Datasheet

ManualsBrandsMicrochip ManualsAVR MicrocontrollersAVR RISC Microcontroller Flash 32KB TQFP

131

132

133

134

135

136

137

138

139

140

134

ATmega16U4/32U4 [DATASHEET]

Atmel-7766J-USB-ATmega16U4/32U4-Datasheet_04/2016

• 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

Capture Interrupt, if this interrupt is enabled.

When the ICRn is used as TOP value (see description of the WGMn3:0 bits located in the TCCRnA and the

TCCRnB Register), the ICPn is disconnected and consequently the input capture function is disabled.

• Bit 5 – Reserved Bit

This bit is reserved for future use. For ensuring compatibility with future devices, this bit must be written to zero

when TCCRnB is written.

• Bit 4:3 – WGMn3:2: Waveform Generation Mode

See TCCRnA Register description.

• Bit 2:0 – CSn2:0: Clock Select

The three clock select bits select the clock source to be used by the Timer/Counter, see Figure 13-8 on page

102 and Figure 13-9 on page 103.

If external pin modes are used for the Timer/Countern, transitions on the Tn pin will clock the counter even if the

pin is configured as an output. This feature allows software control of the counting.

14.10.5 Timer/Counter1 Control Register C – TCCR1C

Table 14-5. Clock Select Bit Description

CSn2 CSn1 CSn0 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 clk

I/O

/256 (From prescaler)

1 0 1 clk

I/O

/1024 (From prescaler)

1 1 0 External clock source on Tn pin. Clock on falling edge

1 1 1 External clock source on Tn pin. Clock on rising edge

Bit 7654 3 210

FOC1A FOC1B FOC1C – – – – – TCCR1C

Read/WriteWWWR R R R R

Initial Value00000 000