ATmega16U4 datasheet(139/408 Pages) ATMEL

139 / 408 page

139

7766D–AVR–01/09

ATmega16U4/ATmega32U4

15. 10-bit High Speed Timer/Counter4

15.1

Features

• Up to 10-Bit Accuracy

• Three Independent Output Compare Units

• Clear Timer on Compare Match (Auto Reload)

• Glitch Free, Phase and Frequency Correct Pulse Width Modulator (PWM)

• Enhanced PWM mode: one optional additional accuracy bit without effect on output frequency

• Variable PWM Period

• Independent Dead Time Generators for each PWM channels

• Synchronous update of PWM registers

• Five Independent Interrupt Sources (TOV4, OCF4A, OCF4B, OCF4D, FPF4)

• High Speed Asynchronous and Synchronous Clocking Modes

• Separate Prescaler Unit

15.2

Overview

Timer/Counter4 is a general purpose high speed Timer/Counter module, with three independent

Output Compare Units, and with enhanced PWM support.

The Timer/Counter4 features a high resolution and a high accuracy usage with the lower pres-

caling opportunities. It can also support three accurate and high speed Pulse Width Modulators

using clock speeds up to 64 MHz. In PWM mode Timer/Counter4 and the output compare regis-

ters serve as triple stand-alone PWMs with non-overlapping, non-inverted and inverted outputs.

The enhanced PWM mode allows to get one more accuracy bit while keeping the frequency

identical to normal mode (a PWM 8 bits accuracy in enhanced mode outputs the same fre-

quency that a PWM 7 bits accuracy in normal mode). Similarly, the high prescaling opportunities

make this unit useful for lower speed functions or exact timing functions with infrequent actions.

A lock feature allows user to update the PWM registers and

A simplified block diagram of the Timer/Counter4 is shown in Figure 15-1. For actual placement

of the I/O pins, refer to “Pinout ATmega16U4/ATmega32U4” on page 3. The device-specific I/O

ATmega16U4 Datasheet(PDF) 139 Page - ATMEL Corporation