Datasheet

19.11.9 TC3 Control Register B
Name: TCCR3B
Offset: 0x91
Reset: 0x00
Property: -
Bit 7 6 5 4 3 2 1 0
ICNC3 ICES3 WGM3[3] WGM3[2] CS3[2:0]
Access
R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0
Bit 7 – ICNC3 Input Capture Noise Canceler
Writing this bit to '1' activates the Input Capture Noise Canceler. When the noise canceler is activated, the
input from the Input Capture pin (ICP3) is filtered. The filter function requires four successive equal
valued samples of the ICP3 pin for changing its output. The Input Capture is therefore delayed by four
Oscillator cycles when the noise canceler is enabled.
Bit 6 – ICES3 Input Capture Edge Select
This bit selects which edge on the Input Capture pin (ICP3) that is used to trigger a capture event. When
the ICES3 bit is written to zero, a falling (negative) edge is used as a trigger, and when the ICES3 bit is
written to '1', a rising (positive) edge will trigger the capture.
When a capture is triggered according to the ICES3 setting, the counter value is copied into the Input
Capture Register (ICR3). The event will also set the Input Capture Flag (ICF3), and this can be used to
cause an Input Capture Interrupt if this interrupt is enabled.
When the ICR3 is used as TOP value (see description of the WGM13:0 bits located in the TCCR3A and
the TCCR3B Register), the ICP3 is disconnected and consequently, the Input Capture function is
disabled.
Bits 3, 4 – WGM3 Waveform Generation Mode
Refer to TCCR1A.
Bits 2:0 – CS3[2:0] Clock Select 3
The three Clock Select bits select the clock source to be used by the Timer/Counter. Refer to Figure 19-9
and Figure 19-10.
Table 19-12. Clock Select Bit Description
CS32 CS31 CS30 Description
0 0 0 No clock source (Timer/Counter stopped).
0 0 1 clk
I/O
/1 (No prescaling)
0 1 0 clk
I/O
/8 (From prescaler)
0 1 1 clk
I/O
/64 (From prescaler)
1 0 0 clkI/O/256 (From prescaler)
1 0 1 clk
I/O
/1024 (From prescaler)
ATmega328PB
TC1, 3, 4 - 16-bit Timer/Counter1, 3, 4 with PWM
© 2018 Microchip Technology Inc.
Datasheet Complete
DS40001906C-page 191