3.10. AVR timers

The ATmega32U4 has 4 timers: Timer0, Timer1, Timer3, and Timer4. Each timer has a different set of features, as documented in the datasheet.

• Timer0 is used by the Arduino environment for timing-related functions like millis().
• Timer1 is used by the Romi 32U4 Control Board Arduino library for driving motors.
• Timer3 is not used by the Romi 32U4 Arduino library and can be freely used for your own purposes.
• Timer4 is used by the Romi 32U4 Arduino library for controlling the buzzer. The buzzer pin (digital pin 6, or PD7; Timer4 output OC4D) can be freed for other uses by cutting the surface-mount jumper labeled “6 = Buzzer”.