Data Sheet

136
ATmega48A/PA/88A/PA/168A/PA/328/P [DATASHEET]
Atmel-8271H-AVR- ATmega-Datasheet_08/2014
16.11.5 OCR1AH and OCR1AL – Output Compare Register 1 A
16.11.6 OCR1BH and OCR1BL – Output Compare Register 1 B
The Output Compare Registers contain a 16-bit value that is continuously compared with the counter value
(TCNT1). A match can be used to generate an Output Compare interrupt, or to generate a waveform output on
the OC1x pin.
The Output Compare Registers are 16-bit in size. To ensure that both the high and low bytes are written
simultaneously when the CPU writes to these registers, the access is performed using an 8-bit temporary High
Byte Register (TEMP). This temporary register is shared by all the other 16-bit registers. See ”Accessing 16-bit
Registers” on page 114.
16.11.7 ICR1H and ICR1L – Input Capture Register 1
The Input Capture is updated with the counter (TCNT1) value each time an event occurs on the ICP1 pin (or
optionally on the Analog Comparator output for Timer/Counter1). The Input Capture can be used for defining the
counter TOP value.
The Input Capture Register is 16-bit in size. To ensure that both the high and low bytes are read simultaneously
when the CPU accesses these registers, the access is performed using an 8-bit temporary High Byte Register
(TEMP). This temporary register is shared by all the other 16-bit registers. See ”Accessing 16-bit Registers” on
page 114.
16.11.8 TIMSK1 – Timer/Counter1 Interrupt Mask Register
• Bit 7, 6 – Reserved
These bits are unused bits in the ATmega48A/PA/88A/PA/168A/PA/328/P, and will always read as zero.
• Bit 5 – ICIE1: Timer/Counter1, Input Capture Interrupt Enable
When this bit is written to one, and the I-flag in the Status Register is set (interrupts globally enabled), the
Timer/Counter1 Input Capture interrupt is enabled. The corresponding Interrupt Vector (see “Interrupts” on page
58) is executed when the ICF1 Flag, located in TIFR1, is set.
Bit 76543210
(0x89) OCR1A[15:8] OCR1AH
(0x88) OCR1A[7:0] OCR1AL
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 76543210
(0x8B) OCR1B[15:8] OCR1BH
(0x8A) OCR1B[7:0] OCR1BL
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 76543210
(0x87) ICR1[15:8] ICR1H
(0x86) ICR1[7:0] ICR1L
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 76543210
(0x6F) – – ICIE1 – – OCIE1B OCIE1A TOIE1 TIMSK1
Read/Write R R R/W R R R/W R/W R/W
Initial Value00000000