topic Re: Is there a way to change PWM period through Processor Expert Interface? in Kinetis Microcontrollers

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

lfschrickte — Fri, 23 Aug 2013 17:45:45 GMT

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

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

anthony_huereca — Fri, 23 Aug 2013 18:05:17 GMT

Hi Luiz,

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

Let us know if that helps.

-Anthony

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

BlackNight — Fri, 23 Aug 2013 18:05:22 GMT

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

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

BlackNight — Fri, 23 Aug 2013 18:07:33 GMT

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

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

lfschrickte — Fri, 23 Aug 2013 18:09:56 GMT

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

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

BlackNight — Sat, 24 Aug 2013 06:48:07 GMT

Hi Luiz,

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

Erich

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

lfschrickte — Tue, 27 Aug 2013 13:01:24 GMT

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