ATmega16HVB datasheet(88/273 Pages) ATMEL

88 / 273 page

8042A–AVR–07/09

ATmega16HVB/32HVB

cleared by software (writing a logical one to the I/O bit location). For measuring frequency only,

the trigger edge change is not required.

Note:

1. See ”OSI – Oscillator Sampling Interface” on page 29 for details.

2. The noise canceler cannot be used with this source.

Note:

1. The noise canceller will filter out the input capture and it is therefore not recommended to use

noise canceler with these sources.

17.7

Output Compare Unit

The comparator continuously compares the Timer/Counter (TCNTn) with the Output Compare

Registers (OCRnA and OCRnB), and whenever the Timer/Counter equals to the Output Com-

pare Registers, the comparator signals a match. A match will set the Output Compare Flag at

the next timer clock cycle. In 8-bit mode the match can set either the Output Compare Flag

OCFnA or OCFnB, but in 16-bit mode the match can set only the Output Compare Flag OCFnA

as there is only one Output Compare Unit. If the corresponding interrupt is enabled, the Output

Compare Flag generates an Output Compare interrupt. The Output Compare Flag is automati-

cally cleared when the interrupt is executed. Alternatively, the flag can be cleared by software by

writing a logical one to its I/O bit location. Figure 17-5 on page 88 shows a block diagram of the

Output Compare unit.

Figure 17-5. Output Compare Unit, Block Diagram

Table 17-3.

Timer/Counter0 Input Capture Source (ICS)

ICS0

Source

ICP00: Port PB0

ICP01: osi_posedge pin from OSI module(1)(2)

Table 17-4.

Timer/Counter1 Input Capture Source (ICS)

ICS1

Source

ICP10: Battery Protection Interrupt(1)

ICP11: Voltage Regulator Interrupt(1)

OCFnx (Int.Req.)

= (8/16-bit Comparator )

OCRnx

DATA BUS

TCNTn

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