ATMEGA644PV ATMEL [ATMEL Corporation], ATMEGA644PV Datasheet - Page 138

• Manufacturer Part Number: ATMEGA644PV
• Description: 8-bit Microcontroller with 16/32/64K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

15. 8-bit Timer/Counter2 with PWM and Asynchronous Operation
15.1
15.2
138
Features
Overview
ATmega164P/324P/644P
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Timer/Counter2 is a general purpose, single channel, 8-bit Timer/Counter module.
A simplified block diagram of the 8-bit Timer/Counter is shown in Figure 14-12.. For the actual
placement of I/O pins, see
ing I/O bits and I/O pins, are shown in bold. The device-specific I/O Register and bit locations
are listed in the
The Power Reduction Timer/Counter2 bit, PRTIM2, in
page 48
Figure 15-1. 8-bit Timer/Counter Block Diagram
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 (TOV2, OCF2A and OCF2B)
Allows Clocking from External 32 kHz Watch Crystal Independent of the I/O Clock
must be written to zero to enable Timer/Counter2 module.
Status flags
”Register Description” on page
Timer/Counter
TCCRnA
TCNTn
OCRnA
OCRnB
=
=
”Pin Configurations” on page
Direction
Count
Clear
ASSRn
Synchronized Status flags
Control Logic
TOP
=
TCCRnB
asynchronous mode
Value
BOTTOM
Fixed
TOP
select (ASn)
clk
=
Tn
0
151.
Prescaler
Synchronization Unit
OCnA
(Int.Req.)
OCnB
(Int.Req.)
2. CPU accessible I/O Registers, includ-
Generation
Generation
Waveform
Waveform
”PRR – Power Reduction Register” on
TOVn
(Int.Req.)
OCnA
OCnB
Oscillator
T/C
clk
I/O
clk
clk
I/O
ASY
8011D–AVR–02/07
TOSC1
TOSC2