Datasheet

ManualsBrandsMICROCHIP TECHNOLOGY ManualsMicrocontrollers, Microprocessors & QuartzesEmbedded microcontroller VFQFN 28 (4x4) 8-Bit 20 MHz I/O number 23

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20.15.2 TC1 Control Register B

Name: TCCR1B

Offset: 0x81

Reset: 0x00

Property: -

Bit 7 6 5 4 3 2 1 0

ICNC1 ICES1 WGM13 WGM12 CS1[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 – ICNC1 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 (ICP1) is filtered. The filter function requires four successive equal

valued samples of the ICP1 pin for changing its output. The input capture is therefore delayed by four

oscillator cycles when the noise canceler is enabled.

Bit 6 – ICES1 Input Capture Edge Select

This bit selects which edge on the Input Capture pin (ICP1) that is used to trigger a capture event. When

the ICES1 bit is written to zero, a falling (negative) edge is used as a trigger, and when the ICES1 bit is

written to '1', a rising (positive) edge will trigger the capture.

When a capture is triggered according to the ICES1 setting, the counter value is copied into the Input

Capture Register (ICR1). The event will also set the Input Capture Flag (ICF1) and this can be used to

cause an input capture interrupt, if this interrupt is enabled.

When the ICR1 is used as TOP value (see description of the WGM1[3:0] bits located in the TCCR1A and

the TCCR1B register), the ICP1 is disconnected and consequently, the input capture function is disabled.

Bits 3, 4 – WGM1 Waveform Generation Mode

Refer to 20.15.1 TCCR1A.

Bits 2:0 – CS1[2:0] Clock Select 1

The three clock select bits select the clock source to be used by the timer/counter. Refer to Figure 20-10

and Figure 20-11.

Table 20-7. Clock Select Bit Description

CS1[2] CS1[1] CS1[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)

ATmega48PA/88PA/168PA

16-bit Timer/Counter1 (TC1) with PWM

Datasheet Complete

DS40002011A-page 186