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Atmega162/v – Rainbow Electronics ATmega162V User Manual

Page 129

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129

ATmega162/V

2513E–AVR–09/03

• Bit 1:0 – WGMn1:0: Waveform Generation Mode

Combined with the WGMn3:2 bits found in the TCCRnB Register, these bits control the
counting sequence of the counter, the source for maximum (TOP) counter value, and
what type of waveform generation to be used, see Table 56. Modes of operation sup-
ported by the Timer/Counter unit are: Normal mode (counter), Clear Timer on Compare
match (CTC) mode, and three types of Pulse Width Modulation (PWM) modes. (See
“Modes of Operation” on page 117.
)

Note:

1. The CTCn and PWMn1:0 bit definition names are obsolete. Use the WGMn2:0 definitions. However, the functionality and

location of these bits are compatible with previous versions of the timer.

Table 56. Waveform Generation Mode Bit Description

(1)

Mode

WGMn3

WGMn2

(CTCn)

WGMn1

(PWMn1)

WGMn0

(PWMn0)

Timer/Counter Mode of Operation

TOP

Update of
OCRn

x

at

TOVn Flag
Set on

0

0

0

0

0

Normal

0xFFFF

Immediate

MAX

1

0

0

0

1

PWM, Phase Correct, 8-bit

0x00FF

TOP

BOTTOM

2

0

0

1

0

PWM, Phase Correct, 9-bit

0x01FF

TOP

BOTTOM

3

0

0

1

1

PWM, Phase Correct, 10-bit

0x03FF

TOP

BOTTOM

4

0

1

0

0

CTC

OCRnA

Immediate

MAX

5

0

1

0

1

Fast PWM, 8-bit

0x00FF

TOP

TOP

6

0

1

1

0

Fast PWM, 9-bit

0x01FF

TOP

TOP

7

0

1

1

1

Fast PWM, 10-bit

0x03FF

TOP

TOP

8

1

0

0

0

PWM, Phase and Frequency Correct

ICRn

BOTTOM

BOTTOM

9

1

0

0

1

PWM, Phase and Frequency Correct

OCRnA

BOTTOM

BOTTOM

10

1

0

1

0

PWM, Phase Correct

ICRn

TOP

BOTTOM

11

1

0

1

1

PWM, Phase Correct

OCRnA

TOP

BOTTOM

12

1

1

0

0

CTC

ICRn

Immediate

MAX

13

1

1

0

1

Reserved

14

1

1

1

0

Fast PWM

ICRn

TOP

TOP

15

1

1

1

1

Fast PWM

OCRnA

TOP

TOP