ATmega165 datasheet(75/336 Pages) ATMEL

75 / 336 page

ATmega165/V

2573G–AVR–07/09

8-bit Timer/Counter0

with PWM

Timer/Counter0 is a general purpose, single compare unit, 8-bit Timer/Counter module.

The main features are:

• Single Compare Unit 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 (TOV0 and OCF0A)

Overview

A simplified block diagram of the 8-bit Timer/Counter is shown in Figure 27. For the

actual placement of I/O pins, refer to “Pinout ATmega165” 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

page 85.

Figure 27. 8-bit Timer/Counter Block Diagram

Registers

The Timer/Counter (TCNT0) and Output Compare Register (OCR0A) are 8-bit registers.

Interrupt request (abbreviated to Int.Req. in the figure) signals are all visible in the Timer

Interrupt Flag Register (TIFR0). All interrupts are individually masked with the Timer

Interrupt Mask Register (TIMSK0). TIFR0 and TIMSK0 are not shown in the figure.

The Timer/Counter can be clocked internally, via the prescaler, or by an external clock

source on the T0 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

T0).

The double buffered Output Compare Register (OCR0A) is compared with the

Timer/Counter value at all times. The result of the compare can be used by the Wave-

form Generator to generate a PWM or variable frequency output on the Output Compare

pin (OC0A). See “Output Compare Unit” on page 77. for details. The compare match

Timer/Counter

TCNTn

Waveform

Generation

OCn

= 0

Control Logic

= 0xFF

BOTTOM

count

clear

direction

TOVn

(Int.Req.)

OCRn

TCCRn

Clock Select

Edge

Detector

( From Prescaler )

clkTn

TOP

OCn

(Int.Req.)

ATmega165 датащи(PDF) 75 Page - ATMEL Corporation

ATmega165 датащи(HTML) 75 Page - ATMEL Corporation

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

датащи скачать

ссылки URL