How to detect two overlapping PWM signals (1Hz + 100Hz) on a single pin (S32K144)?

[Vaibhav_Gilbile]

Hello,

I’m working with the S32K144 and trying to detect two overlapping PWM signals on a single digital input pin:

• One signal is at 1 Hz

• The other is at 100 Hz

The two PWM signals are electrically mixed on the same pin (i.e., both are driving the same wire at the same time).

Attached pictures of frequency detection with 1hz(image1) and 100hz(image2).

We are considering interrupt based digital pin to capture Period(High Time + Low time) and frequency is calculated by 1/period.

Is there any recommended approach using NXP’s peripherals (FTM, LPIT, etc.) or external filtering for this scenario without modifying the hardware.

Any help, suggestions, or hardware guidance would be appreciated!

Thanks in advance.

[_Leo_]

Hi,

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

For input capture with FTM there are the following features (47.2.1 Features section of reference manual):

You should develop a custom algorithm based in these features to address input PWM overlapped measurement.

We do not have other particular feature for input PWM overlapped. Sorry for the inconvenient.

Hope it helps you.

Have a nice day!