Is there a way to change PWM period through Processor Expert Interface?

[lfschrickte]

Hi,

I've just figured out I can't change the PWM Component Period during program execution through Processor Expert functions. Looking at the Timer Unit Component associated I realized the functions to change the timer period are "blocked" either, as this component is controlled by the PWM.

So, as I don't want to study the underlying PWM code (at least not right now), is there an easy way to change the PWM period? Maybe through some combination of PDD functions..

I'm using CodeWarrior 10.4 with Processor Expert. My MCU is a Kinetis L MKL14Z64VFM4.

Thank you very much, any help will be appreciated!

Luiz Fernando

[BlackNight]

Hi Luiz,

for non-Kinetis parts I'm using the PPG (Programmable Pulse Generation) component, but it looks this one is not available for Kinetis :-(

I'm wondering why.

Erich

[anthony_huereca]

Hi Luiz,

  Take a look at this tutorial: Tutorial: PWM with Processor Expert | MCU on Eclipse

  Let us know if that helps.

-Anthony

[lfschrickte]

Hi Anthony,

I've read this before, but as you can see it only explains how to set the initial period of the PWM, and not how to change it during program execution.

Is also mention the functions to change the duty cycle, but it is not enough for me.

I've a setup in which I need to have a way to change the buzzer frequency dinamically as I don't know which kind of buzzer will be installed (may have different product versions).

Thank you anyway!

Luiz Fernando

[BlackNight]

Hi Luiz,

what is the frequency of the PWM you need? Have you considered using a software PWM generation?

Erich

[lfschrickte]

Hi Erich,

Yes, I've considered setting up a timer to use the interrupts + IO as a PWM, however my application already has some critical interrupts being served and I don't want to have one more interrupt there for something like this. Indeed it is kind of frustrating that I can't set a PWM frequency in software because this looks so basic!

I'll hold this function in my app for now (switching the PWM frequency) as it is not mandatory. In the future I'll probably use the PDD functions and maybe some direct register manipulation to configure the PWM by myself.

Thank you!

Luiz Fernando

[BlackNight]

Yes, that tutorial shows how to set up the PWM period in the component. But at runtime it allows only changing the duty period/percent, and not the frequency of the PWM which what would be needed here.

Erich