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https://github.com/polykit/pico-dco
Polyphonic Digitally Controlled Oscillator (DCO) controlled by Raspberry Pi Pico PIO
https://github.com/polykit/pico-dco
dco kicad midi oscillator pcb pico-dco pio polyphonic polyphony raspberry-pi-pico schematics sdiy synthesizer vco
Last synced: 3 months ago
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Polyphonic Digitally Controlled Oscillator (DCO) controlled by Raspberry Pi Pico PIO
- Host: GitHub
- URL: https://github.com/polykit/pico-dco
- Owner: polykit
- Created: 2021-04-23T19:42:09.000Z (over 3 years ago)
- Default Branch: master
- Last Pushed: 2023-03-25T18:19:55.000Z (almost 2 years ago)
- Last Synced: 2024-10-31T09:50:18.846Z (3 months ago)
- Topics: dco, kicad, midi, oscillator, pcb, pico-dco, pio, polyphonic, polyphony, raspberry-pi-pico, schematics, sdiy, synthesizer, vco
- Language: C
- Homepage:
- Size: 4.36 MB
- Stars: 123
- Watchers: 5
- Forks: 15
- Open Issues: 2
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
# Raspberry Pi Pico Polyphonic DCO
This repository contains source code, schematics and PCB for a digitally controlled oscillator (DCO) with up to 6 voices which are driven by a Raspberry Pi Pico. It uses PIO to generate a highly accurate frequency which is controlled by USB or serial MIDI. The analog oscillator part is based on the Juno 106 and generates sawtooth and square wave signal with a 10Vpp amplitude. Amplitude compensation is done by a smoothed PWM signal coming from the Pico.
## Key features
- Digitally controlled analog oscillator using a Raspberry Pi Pico
- Up to six voices
- Voice stacking
- Detuning of voices
- Frequency modulation (FM)
- Separate gate signal
- DIN MIDI serial input
- USB MIDI input
- MIDI pitch bend
- Portamento with adjustable speed
This is how it sounds: [Ramp sample](https://soundcloud.com/polykit/pico-dco-ramp) [Pulse sample](https://soundcloud.com/polykit/pico-dco-pulse) [Polyphonic sample](https://soundcloud.com/polykit/pico-dco-polyphonic)
I use the DCO in my Polykit-6 polyphonic synthesizer, see https://www.youtube.com/watch?v=vj-DSh6yfM0 and https://www.youtube.com/watch?v=go1mErOdtsU
## Schematics and PCB
Gerber files for the PCB can be found [here](kicad/plots).
## Installation (simple)
Press `BOOTSEL` button on the Pico while powering it with USB. Copy file `build/pico-dco.uf2` onto the USB mass storage device.
## Usage
After installing the Pico should register as USB MIDI device. Alternatively serial MIDI input is available. The DCO listens to note on/note off messages on MIDI channel 1. Pitch bend is also supported. Portamento can be enabled by MIDI CC message #65, portamento time can be adjusted by CC message #5.
## Detuning, stacking and FM
The build-in analog-to-digital converter can be used to modulate these parameters. You can add an external control voltage (0-3.3V) to that input pins. These features can be disabled by commenting (`//`) the following lines:
```
#define USE_ADC_STACK_VOICES // gpio 28 (adc 2)
#define USE_ADC_DETUNE // gpio 27 (adc 1)
#define USE_ADC_FM // gpio 26 (adc 0)
```
## References
https://blog.thea.codes/the-design-of-the-juno-dco/
https://electricdruid.net/roland-juno-dcos/
https://www.youtube.com/watch?v=yYnQYF_Xa8g
https://github.com/raspberrypi/pico-examples/tree/master/pio/pwm
https://github.com/raspberrypi/pico-examples/tree/master/pio/pio_blink
https://github.com/raspberrypi/pico-examples/tree/master/pwm/hello_pwm
https://qiita.com/jamjam/items/f2fdd5c072ff348fd809
https://github.com/infovore/pico-example-midi
https://learn.sparkfun.com/tutorials/midi-tutorial/all
http://www.music-software-development.com/midi-tutorial.html
http://midi.teragonaudio.com/tech/midispec/run.htm