Attached below is basic demo of polyphonic piano using PSoC5 (CY8KIT-059) as processing unit and MIDI Keyboard as input.
This is very basic demo to demonstrate interrupt-driven DDS technique with signal output to 8-bit VDAC. The project is heavily using CPU and interrupts (Arduino-style) and doesn't have any "advanced" features (DMA, etc), but it is good for introduction.
Attached are: project demo, project screenshots, related Cypress application note and YouTube video.
YouTube project demo video: Polyphonic piano demo using PSoC5 and MIDI Keyboard - YouTube
Piano on Arduino (parts 1-4): Arduino MIDI synthesizer (Part 1) - Basic MIDI IN circuit - YouTube
MIDI Keyboard: MIDI Keyboard - Android Apps on Google Play