USING A GPIO PIN TO TAKE INPUT OF A PWM SIGNAL FOR MEASURING DUTY CYCLE AND FREQUENCY

[ritayandhara10]

I have a stm32g031k8 board. I was trying to give a pwm input signal like a square wave, measuring the frequency and duty cycle and generate pwm signal of that frequency and duty cycle using another timer. I was also changing the frequency and duty cycle of the input signal on the fly and it should change the output signal instantly. I was unable to do it. I was able to measure the frequency but nothing works. Please help me with the procedure. Thank You.

[Tesla DeLorean]

What Frequency are you attempting to measure.

Should use the PWM Input modes, when CH1 captures period and CH2 the duty. Look for examples using the various boards that come in the CubeG0 package. Perhaps also review the TIM Cook Book

[Sarra.S]

Hello @ritayandhara10, 

You can refer to the TIM_PWMInput example to measure the duty cycle, period

Since you're changing those parameters, you may want to use interrupts to capture the input signal edge and update PWM output signal

[ritayandhara10]

I am giving an input frequency of 10 khz to like 500khz. I was using the timer 1 channel 1 for capturing the rising edge and channel 2 for capturing the falling edges. Then using the timer 2 I was trying to generate a PWM signal

[ritayandhara10]

I am giving an input frequency of 10 khz to like 500khz. I was using the timer 1 channel 1 for capturing the rising edge and channel 2 for capturing the falling edges. Then using the timer 2 I was trying to generate a PWM signal. 

[nisarahmedmemon]

Hi @ritayandhara10,

To get real-time PWM tracking and generation working on your STM32G031K8, here’s a reliable method that works:

Configure TIM1 in PWM Input Mode

Use Channel 1 to capture the period (rising edge)

Use Channel 2 to capture the high time (falling edge)

Set TIM1 in slave reset mode so the counter resets on every rising edge

Use Interrupts to Capture the Signal

In the input capture callback, calculate:

Period = value from CH1

Duty = CH2 / CH1

Frequency = system clock / period

Call a function to update the output signal instantly

Generate Output PWM with TIM2

Set TIM2 ARR = period, CCR1 = high time

Start PWM on TIM2 Channel 1

This will recreate the input PWM signal with matched frequency and duty

Ensure Both Timers Use the Same Clock

Make sure TIM1 and TIM2 are running from the same clock domain (like APB or SYSCLK)

Use interrupts for real-time reaction; polling won’t work well with changing signals

This method handles 10 kHz to 500 kHz PWM inputs and updates the output smoothly.