Beta version of firmware v0.93

I initially wanted to put in this version the support for the digital filter board, but it will take longer so I’ll keep this for v0.94 ; and with the next batch of kits coming soon, I’d rather have it tested early.

Available in:



  • A menu has been added to control the routing of the dual SVF filter board.
  • The wavetable synthesis code has been rewritten to allow interpolation between waveforms which are not contiguous in memory. This allows the definition of wavetables which are a subset, or a permutation, or a mix of the existing wavetables. 10 such wavetables have been added to oscillator 1, approximating classic Waldorf Microwave wavetables.


  • Upon reception of a program change, the active patch number is updated.


  • Removed some cruft left after the oscillators rendering rewrite of v0.92. Saved 110 bytes of code.
  • The classes and functions in the ‘hal’ directory are now an independent project called AVRil.
  • I/O pins are now referenced by port/bit rather than by an Arduino-style pin number.

What a work. Thnx

I’ll give it a try tonight - that wavetable interpolation / “new” wavetables sound tempting !

Cool, sounds great. Will give it a go tonight!


Looks good so far, I’ll probably do some more sound programming this weekend so I’ll hopefully test it extensively.

Anybody running it?

I meant to, but got sidetracked, unfortunately. I’ll get onto it, but probably not until next week, now…
Sorry about that.


Well, no extensive use for me, but I didn’t encounter any problems during the last few days running the v0.93.

I’ve been running it since the night you posted it up! Zero problems to report… All seems great so far… Actually, I had barely even tried out a lot of the .92 additions, so i’ve really been getting stuck in now :slight_smile:

yep running it … it will have pride of place at Leeds UK modular meet on June 5th… I will be videoing it as well…




…I’ve been running it too since you announced the release pichenettes. I haven’t tested it in depth yet but hope to this weekend… there is something I have just remembered I discovered on the 0.92 fw: When setting the seq clock to EXT, the groove/shuffle settings don’t work. I presume that is because they modify the clock signal and not the MIDI data? Is it possible to have the opposite?

Sorry, the groove/shuffle feature skews the internal clock - it doesn’t change the note start time ; so with an external clock all is lost. I am curious as to which sequencer/device applies the groove/shuffle by skewing the clock vs shifting the notes. On the Shruthi, It’s not possible to shift the notes, because the internal sequencer has a resolution of… 4ppqn. Note that this is not specific to v0.92 - things have been implemented like that since day 1.

I’m not sure if there are /any/ hardware sequencers or synths that skew the note start time, I just thought it would be a cool feature. I suppose I don’t spend enough time thinking about the inner workings of my magic boxes :wink: I found a really nice shuffling arpeggio using the Shruthi and wanted to sync it with some other MIDI devices to start making a tune, without having to use a fully fledged sequencer and this is when I discovered the (non) issue. It makes sense really and understand you would need a very high resolution MIDI sequencer for it to work. I think the last time I experimented with live MIDI arpeggiators was in Cubase on the Atari ST but I can’t remember if the groove was set live or afterwards with quantisation. I have also started to play with software arpeggiators on Linux so I’ll see where that gets me!