Digital Input to Microcontroller
Most microcontrollers run on either 3.3V or 5V logic, whereas Eurorack gates and triggers are usually between 5-8V....
microcontroller
CV Input to Microcontroller
Many digital modules will need at least one CV input, however you have likely noticed that while Eurorack can have ±12V travelling through its patch cables, most microcontrollers will be very unhappy to receive anything outside of the range 0-3....