topic Re: Two pwm out of phase in Kinetis Microcontrollers

Two pwm out of phase

EmanueleP — Fri, 26 Aug 2022 14:46:22 GMT

Hi, i have a kea 128 and i want to generate 2 out of phase PWM signals. I have selected FTM2 ch0 and ch1 for my purpose. PWM signals duty cycle must be 60%. Could you help me please?

Re: Two pwm out of phase

_Leo_ — Wed, 31 Aug 2022 00:13:12 GMT

Thank you so much for your interest in our products and for using our community.

In S32 Design Studio for ARM there is an example for PWM (FTM_PWT_kea128), which can serve as a reference.

Hope it helps you. Please let me know if you have more questions about it.

Have a nice day!

Re: Two pwm out of phase

EmanueleP — Wed, 31 Aug 2022 08:20:15 GMT

Thanks for your help, but i'm trying to configure the two PWM signals as shown in the picture.

I don't know if this type of configuration is supported by a single FTM module or if i'm forced to use 2 FTM modules: one channel of FTM0 in edge-aligned mode and one channel of FTM1 in center-aligned mode.

Thanks.

Re: Two pwm out of phase

_Leo_ — Thu, 01 Sep 2022 21:48:25 GMT

It is possible to configure the channels of the same FTM module differently. So yes, you only need one module.

However, for what you are looking for, it may be more convenient to make a Phase-shift PWM signal, for more details about this please refer to section 3.4 of application note AN5142.

Hope it helps you.

Re: Two pwm out of phase

EmanueleP — Fri, 02 Sep 2022 09:36:46 GMT

So, in this way i have to use 4 channels? In this way i lose 2 channel.

Thank you for your support.

Re: Two pwm out of phase

_Leo_ — Fri, 02 Sep 2022 20:20:07 GMT

Sorry, could you clarify your question please?

Re: Two pwm out of phase

EmanueleP — Mon, 05 Sep 2022 06:53:00 GMT

I would like to use two FTM channels to have 2 output singals with different phase. To use the application note method I need 4 FTM channels if I'm not mistaken. Now i'm try tu use ELSnA on one channel to set Low-true pulses (set Output on match-up) (26.3.6 chapter of kea128rm manual).

Re: Two pwm out of phase

EmanueleP — Mon, 05 Sep 2022 09:56:31 GMT

I solved the problem by setting a channel with ELSnA = 1. So the output channel become 1 at the match up, to the counter overflow