52832 PPI for timer and PWM

[K-night]

hi, 

I want to use PPI function for timer trigger to PWM, but I noticed PWM doesn't have TASK_START register, please see the pictures.

how can I start PWM by timer?

thanks 

[K-night]

can I use this way to start PWM? but it is not successful

[Jørgen Holmefjord]

Hi,

As you can read in the PWM peripheral documentation, each PWM instance can set two separate sequences, SEQ[0] and SEQ[1]. These are started using TASKS_SEQSTART[0] and TASKS_SEQSTART[1]. See Figure 7 for a sequence diagram of the simplest PWM operation.

Best regards,
Jørgen

[K-night]

yes, but PPI only assigned one task, how can we assign two tasks(TASKS_SEQSTART[0],TASKS_SEQSTART[1])  by one PPI channel?

[Jørgen Holmefjord]

What are you trying to achieve? It is possible to assign a second task to be triggered by a PPI channel using the FORK, but I can't see why you would want to trigger both tasks at once. You can configure the PWM peripheral to play the sequences after each other by setting the LOOP and SEQ[n].CNT registers, see figure 6 and the code above in PWM peripheral documentation. If you want to trigger both SEQSTART tasks at different times, you need to use two separate PPI channels.

[K-night]

I only want to start two PWM synchronously, no delay time, so I will use PPI, and every PWM used complex playback function, SEQ[0] and SEQ[1] have data too. 

So I want to know how to trigger PWM by PPI, but PWM doesn't have TASK_START register as TIMER, you said only start TASKS_SEQSTART[0] and TASKS_SEQSTART[1] for PWM, these two registers needn't start synchronously. 

could you tell me how to trigger PWM by PPI?