Datasheet

173
ATmega16U4/32U4 [DATASHEET]
Atmel-7766J-USB-ATmega16U4/32U4-Datasheet_04/2016
• Bits 1:0 - TC49, TC48: Two MSB bits of the 10-bit accesses
If 10-bit accuracy is used, the Timer/Counter4 High Byte Register (TC4H) is used for temporary storing the MSB
bits (TC49, TC48) of the 10-bit accesses. The same TC4H register is shared between all 10-bit registers within
the Timer/Counter4. Note that special procedures must be followed when accessing the 10-bit TCNT4 register
via the 8-bit AVR data bus. These procedures are described in section “Accessing 10-bit Registers” on
page 160.
15.12.8 OCR4A – Timer/Counter4 Output Compare Register A
The output compare register A is an 8-bit read/write register.
The Timer/Counter Output Compare Register A contains data to be continuously compared with
Timer/Counter4. Actions on compare matches are specified in TCCR4A. A compare match does only occur if
Timer/Counter4 counts to the OCR4A value. A software write that sets TCNT4 and OCR4A to the same value
does not generate a compare match.
A compare match will set the compare interrupt flag OCF4A after a synchronization delay following 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 160.
15.12.9 OCR4B – Timer/Counter4 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/Counter4. Actions on compare matches are specified in TCCR4. A compare match does only occur if
Timer/Counter4 counts to the OCR4B value. A software write that sets TCNT4 and OCR4B to the same value
does not generate a compare match.
A compare match will set the compare interrupt flag OCF4B after a synchronization delay following 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 160.
15.12.10OCR4C – Timer/Counter4 Output Compare Register C
The output compare register C is an 8-bit read/write register.
Bit 76543210
MSB LSB OCR4A
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Initial value00000000
Bit 76543210
MSB LSB OCR4B
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Initial value00000000
Bit 76543210
MSB LSB OCR44C
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Initial value11111111