Datasheet

19.11.16 TC4 Control Register B
Name: TCCR4B
Offset: 0xA1
Reset: 0x00
Property: -
Bit 7 6 5 4 3 2 1 0
ICNC4 ICES4 WGM4[3] WGM4[2] CS4[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 – ICNC4 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 (ICP4) is filtered. The filter function requires four successive equal
valued samples of the ICP4 pin for changing its output. The Input Capture is therefore delayed by four
Oscillator cycles when the noise canceler is enabled.
Bit 6 – ICES4 Input Capture Edge Select
This bit selects which edge on the Input Capture pin (ICP4) that is used to trigger a capture event. When
the ICES4 bit is written to zero, a falling (negative) edge is used as a trigger, and when the ICES4 bit is
written to '1', a rising (positive) edge will trigger the capture.
When a capture is triggered according to the ICES4 setting, the counter value is copied into the Input
Capture Register (ICR4). The event will also set the Input Capture Flag (ICF4), and this can be used to
cause an Input Capture Interrupt if this interrupt is enabled.
When the ICR4 is used as TOP value (see description of the WGM4[3:0] bits located in the TCCR4A and
the TCCR4B Register), the ICP4 is disconnected and consequently, the Input Capture function is
disabled.
Bits 3, 4 – WGM4 Waveform Generation Mode
Refer to TCCR4A.
Bits 2:0 – CS4[2:0] Clock Select
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 19-17. Clock Select Bit Description
CS4[2] CS4[1] CS4[0] 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 201