9 ocr1b - timer/counter1 output compare register b – Rainbow Electronics ATtiny861_V User Manual

Page 122

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122

2588B–AVR–11/06

ATtiny261/461/861

The Timer/Counter Output Compare Register A contains data to be continuously compared with
Timer/Counter1. Actions on compare matches are specified in TCCR1A. A compare match does
only occur if Timer/Counter1 counts to the OCR1A value. A software write that sets TCNT1 and
OCR1A to the same value does not generate a compare match.

A compare match will set the compare interrupt flag OCF1A after a synchronization delay follow-
ing the compare event.

Note that, if 10-bit accuracy is used special procedures must be followed when accessing the
internal 10-bit Ouput Compare Registers via the 8-bit AVR data bus. These procedures are
described in section

”Accessing 10-Bit Registers” on page 110

.

16.11.9

OCR1B – Timer/Counter1 Output Compare Register B

The output compare register B is an 8-bit read/write register.

The Timer/Counter Output Compare Register B contains data to be continuously compared with
Timer/Counter1. Actions on compare matches are specified in TCCR1. A compare match does
only occur if Timer/Counter1 counts to the OCR1B value. A software write that sets TCNT1 and
OCR1B to the same value does not generate a compare match.

A compare match will set the compare interrupt flag OCF1B after a synchronization delay follow-
ing the compare event.

Note that, if 10-bit accuracy is used special procedures must be followed when accessing the
internal 10-bit Output Compare Registers via the 8-bit AVR data bus. These procedures are
described in section

”Accessing 10-Bit Registers” on page 110

.

16.11.10 OCR1C – Timer/Counter1 Output Compare Register C

The output compare register C is an 8-bit read/write register.

The Timer/Counter Output Compare Register C contains data to be continuously compared with
Timer/Counter1, and a compare match will clear TCNT1. This register has the same function in
Normal mode and PWM modes.

Note that, if a smaller value than three is written to the Output Compare Register C, the value is
automatically replaced by three as it is a minumum value allowed to be written to this register.

Note that, if 10-bit accuracy is used special procedures must be followed when accessing the
internal 10-bit Output Compare Registers via the 8-bit AVR data bus. These procedures are
described in section

”Accessing 10-Bit Registers” on page 110

.

Bit

7

6

5

4

3

2

1

0

0x2C (0x4C)

MSB

LSB

OCR1B

Read/Write

R/W

R/W

R/W

R/W

R/W

R/W

R/W

R/W

Initial value

0

0

0

0

0

0

0

0

Bit

7

6

5

4

3

2

1

0

0x2B (0x4B)

MSB

LSB

OCR1C

Read/Write

R/W

R/W

R/W

R/W

R/W

R/W

R/W

R/W

Initial value

1

1

1

1

1

1

1

1

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