3.12. 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 Zumo 32U4 Arduino library for driving motors.
• Timer3 is used by the Zumo 32U4 Arduino library for emitting 38 kHz IR pulses for the proximity sensors, but it can be used for other purposes between readings of the sensors.
• Timer4 is used by the Zumo 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”.