Zynaptik Extensions

Hi @zynthianers!

I’ve very good news for those of you that love to hack the wires …

Zynaptik Extensions are finally implemented (although not fully!)

  • Extra MCP23017 => 16 extra digital I/O that you can use as customizable switches
  • ADS115 => 4 Analog Input that you can assign to MIDI events, like PitchBending, CC or ChanPress.

Analog output ( MCP4728) remains unimplemented yet …

Here the details:


Of course, you have to update your zynthian :wink:



The magical number 16…
Let’s remember where we already have seen it…
16… is it not 8 banks of 8 presets, or snapshots, which can be called rapidly from the front panel ?
Is it not 16 steps of a drum machine pattern ? @riban 's step sequencer in sight…

16 I/O switches, does that mean 16 in and 16 outs ? In that case each push button could be equiped with a LED ?
Or does that mean 16 I/O and, for each of them, you have to decide if it’s an in or an out ?

16 input/output total. But currently only input is implemented in zyncoder library, what allows to use it as customizable switches that can be assigned to:

  • MIDI messages => CC switches, Note-On, Program Change, etc.
  • CUIA (Callable UI Actions)

We could develop a similar mechanism for output, a kind of AUIF (Assignable UI Flags) …


That’s a great improvement…
Would that lead to a new case ?
(And btw, is this new feature compatible with Zynthian 3?)

Of course, it’s fully compatible with v3 kits. Everybody having a zynaptik circuit can benefit from the new Zynaptik Extensions by simply soldering the extension submodules on the zynaptik module:

Buy MCP23017 DIP
Buy ADS1115 module

We are working for offering “Zynaptik Extension Kits” on the zynthian shop …



You might note the V4 case has a cutout for the ribbon cable in the front.

hmm … the led indication would obviously come in handy … :wink:

Yes, v3 cases doesn’t have this cutout, but it’s an easy task. I’m pretty sure that people that doesn’t fear of soldering the submodules won’t be afraid of cutting out the case with a “dremmel” :wink:


Any proposal for the list of AUIFs (Assignable UI Flags) to be implemented?
For instance:

  • Headphones on/off
  • Single Channel Mode on/off
  • MIDI clock on/off (*)
  • MIDI Network on/off (QMidinet/RTPMidi)
  • XRUN (*)

But the most interesting ones (*) are already displayed on the status bar, and the rest don’t seem too interesting …

I’m pretty sure you will light my mind …


Backlit buttons?

As implemented on popular midicontrollers…


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Gui heartbeat?

I think that on a small screen, a large number of small characters is evil, if you mean that you plan to place additional characters on the screen.
It seems to me that a page in the web interface will be enough to indicate and visuality which button is assigned to which function.
But what I would really like to see is a physical implementation of button highlighting, and the function name can be printed on self-adhesive paper and pasted next to the button.

As for what functions should be available for selection, it seems to me that there is already quite enough.

it is quite logical to manage all this from the Zynthian menu.

If I had buttons (and it seems I now can :smiley:) I would set them up as “quick access” buttons to different screens. Something like:

  • Layers screen
  • Audio Recording screen
  • ALSA Mixer screen
  • Step Sequencer screen

I’m thinking I should get some pushbuttons and see if I can’t do this…

Hi @Jtunes! Having 4 extra buttons are a possibility for everybody having latest v2 or v3 kits:


and of course these 4 buttons are included out-the-box on v4 kits.

Zynaptik allows to add more buttons and also analog inputs, what i think it’s the most interesting point …


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Would be good to dedicates some screen real estate at the bottom (similar to the top bar) to have some text showing what the current quick button functions are define for a particular page. Probably should have some sort of shift function with one of the knobs and then you have 8 quick access functions.


Currently the 4 custom buttons are not contextual and always have the same action defined …