Atmel ARM-Based Evaluation Kit for SAM4S16C, 32-Bit ARM® Cortex® Microcontroller ATSAM4S-WPIR-RD ATSAM4S-WPIR-RD Data Sheet

SAM4S Series [DATASHEET]

Atmel-11100G-ATARM-SAM4S-Datasheet_27-May-14

950



If the channel is an asynchronous channel (SYNCx = 0 in 

(PWM_SCM)), these registers hold the new period, duty-cycle and dead-times values until the end of the 

current PWM period and update the values for the next period.



If the channel is a synchronous channel and update method 0 is selected (SYNCx = 1 and UPDM = 0 in 

PWM_SCM register), these registers hold the new period, duty-cycle and dead-times values until the bit 

UPDULOCK is written at ‘1’ (in 

 (PWM_SCUC)) and the end 

of the current PWM period, then update the values for the next period.



If the channel is a synchronous channel and update method 1 or 2 is selected (SYNCx = 1 and UPDM = 1 or 

2 in PWM_SCM register):

̶

registers PWM_CPRDUPDx and PWM_DTUPDx hold the new period and dead-times values until the 

bit UPDULOCK is written at ‘1’ (in PWM_SCUC) and the end of the current PWM period, then update 

the values for the next period. 

̶

register PWM_CDTYUPDx holds the new duty-cycle value until the end of the update period of 

synchronous channels (when UPRCNT is equal to UPR in 

 (PWM_SCUP)) and the end of the current PWM period, then updates the value for the next 

period.

Note:

If the update registers PWM_CDTYUPDx, PWM_CPRDUPDx and PWM_DTUPDx are written several times between 

two updates, only the last written value is taken into account.

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 943 and “Method 3: Automatic 

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