topic TWR-KV46F150M : SDK Example : PWM Driver : No output Pulse on Submodule1(SM1) in Kinetis Microcontrollers

TWR-KV46F150M : SDK Example : PWM Driver : No output Pulse on Submodule1(SM1)

EmbedALM — Fri, 10 Jan 2025 06:53:23 GMT

Hello,

I am working with the TWR-KV46F150M evaluation board and using MCUXpresso IDE. I have downloaded and installed SDK version 2.8.0 for the TWR-KV46F150M. I am currently testing the PWM driver example by directly importing it from the SDK. i have attached the screen shot of the example project i have imported from SDK.

Steps Taken:

Imported the PWM driver example from the SDK.
Compiled the project and uploaded it to the board successfully without any errors.
Observed the PWM output on the assigned pins.

Issue:

I can see the PWM output on the pin corresponding to submodule 0, but there is no PWM output on the pin assigned to submodule 1.

Observations:

I confirmed that the example code is unmodified, and the project settings are default as provided in the SDK.
I verified the pin assignments and checked the schematics to ensure proper connections.
Submodule 0 is working as expected, but submodule 1 does not generate any signal on the corresponding pin.

Questions:

Is there an additional configuration required in the example to enable PWM output on submodule 1?
Could this issue be related to the board's hardware configuration, or is it likely a software setup issue?
Are there any known issues with the SDK version 2.8.0 for this board regarding PWM submodules?

Additional Information:

Board: TWR-KV46F150M
IDE: MCUXpresso IDE
SDK Version: 2.8.0
Example: PWM driver example (directly imported without modifications)

Thank you for your assistance. Any guidance or suggestions to resolve this issue will be greatly appreciated.

Re: TWR-KV46F150M : SDK Example : PWM Driver : No output Pulse on Submodule1(SM1)

Alice_Yang — Wed, 15 Jan 2025 02:27:11 GMT

Hello @EmbedALM

When running the demo, what message is displayed in the terminal?

And please refer to readme.txt to measure the signal using an oscilloscope.

* Probe the pwm signal using an oscilloscope
- At J501_9
- At J501_11
- At J501_30
- At J501_34

Alice

Re: TWR-KV46F150M : SDK Example : PWM Driver : No output Pulse on Submodule1(SM1)

EmbedALM — Wed, 15 Jan 2025 09:47:51 GMT

Hello Alice,

Thank you for your response. I checked the terminal, and it displays only "FlexPWM driver example". I also followed the instructions in the readme.txt and probed the pins using an oscilloscope as suggested.

Here’s what I observed:

The PWM signal is present at the pins corresponding to submodule 0.
No signal is observed at the pins assigned to submodule 1.

Additionally, I tried modifying the code by changing the clock setting for submodule 1. Specifically, I replaced:

"pwmConfig.clockSource = kPWM_Submodule0Clock;"

with

"pwmConfig.clockSource = kPWM_BusClock;"

After making this change, I observed that a pulse was generated on the submodule 1 pin as well.

Could you clarify:

Why submodule 1 does not output a signal when kPWM_Submodule0Clock is used as the clock source?

Re: TWR-KV46F150M : SDK Example : PWM Driver : No output Pulse on Submodule1(SM1)

Alice_Yang — Sat, 18 Jan 2025 08:55:11 GMT

Hello @EmbedALM

I have tested the PWM demo on my side, and I have the same issue as yours. Finally, I checked a thread to analyze this issue.

https://community.nxp.com/t5/Kinetis-Support/SDK-PWM-demo-error-on-some-PWM-pins/ta-p/1310710

Diagnosis

The root cause of the issue is that the demo configures the prescale divider for submodules 1 and 2 to a divide of two. In addition, these submodules use the Master Sync from submodule 0 for the initialization control. This, coupled with a clock that is twice as slow as submodule 0, causes submodules 1 and 2 to re-initialize before the output pins are able to change states.

Solution

Set the prescale divide for submodules 1 and 2 to a divide of one (instead of two).

I hope this information helps you.

Alice