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Problems with PWM control of TM4C123x.

da
Expert 2780 points


Hello,

e2e.ti.com/.../2014404

TM4C123x (LM4F232) also confirmed the phenomenon that occurred in TM4C129x.

If PWM module is set to UP_Down mode and 1 is set in comparison register and
then changed to other numerical value, the PWM waveform is broken.

Is this a problem with the PWM module installed in the Tiva series?

Project

pwm_output_check_LM4F232.zip

Manual

pwm_duty_add_lm4f232.pdf

Regards,
Da

  • 0
    TI__Guru**** 244440 points
    Hello Da,

    There has been an issue identified for the behavior you mentioned. This is planned for an errata. In the meantime, can you please use DOWN count mode.

    Also regarding the first snapshot, are you using Synchronous mode or Immediate load of the values?
  • 0 in reply to Amit Ashara
    Expert 2780 points
    Hello Amit-san,

    I understood the problem of this PWM output as a problem of the PWM module in the Tiva series.
    There is no problem, do you?


    > Q: Synchronous mode or Immediate load of the values?

    A: Use Immediate load.



    Regards,
    Da
  • 0 in reply to da
    TI__Guru**** 244440 points
    Hello Da

    Thank you for the confirmation. Instead of using Immediate load, please use the load on a timeout or zero. This will ensure that the values are loaded only when the PWM counter is in a known state rather than during the count process.