topic Re: Enabling two Complimentary PWM on KL16 with TPM in Kinetis Microcontrollers

Enabling two Complimentary PWM on KL16 with TPM

grushbrush — Wed, 06 Dec 2017 21:44:54 GMT

We have a Kinetis KL16Z128

We have the requirement to run two PWM signals at the same time.

One of the signal's polarity should start high, and the other starts low.

1) It seems there is no way to make the initial polarity high. Why is this?

2) We get an "undefined error" when trying to use PWM_Enable and Disable in our main.c on the Processor Expert PWM components.

Thank you! michaelgoudey BlackNight

Re: Enabling two Complimentary PWM on KL16 with TPM

michaelgoudey — Wed, 06 Dec 2017 23:45:34 GMT

Hi Ethan,

The KL16 TPM does not support 'high' initial polarity. Erich has a post on the topic.

Tutorial: PWM with Processor Expert | MCU on Eclipse

The problem is the PWM component doesn't support initial high. See the community link below which applies to FRDM-KL25Z and would apply to KL16 as well.

https://community.nxp.com/thread/339065

If you have selected "Enabled in init. code" for the PWM, this is done automatically and you should not enable separately in your code. If you do, Deinit should be called first.

Regards,
Michael Goudey

Re: Enabling two Complimentary PWM on KL16 with TPM

BlackNight — Fri, 08 Dec 2017 06:44:37 GMT

I don't have that KL16, but I see it is possible to set the initial polarity here:

To have the Enable and Disable available, you should turn them on with the context menu:

Erich

Re: Enabling two Complimentary PWM on KL16 with TPM

grushbrush — Mon, 11 Dec 2017 21:01:57 GMT

We have a motor that has two connections. It requires two PWM signals. The first signal has to start high. Is there any way we can drive this motor? There has got to be, this is a really simple thing. Can you please help us with this one?

Also, is there any way we can start one PWM at a different time than the second PWM? We want to try offsetting the start time for the second PWM in relation to the first PWM.