119
ATmega16M1/32M1/64M1 [DATASHEET]
8209E–AVR–11/2012
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.
15.11.2
TCCR1B – Timer/Counter1 Control Register B
Bit 7 – ICNCn: Input Capture Noise Canceler
Setting this bit (to one) activates the Input Capture Noise Canceler. When the noise canceler 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.
Bit 6 – ICESn: Input Capture Edge Select
This bit selects which edge on the Input Capture pin (ICPn) that is used to trigger a capture event. When the ICESn
bit is written to zero, a falling (negative) edge is used as trigger, and when the ICESn bit is written to one, a rising
(positive) edge will trigger the capture.
When a capture is triggered according to the ICESn setting, the counter value is copied into the Input Capture Reg-
ister (ICRn). The event will also set the Input Capture Flag (ICFn), and this can be used to cause an Input Capture
Interrupt, if this interrupt is enabled.
Table 15-5.
Waveform Generating 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
Normal
0xFFFF
Immediate
MAX
1
0
1
PWM, phase correct, 8-bit
0x00FF
TOP
BOTTOM
2
0
1
0
PWM, phase correct, 9-bit
0x01FF
TOP
BOTTOM
3
0
1
PWM, phase correct, 10-bit
0x03FF
TOP
BOTTOM
4
0
1
0
CTC
OCRnA
Immediate
MAX
5
0
1
0
1
Fast PWM, 8-bit
0x00FF
TOP
6
0
1
0
Fast PWM, 9-bit
0x01FF
TOP
7
0
1
Fast PWM, 10-bit
0x03FF
TOP
8
100
0
PWM, phase and frequency
correct
ICRn
BOTTOM
9
100
1
PWM, phase and frequency
correct
OCRnA
BOTTOM
10
1
0
1
0
PWM, phase correct
ICRn
TOP
BOTTOM
11
1
0
1
PWM, phase correct
OCRnA
TOP
BOTTOM
12
1
0
CTC
ICRn
Immediate
MAX
13
1
0
1
(Reserved)
–
14
1
0
Fast PWM
ICRn
TOP
15
1
Fast PWM
OCRnA
TOP
Bit
7
65
4
3
210
ICNC1
ICES1
RTGEN
WGM13
WGM12
CS12
CS11
CS10
TCCR1B
Read/write
R/W
R
R/W
Initial value
0