Datasheet

20. 16-bit Timer/Counter (Timer/Counter1 and Timer/Counter3)
20.1. Features
• True 16-bit Design (i.e., allows 16-bit PWM)
• Three independent Output Compare Units
• Double Buffered Output Compare Registers
• One Input Capture Unit
• Input Capture Noise Canceler
• Clear Timer on Compare Match (Auto Reload)
• Glitch-free, Phase Correct Pulse Width Modulator (PWM)
• Variable PWM Period
• Frequency Generator
• External Event Counter
• Ten Independent Interrupt Sources (TOV1, OCF1A, OCF1B, OCF1C, ICF1, TOV3, OCF3A,
OCF3B, OCF3C, and ICF3)
20.1.1. Restrictions in ATmega103 Compatibility Mode
Note that in ATmega103 compatibility mode, only one 16-bit Timer/Counter is available (Timer/Counter1).
Also note that in ATmega103 compatibility mode, the Timer/Counter1 has two Compare Registers
(Compare A and Compare B) only.
20.2. Overview
The 16-bit Timer/Counter unit allows accurate program execution timing (event management), wave
generation, and signal timing measurement. Most register and bit references in this document are written
in general form. A lower case “n” replaces the Timer/Counter number, and a lower case “x” replaces the
Output Compare unit channel. However, when using the register or bit defines in a program, the precise
form must be used i.e., TCNT1 for accessing Timer/Counter1 counter value and so on.
A simplified block diagram of the 16-bit Timer/Counter is shown below. For the actual placement of I/O
pins, refer to Pin Configurations. CPU accessible I/O Registers, including I/O bits and I/O pins, are shown
in bold. The device-specific I/O Register and bit locations are listed in the Register Description on page
157.
Atmel ATmega64A [DATASHEET]
Atmel-8160E-ATmega64A_Datasheet_Complete-09/2015
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