, you could create a 27-sound drum kit and the sequencer of the 909 becomes the centerpiece of your rhythm track! In addition there are some pre- programmed and dedicated Mappings for some other machines, such as the 707 and 727.
• This list is non-exhaustive and only indicates the major changes... You will find other small modifications here and there.

Disassembling the original code and the v5 development took a considerable amount of time! We sincerely hope you will appreciate this (R)evolution.