Datasheet

21. 8-bit Timer/Counter0 with PWM and Asynchronous Operation
21.1. Features
• Single Channel Counter
• Clear Timer on Compare Match (Auto Reload)
• Glitch-free, phase Correct Pulse Width Modulator (PWM)
• Frequency Generator
• 10-bit Clock Prescaler
• Overflow and Compare Match Interrupt Sources (TOV0 and OCF0)
• Allows Clocking from External 32kHz Watch Crystal Independent of the I/O Clock
21.2. Overview
Timer/Counter0 is a general purpose, single channel, 8-bit Timer/Counter module. A simplified block
diagram of the 8-bit Timer/Counter is shown in the figure 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 205.
Figure 21-1 8-bit Timer/Counter Block Diagram
Timer/Counte r
DATA BUS
=
TCNTn
Waveform
Gene ra tion
OCn
= 0
Control Logic
= 0xFF
TOPBOTTOM
count
clea r
direction
TOVn
(Int. Req.)
OCn
(Int. Req.)
Synchro nization Unit
OCRn
TCCRn
ASS Rn
Sta tus Flags
clk
I/O
clk
ASY
Synchronize d Sta tus Fla gs
as ynchronous Mode
Se le ct (ASn)
TOSC1
T/C
Oscillator
TOSC2
Pre sca ler
clk
Tn
clk
I/O
Related Links
Pin Configurations on page 14
Atmel ATmega64A [DATASHEET]
Atmel-8160E-ATmega64A_Datasheet_Complete-09/2015
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