Adding CV i/o

Integrations Pure Data
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Hi :slight_smile:

I want to build my first Eurorack module using Daisy and Pure Data. For this project, I need:

  • 6 knobs

  • 5 buttons

  • 8 LEDs

  • 4 CV inputs (DC-coupled, high-speed, audio-rate modulation)

  • 8 CV outputs (DC-coupled, high-speed, audio-rate modulation)

I’m interested in the Daisy Patch SM because it’s designed for the Eurorack ecosystem. However, the CV inputs and outputs don’t support high-speed, audio-rate modulation, right? And it only has 2 CV outputs anyway.

Is it possible to add an external ADC and DAC to handle audio-rate modulation? If so, which ones would you recommend, and how would that work? Via the SPI bus? Is it really that straightforward?

Thank you :slight_smile:

1 Like
2

Welcome!!

As far as I can remember, I haven’t really seen a module powered by the SM that has more than 2 CV outputs.
This is the closest thing but it uses a commercial module: Using Expert Sleepers FHX expanders with Patch.Init()

I’m sorry that I don’t have useful information for what you want to create.

2 Likes
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A note that this setup does not run at audio rate.

1 Like
4

Thanks,
Okay, never mind the audio rate.

But can I add an external DAC to Daisy Patch SM to add 8 CV (classic control-rate) outputs ?
Like Qu-Bit Bloom v2, which has multiple CV output.

And can I deal with this extra DAC into Pure Data ? How ?
Can I find some documentation for this ?

Thanks for your help :slight_smile:

5

At the moment the Heavy Compiler doesn’t have a mechanism to configure an extra external DAC.
Any tips/ideas on how to do this would be appreciated.

I wonder if it’s possible to use a demultiplexer to create multiple outputs from a single on-board DAC output.

6

Maybe can I :

  • add an external DAC to the Patch_SM SPI bus (16 bits DC-coupled)
  • make a custom JSON file to include the standard Patch_SM i/o and add the extra DAC outputs
  • Compile my Pure Data with Plugdata selecting this JSON file

Could this work ? Or is it more complicated than that ?

7

This is how the onboard DAC is configured by the board.json parser: hvcc/hvcc/generators/c2daisy/json2daisy/resources/component_defs_patchsm.json at develop · Wasted-Audio/hvcc · GitHub