samd21_mini_synth

Lo-Fi SAMD21 based mini chip tune synthesizer
Seeed Studio - Seeeduino XIAO arduino project

link to the video

Description

This time I went back to a very small controller: ATSAMD21G18A on a [Seeeduino XIAO aka Seeed Studio XIAO SAMD21](https://www.seeedstudio.com/Seeeduino-XIAO-Arduino-Microcontroller-SAMD21-Cortex-M0+-p-4426.html) The chip tune like polyphonic synthesizer is the result of my little experiment It runs with "only" 48MHz without FPU and has one DAC (real analog output with 10 bit resolution)

Tested with arduino board 'seeed_XIAO_m0'

Some key features:

• 24 voices polyphony (more might be possible) / set to 12 for better performance
• Different selectable waveforms (sine, saw, square, pulse, tri)
• Separate setting per MIDI channel
• Short delay effect (250ms) with feedback control
• Pitchbend and modulation
• Modulation lfo waveforms: (sine, saw, square, pulse, tri, prn)
• Controllable intensity and speed of lfo

Connections

- RX pin for MIDI in (please use a dedicated circuit with an opto-coupler) - DAC as audio out (requires a capacitor in series and an amplifier)

Options

Please activate KEYB_USB_HOST_ENABLED in config.h to allow connecting an USB keyboard. - the keyboard can be connected using an OTG USB adapter - in addition to that you might need an external 5v power supply