attiny167-esxz ATMEL Corporation, attiny167-esxz Datasheet - Page 113

• Manufacturer Part Number: attiny167-esxz
• Description: 8-bit Avr 8-bit Microcontroller Microcontroller With 16k Bytes In-system Programmable Flash And Lin Controller
• Manufacturer: ATMEL Corporation

12.7
7728A–AUTO–07/08
Output Compare Units
The 16-bit comparator continuously compares TCNT1 with the Output Compare Register
(OCR1A/B). If TCNT equals OCR1A/B the comparator signals a match. A match will set the
Output Compare Flag (OCF1A/B) at the next timer clock cycle. If enabled (OCIE1A/B = 1), the
Output Compare Flag generates an Output Compare interrupt. The OCF1A/B flag is automati-
cally cleared when the interrupt is executed. Alternatively the OCF1A/B flag can be cleared by
software by writing a logical one to its I/O bit locations. The Waveform Generator uses the match
signal to generate an output according to operating mode set by the Waveform Generation
mode (WGM13:0) bits and Compare Output mode (COM1A/B1:0) bits. The TOP and BOTTOM
signals are used by the Waveform Generator for handling the special cases of the extreme
values in some modes of operation
A special feature of Output Compare unit A allows it to define the Timer/Counter TOP value (i.e.,
counter resolution). In addition to the counter resolution, the TOP value defines the period time
for waveforms generated by the Waveform Generator.
Figure 12-4
diagram that are not directly a part of the Output Compare unit are gray shaded.
Figure 12-4. Output Compare Unit, Block Diagram
The OCR1A/B Register is double buffered when using any of the twelve Pulse Width Modulation
(PWM) modes. For the Normal and Clear Timer on Compare (CTC) modes of operation, the
double buffering is disabled. The double buffering synchronizes the update of the OCR1A/B
Compare Register to either TOP or BOTTOM of the counting sequence. The synchronization
prevents the occurrence of odd-length, non-symmetrical PWM pulses, thereby making the
output glitch-free.
shows a block diagram of the Output Compare unit. The elements of the block
OCRnxH Buf.(8-bit)
OCRnxH (8-bit)
BOTTOM
OCRnx Buffer (16-bit Register)
TEMP (8-bit)
TOP
OCRnx (16-bit Register)
(See Section “12.9” on page
OCRnxL Buf.(8-bit)
OCRnxL (8-bit)
DATA BUS
Waveform Generator
WGMn3:0
=
(16-bit Comparator )
(8-bit)
COMnx1:0
TCNTnH (8-bit)
OCFnx
116.)
TCNTn (16-bit Counter)
(Int.Req.)
TCNTnL (8-bit)
ATtiny167
OCnxW
OCnxX
OCnxU
OCnxV
113