ATTINY87-A15XZ Datasheet, PDF (134/283 Pages) ATMEL Corporation – Microcontroller with 8K/16K Bytes In-System Programmable Flash and LIN Controller

• Bit 1:0 – WGM11:0: Waveform Generation Mode
Combined with the WGM13:2 bits found in the TCCR1B Register, these bits control the count-
ing sequence of the counter, the source for maximum (TOP) counter value, and what type of
waveform generation to be used, see Table 12-4. Modes of operation supported by the
Timer/Counter unit are: Normal mode (counter), Clear Timer on Compare match (CTC) mode,
and three types of Pulse Width Modulation (PWM) modes. (See “Modes of Operation” on page
122.).
Table 12-4. Waveform Generation Mode Bit Description ⁽¹⁾
WGM12 WGM11 WGM10
Mode WGM13 (CTC1) (PWM11) (PWM10)
Timer/Counter
Mode of Operation
TOP
Update of
OCR1A/B at
TOV1 Flag
Set on
0
0
0
0
0
Normal
0xFFFF Immediate
MAX
1
0
0
0
1
PWM, Phase Correct, 8-bit 0x00FF
TOP
BOTTOM
2
0
0
1
0
PWM, Phase Correct, 9-bit 0x01FF
TOP
BOTTOM
3
0
0
1
1
PWM, Phase Correct,
10-bit
0x03FF
TOP
BOTTOM
4
0
1
0
0
CTC
OCR1A
Immediate
MAX
5
0
1
0
1
Fast PWM, 8-bit
0x00FF
TOP
TOP
6
0
1
1
0
Fast PWM, 9-bit
0x01FF
TOP
TOP
7
0
1
1
1
Fast PWM, 10-bit
0x03FF
TOP
TOP
8
1
0
0
0
PWM, Phase and
Frequency Correct
ICR1
BOTTOM
BOTTOM
9
1
0
0
1
PWM, Phase and
Frequency Correct
OCR1A
BOTTOM
BOTTOM
10
1
0
1
0
PWM, Phase Correct
ICR1
TOP
BOTTOM
11
1
0
1
1
PWM, Phase Correct
OCR1A
TOP
BOTTOM
12
1
1
0
0
CTC
ICR1
Immediate
MAX
13
1
1
0
1
(Reserved)
–
–
–
14
1
1
1
0
Fast PWM
ICR1
TOP
TOP
15
1
1
1
1
Fast PWM
OCR1A
TOP
TOP
Note: 1. The CTC1 and PWM11:0 bit definition names are obsolete. Use the WGM12:0 definitions. However, the functionality and
location of these bits are compatible with previous versions of the timer.
134 ATtiny87/ATtiny167
7728G–AVR–06/10