STM32 PRACTICAL COOKBOOK WITH DUMMY: The Ultimate Guide to STM32 Development a Tasty Collection of Recipes for Success (English Edition)

STM32 PRACTICAL COOKBOOK WITH DUMMY: The Ultimate Guide to STM32 Development a Tasty Collection of Recipes for Success (English Edition)

✔In the STM 32 timer series, and today we will see how to use the PWM input mode. I covered the PWM output in my previous project about the timers. And that's why I decided to go with the PWM input today, we will see how to measure the input frequency and the duty cycle using the PWM input mode. So let's start by creating the project in cube IDE.

✔I am using STM 32 F 446 R E, give some name to the project and click Finish. So first of all, I am selecting the external crystal for the clock. Let's see the clock configuration. Type in the crystal frequency of your controller. Choose this as per your board. Don't just use what I am using my board have eight megahertz crystal, choose the H S E for external crystal choose PCL K for PLL clock, type the frequency you want to run the controller at and hit enter.

✔That's all about the clock configuration. Now let's configure the timer. I am choosing timer one to provide the PWM signal PWM output has already been covered on the top right corner timer one is connected to a PV two clock which is running at 180 megahertz, I am choosing the auto reload period of 1800. So the output frequency will be 100 kilohertz This is it for the timer one. Now timer two is going to be used for the PWM input choose the clock sources internal clock and choose the combined channels as PWM input timer to channel one will be our main channel where we will provide the input clock you can see here the pin PA zero got selected. Now comes the parameters. Here I am keeping the prescaler zero.

✔So the timer clock will be same as a PB one and that is 90 megahertz. The auto reload is set to maximum value, this is a 32 bit register. And that's why this value is very high. If you have 16 bit register, this will be 65,535 So leave it to default. Next is the internal clock division. To understand this, we need to check the reference manual. Here in the control register one we have the clock division. This clock division basically sets up the dead time and sampling clock. The DT s clock decides how fast we want to sample the input signal. And here are the settings for the di t s clock. I am keeping it to no division and that means the DTS clock will be same as the internal clock we can skip the rest and come to the channel configuration.

✔Here the input trigger is Ti one F p one which means that the input from Channel One after the filter and polarity selection will be connected to the Capture One next we have is the parameters for channel one. The polarity is set to rising edge which means that this channel is going to measure the rising edges of the signal by sea selection is direct and we will connect the input signal directly to this channel.

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