This board was modified from the original Pico DCO to act as a secondary DCO board to provide 2 DCO's per voice, as the first DCO board has gate outputs these were not deemed necessary on the second DCO board. This board does not have a MIDI input and takes its MIDI signal from the first board via a buffer, stacking controls are also shared between the 2 boards. Detune and FM inputs are currently seperate, but I think the FM inputs can be linked.
This repository contains source code, schematics 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. Additionally I have removed the gate signals and added 2x 8 channel DACs to provide the 6 CV's and 6 velocity CV's that would normally be available for filter tracking, levels etc. This also makes the board into a 6 note polyphonic MIDI to CV converter. Additionally with the help of Freddie Renyard an FM input is now available. Also an octave select switch allowing a 3 octave adjustment of the DCO's range.
- Digitally controlled analog oscillator using a Raspberry Pi Pico
- Up to six voices
- Voice stacking
- Detuning of voices
- USB MIDI input
- MIDI pitch bend
- Portamento with adjustable speed
- FM input
- V/oct outputs for each note 0-10v
- Velocity CV output 0-5V
- Octave switching
Pico DCO also known as Jan Knipper
https://github.com/polykit/pico-dco
This is how it sounds: Ramp sample Pulse sample Polyphonic sample
Freddie Renyard for his coding of the FM inputs and patience with me whilst I debugged the voice sync of two boards together.
https://github.com/freddie-renyard
Press BOOTSEL button on the Pico while powering it with USB. Copy file build/pico-dco-dac.uf2 onto the USB mass storage device.
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.
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