930
11100B–ATARM–31-Jul-12
SAM4S Series [Preliminary]
Figure 37-17. Synchronized Period, Duty-Cycle and Dead-Times Update
37.6.5.4
Changing the Synchronous Channels Update Period
It is possible to change the update period of synchronous channels while they are enabled. (See
“Method 2: Manual write of duty-cycle values and automatic trigger of the update” on page 921
and
“Method 3: Automatic write of duty-cycle values and automatic trigger of the update” on
.)
To prevent an unexpected update of the synchronous channels registers, the user must use the
“PWM Sync Channels Update Period Update Register”
(PWM_SCUPUPD) to change the
update period of synchronous channels while they are still enabled. This register holds the new
value until the end of the update period of synchronous channels (when UPRCNT is equal to
UPR in
“PWM Sync Channels Update Period Register”
(PWM_SCUP)) and the end of the cur-
rent PWM period, then updates the value for the next period.
Note:
If the update register PWM_SCUPUPD is written several times between two updates, only the last
written value is taken into account.
Note:
Changing the update period does make sense only if there is one or more synchronous channels
and if the update method 1 or 2 is selected (UPDM = 1 or 2 in
“PWM Sync Channels Mode Regis-
).
PWM_CPRDUPDx Value
PWM_CPRDx
PWM_CDTYx
- If Asynchronous Channel
-> End of PWM period
- If Synchronous Channel
-> End of PWM period and UPDULOCK = 1
User's Writing
PWM_DTUPDx Value
User's Writing
PWM_DTx
- If Asynchronous Channel
-> End of PWM period
- If Synchronous Channel
- If UPDM = 0
-> End of PWM period and UPDULOCK = 1
- If UPDM = 1 or 2
-> End of PWM period and end of Update Period
PWM_CDTYUPDx Value
User's Writing
Summary of Contents for SAM4S Series
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