SAM3SD8C Atmel Corporation, SAM3SD8C Datasheet - Page 895

• Manufacturer Part Number: SAM3SD8C
• Manufacturer: Atmel Corporation

35.6.3
11090A–ATARM–10-Feb-12
11090A–ATARM–10-Feb-12
PWM Comparison Units
The PWM provides 8 independent comparison units able to compare a programmed value with
the current value of the channel 0 counter (which is the channel counter of all synchronous
channels,
erate pulses on the event lines (used to synchronize ADC, see
Lines”), to generate software interrupts and to trigger PDC transfer requests for the synchronous
channels (see
update” on page
Figure 35-14. Comparison Unit Block Diagram
The comparison x matches when it is enabled by the bit CEN in the
Register”
the comparison value defined by the field CV in
(PWM_CMPVx for the comparison x). If the counter of the channel 0 is center aligned (CALG =
1 in
is made when the counter is counting up or counting down (in left alignment mode CALG=0, this
bit is useless).
If a fault is active on the channel 0, the comparison is disabled and cannot match (see
35.6.2.6 “Fault
The user can define the periodicity of the comparison x by the fields CTR and CPR (in
PWM_CMPVx). The comparison is performed periodically once every CPR+1 periods of the
counter of the channel 0, when the value of the comparison period counter CPRCNT (in
PWM_CMPMx) reaches the value defined by CTR. CPR is the maximum value of the compari-
son period counter CPRCNT. If CPR=CTR=0, the comparison is performed at each period of the
counter of the channel 0.
The comparison x configuration can be modified while the channel 0 is enabled by using the
“PWM Comparison x Mode Update Register”
x). In the same way, the comparison x value can be modified while the channel 0 is enabled by
using the
comparison x).
“PWM Channel Mode Register”
“PWM Comparison x Value Update Register”
Section 35.6.2.7 “Synchronous
(PWM_CMPMx for the comparison x) and when the counter of the channel 0 reaches
Protection”).
CEN [PWM_CMPM]x
fault on channel 0
CV [PWM_CMPVx]
CNT [PWM_CCNT0]
CNT [PWM_CCNT0] is decrementing
CVM [PWM_CMPVx]
CALG [PWM_CMR0]
CPRCNT [PWM_CMPMx]
CTR [PWM_CMPMx]
“Method 3: Automatic write of duty-cycle values and automatic trigger of the
892).
), the bit CVM (in PWM_CMPVx) defines if the comparison
Channels”). These comparisons are intended to gen-
=
=
=
(PWM_CMPMUPDx registers for the comparison
1
0
1
“PWM Comparison x Value Register”
(PWM_CMPVUPDx registers for the
Section 35.6.4 “PWM Event
“PWM Comparison x Mode
SAM3S8/SD8
SAM3S8/SD8
Comparison x
Section
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