The K344 uses polling to capture PWM duty cycles (emphasis: no interruptions)

[jiafeimao]

I want to use 344MCU to capture a way of PWM duty cycle, it seems that only with interrupts + SAIC mode to achieve duty cycle capture, but I can not use interrupts. I figured out if I could configure two pins, one pin to capture the pulse width (IPWM mode) , the other pin to capture the pulse frequency (IPM mode) , then connect the two pins together and then connect the PWM waveform to be captured, ah, with the pulse width and pulse frequency to get the duty cycle.

What I don't understand is that if I connect the two pins of the MCU together, will the two pins interfere with each other while capturing the PWM signal?

[Robin_Shen]

Hi

Have you already referred to S32K344_Example_Emios_Icu_IPWM_measurement_DS34_RTD_100_v2? 

If you want to use polling method instead of interrupt method, please poll the status via Emios_Icu_Ip_GetInputState before calling Emios_Icu_Ip_GetDutyCycleValues.

Since I don't know the S32K3 RTD version you are using, I sent you the S32K344_Example_Emios_Icu_IPWM_measurement_S32DS35_RTD400.zip through private message. It is recommended to modify it to the polling mode based on project. Sorry, I haven't had time to test the polling method for you because I have been dealing with a lot of cases recently. If you still can't implement it after the modification, please let me know.

Best Regards,
Robin
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[jiafeimao · Accepted solution]

I tested the example, found that the PWM cycle and duty cycle can be obtained under interruption conditions.

Afterwards, I regenerated the code and removed the interrupt enable and interrupt interface. In non interrupt situations, both the cycle and duty cycle were returned as 0.

In addition, I use IPWM and IPM to capture a PWM signal (two pins). IPWM obtains a high level, IPM obtains a cycle, and the duty cycle can be obtained without any interruption.I think this is the only way to obtain the PWM duty cycle without any interruption. Here is my approach:

1.Pin settings:

2.Emios_Mcl_Ip:

3.Emios_Icu:

4.demo init ipwm and ipm:

5.demo get duty: