ATMEga64L ATMEL Corporation, ATMEga64L Datasheet - Page 144

• Manufacturer Part Number: ATMEga64L
• Description: 8-bit AVR Microcontroller with 64K Bytes In-System Programmable Flash
• Manufacturer: ATMEL Corporation

8-bit Timer/Counter2
with PWM
Overview
Registers
144
ATmega64(L)
Timer/Counter2 is a general purpose, single-channel, 8-bit Timer/Counter module. The
main features are:
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A simplified block diagram of the 8-bit Timer/Counter is shown in Figure 61. For the
actual placement of I/O pins, refer to “Pin Configuration” on page 2. 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 “8-bit Timer/Counter Register Description” on
page 155.
Figure 61. 8-bit Timer/Counter Block Diagram
The Timer/Counter (TCNT2) and Output Compare Register (OCR2) are 8-bit registers.
Interrupt request (abbreviated to Int.Req. in the figure) signals are all visible in the Timer
Interrupt Flag Register (TIFR). All interrupts are individually masked with the Timer
Interrupt Mask Register (TIMSK). TIFR and TIMSK are not shown in the figure since
these registers are shared by other timer units.
The Timer/Counter can be clocked internally, via the prescaler, or by an external clock
source on the T2 pin. The Clock Select logic block controls which clock source and edge
the Timer/Counter uses to increment (or decrement) its value. The Timer/Counter is
inactive when no clock source is selected. The output from the Clock Select logic is
referred to as the timer clock (clk
Single Channel Counter
Clear Timer on Compare Match (Auto Reload)
Glitch-free, Phase Correct Pulse width Modulator (PWM)
Frequency Generator
External Event Counter
10-bit Clock Prescaler
Overflow and Compare Match Interrupt Sources (TOV2 and OCF2)
Timer/Counter
TCNTn
OCRn
=
direction
count
clear
BOTTOM
= 0
T2
Control Logic
).
=
TCCRn
TOP
0xFF
clk
Tn
Generation
Waveform
Clock Select
( From Prescaler )
Detector
Edge
2490G–AVR–03/04
OCn
(Int.Req.)
TOVn
(Int.Req.)
OCn
Tn