at91sam9263 ATMEL Corporation, at91sam9263 Datasheet - Page 717

• Manufacturer Part Number: at91sam9263
• Description: At91 Arm Thumb Microcontrollers
• Manufacturer: ATMEL Corporation

Figure 38-4. Non Overlapped Center Aligned Waveforms
6249D–ATARM–20-Dec-07
PWM0
PWM1
Note:
When center aligned, the internal channel counter increases up to CPRD and.decreases down
to 0. This ends the period.
• the waveform duty cycle. This channel parameter is defined in the CDTY field of the
• the waveform polarity. At the beginning of the period, the signal can be at high or low level.
• the waveform alignment. The output waveform can be left or center aligned. Center aligned
If the waveform is center aligned then the output waveform period depends on the counter
source clock and can be calculated:
By using the Master Clock (MCK) divided by an X given prescaler value
(with X being 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, or 1024). The resulting period formula will
be:
By using a Master Clock divided by one of both DIVA or DIVB divider, the formula becomes,
respectively:
PWM_CDTYx register.
If the waveform is left aligned then:
If the waveform is center aligned, then:
This property is defined in the CPOL field of the PWM_CMRx register. By default the signal
starts by a low level.
waveforms can be used to generate non overlapped waveforms. This property is defined in
the CALG field of the PWM_CMRx register. The default mode is left aligned.
No overlap
(
---------------------------------------- -
(
--------------------------------------------------- -
(
----------------------------------------- -
2
2
CRPD DIVA
duty cycle
×
×
duty cycle
X CPRD
CPRD DIVA
1. See
MCK
MCK
×
MCK
×
Period
×
Figure 38-5 on page 719
=
)
)
=
(
------------------------------------------------------------------------------------------------------- -
or
period 1 fchannel_x_clock
(
---------------------------------------------------------------------------------------------------------------------- -
)
(
period 2 ⁄
or
(
--------------------------------------------- -
CRPD DIVAB
(
--------------------------------------------------- -
2 CPRD
–
×
MCK
×
⁄
) 1 fchannel_x_clock
MCK
–
×
period
⁄
(
DIVB
)
period 2 ⁄
for a detailed description of center aligned waveforms.
)
AT91SAM9263 Preliminary
)
×
CDTY
×
CDTY
)
) )
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