• State TI Thinks Resolved
  • Locked Locked
  • Replies 4 replies
  • Answers 1 answer
  • Subscribers 31 subscribers
  • Views 165 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.

TM4C1231H6PGE: Timer as PWM output chip to chip variance

Andrew Worwood
Prodigy 80 points
Part Number: TM4C1231H6PGE


Tool/software:

I am configuring a timer to be used as a pwm. I need to generate a 10.214kHz pwm signal, but I am finding that I am getting substantial variance in the frequency between my processors. As I am probing this pwm signal I am finding that 1 board will output a signal at around 10.29kHz while another will output around 10.04kHz. I need to get the variance from chip to chip to be much tighter than that. I would assume that the timers should be very accurate and precise across the different chips. What could explain the variance I am seeing.

  • 0
    TI__Guru**** 191906 points

    Hi,

      What is the SYSCLK frequency? What is the timebase clock you configure for PWM module? I don't think 10.214kHz is divisible by the PWM clock. 

    Andrew Worwood said:
    As I am probing this pwm signal I am finding that 1 board will output a signal at around 10.29kHz while another will output around 10.04kHz. I need to get the variance from chip to chip to be much tighter than that.

    Is the first board always producing 10.29kHz? Is the second board always producing 10.04kHz? 

    Do you have another board or two to establish some correlation?

    For experiment, can you try to create a PWM period that is divisible by the PWM clock? What is the result? I want to know if it is a one-off issue with one particular board only.

  • 0 in reply to Charles Tsai
    Prodigy 80 points

    I have the SysClk running at 80Mhz.

    Charles Tsai said:
    Is the first board always producing 10.29kHz? Is the second board always producing 10.04kHz? 

    Yes the frequencies of these 2 boards seems stable.

    Let me see if I can get my hands on a few more boards to check the frequency.

  • 0 in reply to Andrew Worwood
    TI__Guru**** 191906 points

    HI Andrews,

    Andrew Worwood said:
    Let me see if I can get my hands on a few more boards to check the frequency.

        I have not heard back from you. I will close the thread for now. If you have any update you can write to this post and the status will change to OPEN.

  • 0 in reply to Charles Tsai
    Prodigy 80 points

    I am still trying to get my hands on a few more boards. I will update once I am able to do that.