SAM3S8B Atmel Corporation, SAM3S8B Datasheet - Page 880

• Manufacturer Part Number: SAM3S8B
• Manufacturer: Atmel Corporation

880
880
SAM3S8/SD8
SAM3S8/SD8
Figure 35-4. Non Overlapped Center Aligned Waveforms
Note:
When center aligned, the channel counter increases up to CPRD and decreases down to 0. This
ends the period.
When left aligned, the channel counter increases up to CPRD and is reset. This ends the period.
Thus, for the same CPRD value, the period for a center aligned channel is twice the period for a
left aligned channel.
Waveforms are fixed at 0 when:
Waveforms are fixed at 1 (once the channel is enabled) when:
The waveform polarity must be set before enabling the channel. This immediately affects the
channel output level. Changes on channel polarity are not taken into account while the channel
is enabled.
Besides generating output signals OCx, the comparator generates interrupts in function of the
counter value. When the output waveform is left aligned, the interrupt occurs at the end of the
counter period. When the output waveform is center aligned, the bit CES of the PWM_CMRx
register defines when the channel counter interrupt occurs. If CES is set to 0, the interrupt
occurs at the end of the counter period. If CES is set to 1, the interrupt occurs at the end of the
counter period and at half of the counter period.
Figure 35-5 “Waveform Properties”
configuration.
• 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
• CDTY = CPRD and CPOL = 0
• CDTY = 0 and CPOL = 1
• CDTY = 0 and CPOL = 0
• CDTY = CPRD and CPOL = 1
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.
OC0
OC1
1. See
Figure 35-5 on page 881
No overlap
Period
for a detailed description of center aligned waveforms.
illustrates the counter interrupts in function of the
11090A–ATARM–10-Feb-12
11090A–ATARM–10-Feb-12