AT90PWM2 View Datasheet(PDF) - Atmel Corporation
Part Name
Description
MFG CO.
'AT90PWM2' PDF : 365 Pages View PDF
AT90PWM2/3/2B/3B
Table 15-4. Compare Output Mode, Phase Correct and Phase and Frequency Correct
PWM(1)
COMnA1/COMnB1 COMnA0/COMnB0 Description
WGMn3:0 = 8, 9 10 or 11: Toggle OCnA on Compare
0
1
Match, OCnB disconnected (normal port operation).
For all other WGM1 settings, normal port operation,
OC1A/OC1B disconnected.
Clear OCnA/OCnB on Compare Match when up-
1
0
counting. Set OCnA/OCnB on Compare Match when
downcounting.
Note:
Set OCnA/OCnB on Compare Match when up-
1
1
counting. Clear OCnA/OCnB on Compare Match
when downcounting.
1. A special case occurs when OCRnA/OCRnB equals TOP and COMnA1/COMnB1 is set. See
“Phase Correct PWM Mode” on page 119. for more details.
• Bit 1:0 – WGMn1:0: Waveform Generation Mode
Combined with the WGMn3:2 bits found in the TCCRnB Register, these bits control the counting
sequence of the counter, the source for maximum (TOP) counter value, and what type of wave-
form generation to be used, see Table 15-5. 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 “16-bit Timer/Counter1 with PWM” on page
104.).
Table 15-5. Waveform Generation Mode Bit Description(1)
WGMn2 WGMn1 WGMn0 Timer/Counter Mode of
Mode WGMn3 (CTCn) (PWMn1) (PWMn0) Operation
0
0
0
0
0
Normal
1
0
0
0
1
PWM, Phase Correct, 8-bit
2
0
0
1
0
PWM, Phase Correct, 9-bit
3
0
0
1
1
PWM, Phase Correct, 10-bit
4
0
1
0
0
CTC
5
0
1
0
1
Fast PWM, 8-bit
6
0
1
1
0
Fast PWM, 9-bit
7
0
1
1
1
Fast PWM, 10-bit
8
1
0
0
0
PWM, Phase and Frequency
Correct
9
1
0
0
1
PWM, Phase and Frequency
Correct
10
1
0
1
0
PWM, Phase Correct
11
1
0
1
1
PWM, Phase Correct
12
1
1
0
0
CTC
13
1
1
0
1
(Reserved)
14
1
1
1
0
Fast PWM
15
1
1
1
1
Fast PWM
TOP
0xFFFF
0x00FF
0x01FF
0x03FF
OCRnA
0x00FF
0x01FF
0x03FF
ICRn
OCRnA
ICRn
OCRnA
ICRn
–
ICRn
OCRnA
Update of
OCRnx at
Immediate
TOP
TOP
TOP
Immediate
TOP
TOP
TOP
TOVn Flag
Set on
MAX
BOTTOM
BOTTOM
BOTTOM
MAX
TOP
TOP
TOP
BOTTOM BOTTOM
BOTTOM BOTTOM
TOP
TOP
Immediate
–
TOP
TOP
BOTTOM
BOTTOM
MAX
–
TOP
TOP
4317K–AVR–03/2013
126
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