Atmel Evaluation Kit AT91SAM9X25-EK AT91SAM9X25-EK データシート

729

SAM9X25 [DATASHEET]

11054E–ATARM–10-Mar-2014

To prevent overwriting the PWM_CUPDx by software, the user can use status events in order to synchronize his 
software. Two methods are possible. In both, the user must enable the dedicated interrupt in PWM_IER at PWM 
Controller level. 

The first method (polling method) consists of reading the relevant status bit in PWM_ISR Register according to the 
enabled channel(s). See 

The second method uses an Interrupt Service Routine associated with the PWM channel. 
Note:

Reading the PWM_ISR register automatically clears CHIDx flags.

Note:

Polarity and alignment can be modified only when the channel is disabled. 

Depending on the interrupt mask in the PWM_IMR register, an interrupt is generated at the end of the corresponding 
channel period. The interrupt remains active until a read operation in the PWM_ISR register occurs.

PWM_CUPDx Value

PWM_CPRDx

PWM_CDTYx

End of Cycle

PWM_CMRx. CPD

User's Writing

1

0

Writing in PWM_CUPDx

The last write has been taken into account

CHIDx = 1

Writing in CPD field

Update of the Period or Duty Cycle

PWM_ISR Read

Acknowledgement and clear previous register state

YES