An Arduino library to handle the Yamaha digital delay chip, YM7128
Connect the chip's SCI, A0, and Din pins to Arduino pins 5, 6, 7, respectively.
Add a button to pin 2, tied to ground and pulled high when pressed. Then upload.
See the schematic at http://www.dtech.lv/files_ym/ym7128.pdf if you're unsure of how this chip works.
The basic demo include 4 basic patterns.
Uses the Armstrong library (https://github.com/MarquisdeGeek/armstrong) to handle button debounce.