Let us now put on our "Geek glasses" and start monitoring PWM signals on Wokwi. For example, in Arduino UNO, you can find 6 PWM pins with the following properties. It's also important to note that Not all the PWM pins are created equal They may have different maximum frequencies and/or resolution. However, be aware that modifying the timer settings may cause certain Arduino functions to cease working properly.□ These pins are on the digital side of the Arduino UNO, and can be used for PWM output using the analogWrite() function in the Arduino programming language.ĭepending on the application, you may also require to change the frequency of the PWM signal, which is not something that you can do with the built-in function analogWrite(). On the Arduino UNO, the following pins are PWM compatible: 3, 5, 6, 9, 10, and 11. These digital pins are marked with the tilde ( ~) symbol next to them on the board. For example, the Arduino UNO has several pins capable of producing Pulse Width Modulation (PWM) signals. Most of the MCUs will have PWM-compatible pins. For example, if an LED turns on and off 10 times per second, its frequency is 10 Hz.įor a cyclic signal, such as an SPI Clock, the signal's frequency is 1/T, where T is the one-cycle period. How to calculate the frequency of a PWM signal?įrequency, measured in Hertz (Hz), is the number of repeating events per unit time. Changing the frequency of a PWM signal will not change the amount of power delivered to the load, but can affect the perceived brightness of a LED or the speed of a motor. Keep in mind that the duty cycle of a PWM signal is not related to its frequency. The image below shows a signal with four different duty cycle settings. If the PWM signal is on for 80% of the time and off for 20% of the time, the duty cycle is 80%.īy varying the duty cycle, you can increase or decrease the total power delivered to the load in small steps. So if the power is on for half the time and off for half the time, the duty cycle is 50%. The image below is a graphical illustration of the duty cycle. Then, divide the “ high” pulse width by the period( Tcycle) of the signal. To calculate the duty cycle, measure the signal's pulse width when it’s in the “ high” state, and the signal's total period. The amount of time the power is on compared to the amount of time it's off is called the " duty cycle." It's a handy technique to control the power and efficiency of different devices with a simple circuit. It's also used in things like dimmer switches for lights and speed controllers for electric vehicles. PWM is used in many electronic devices like fans, LEDs, and motors to control how fast or how bright they are. Like a blink, you can toggle the power on and off really fast. Imagine you have a light bulb that you want to control how bright it is. It's a way to control the amount of power going to an electronic device by turning it on and off very quickly. This article is part of a series of posts that help you to understand UART, SPI, I2C, PWM, WS2812 protocols, and more in a hands-on way with the help of a logic analyzer.
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