Timer/counter 1 control register b – tccr1b, Timer/counter 3 control register b – tccr3b, Table 61 – Rainbow Electronics ATmega128L User Manual
Page 130: Atmega128(l)
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130
ATmega128(L)
2467B–09/01
Note:
1. The CTCn and PWMn1:0 bit definition names are obsolete. Use the
WGM
n2:0 definitions. However, the functionality and
location of these bits are compatible with previous versions of the timer.
Timer/Counter 1 Control
Register B – TCCR1B
Timer/Counter 3 Control
Register B – TCCR3B
• Bit 7 - ICNCn: Input Capture Noise Canceler
Setting this bit (to one) activates the input capture noise canceler. When the noise can-
celer is activated, the input from the Input Capture Pin (ICPn) is filtered. The filter
function requires four successive equal valued samples of the ICPn pin for changing its
output. The input capture is therefore delayed by four oscillator cycles when the noise
canceler is enabled.
Table 61. Waveform Generation Mode Bit Description
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
Bit
7
6
5
4
3
2
1
0
ICNC1
ICES1
–
WGM13
WGM12
CS12
CS11
CS10
TCCR1B
Read/Write
R/W
R/W
R
R/W
R/W
R/W
R/W
R/W
Initial value
0
0
0
0
0
0
0
0
Bit
7
6
5
4
3
2
1
0
ICNC3
ICES3
–
WGM33
WGM32
CS32
CS31
CS30
TCCR3B
Read/Write
R/W
R/W
R
R/W
R/W
R/W
R/W
R/W
Initial value
0
0
0
0
0
0
0
0