• State Resolved
  • Locked Locked
  • Replies 6 replies
  • Answers 1 answer
  • Subscribers 83 subscribers
  • Views 646 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TMS320F280049C: How to trip EPWM at every third event generated from CMPSS module

Rayna Wang
Expert 3680 points

Part Number: TMS320F280049C

Hi Expert,

In customer's application, 

  1. there's a no fixed cycle external signal which input to CMPSS positive side. 
  2. when external signal exceed CMPSS reference DAC value, CMPSS outputs signal and transfers to DC module to TZ module, and every third exceeding event to control EPWM to high state. 

I have checked the digital filter function, however it's based on SYSCLK which is not satisfied with "no fixed cycle" demand, otherwise, I'm not sure if event filter in DC module could be used for this.

Do you have any idea that how to achieve the above requirements? Thanks!

Best Regards

Rayna

  • 0
    TI__Mastermind 24095 points

    Hi Rayna,

    Rayna Wang said:
    there's a no fixed cycle external signal which input to CMPSS positive side. 


    What exactly do you mean by no fixed cycle? Do you mean asynchronous trip?

    Rayna Wang said:
    I have checked the digital filter function, however it's based on SYSCLK which is not satisfied with "no fixed cycle" demand, otherwise, I'm not sure if event filter in DC module could be used for this.


    Have you looked at the Valley Switching block? This may meet your function requirement of taking action on every nth event. Please look through this function and let me know. It's still a clock based filter though. Details in "Valley Switching" chapter of TRM.

  • 0 in reply to Subrahmanya
    TI__Expert 3680 points

    Hi Subrahmanya,

    Yeah, the external signal is not regular changing, so we could not filter the event based on system clock. The function requirement is just like that generate an interrupt on every third event in Event trigger submodule.

    You mean that the Valley Switching block is also a clock based filter? So how to meet the function requirement of taking action on every 3th event?

    Best Regards

    Rayna

  • 0 in reply to Rayna Wang
    TI__Mastermind 24095 points

    Rayna,

    Yes - all the filters are clock based including the valley switching. But it has the capability to keep track of the number of edges.

    What is the issue in using clock based logic?

  • 0 in reply to Subrahmanya
    TI__Mastermind 24095 points

    Hi Rayna,

    Did you get a chance to check the valley switching logic for this purpose?

  • 0 in reply to Subrahmanya
    TI__Expert 3680 points

    Hi Subrahmanya,

    Thanks for your support! Customer is evaluating the valley switching function.

    Best Regards

    Rayna

  • 0 in reply to Rayna Wang
    TI__Mastermind 24095 points

    Hi,

    Let us know if the customer could use this option.
    I'll close this thread. You can create a new post or update here based on customer response.