Atmel ATmega8535L - 8-bit Timer;Counter2 with PWM and Asynchronous Operation; Overview

117
ATmega8535(L)
2502K–AVR–10/06
8-bit Timer/Counter2
with PWM and
Asynchronous
Operation
Timer/Counter2 is a general purpose, single channel, 8-bit Timer/Counter module. The
main features are:
•
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 and OCF2)
• Allows Clocking from External 32 kHz Watch Crystal Independent of the I/O Clock
Overview A simplified block diagram of the 8-bit Timer/Counter is shown in Figure 53. For the
actual placement of I/O pins, refer to “Pinout ATmega8535” 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 128.
Figure 53. 8-bit Timer/Counter Block Diagram
Timer/Counter
DATA BU S
=
TCNTn
Waveform
Generation
OCn
= 0
Control Logic
= 0xFF
TOPBOTTOM
count
clear
direction
TOVn
(Int.Req.)
OCn
(Int.Req.)
Synchronization Unit
OCRn
TCCRn
ASSRn
Status Flags
clk
I/O
clk
ASY
Synchronized Status Flags
Asynchronous Mode
Select (ASn)
TOSC1
T/C
Oscillator
TOSC2
Prescaler
clk
Tn
clk
I/O