Datasheet

97
ATmega8(L)
2486M–AVR–12/03
what type of waveform generation to be used, see Table 39. 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 86.)
Note: 1. The CTC1 and PWM11:0 bit definition names are obsolete. Use the WGM12:0 definitions. However, the functionality and
location of these bits are compatible with previous versions of the timer.
Table 39. Waveform Generation Mode Bit Description
Mode WGM13
WGM12
(CTC1)
WGM11
(PWM11)
WGM10
(PWM10)
Timer/Counter Mode of
Operation
(1)
TOP
Update of
OCR1x
TOV1 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 OCR1A 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
ICR1 BOTTOM BOTTOM
9 1 0 0 1 PWM, Phase and Frequency
Correct
OCR1A BOTTOM BOTTOM
10 1 0 1 0 PWM, Phase Correct ICR1 TOP BOTTOM
11 1 0 1 1 PWM, Phase Correct OCR1A TOP BOTTOM
12 1 1 0 0 CTC ICR1 Immediate MAX
13 1 1 0 1 (Reserved) – – –
14 1 1 1 0 Fast PWM ICR1 TOP TOP
15 1 1 1 1 Fast PWM OCR1A TOP TOP