How Pulse Width Modulation (PWM) Works + Example | Embedded Systems Explained

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Learn how to setup microcontrollers to output pulse width modulated (PWM) signals and watch until the end for a real life example with an MSP430!
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0:00 Intro & Embedded Systems Explained
1:16 What are Capture and Compare Modules
2:03 Timer Setup for PWM Output
3:09 Capture and Compare Module Setup for PWM Output
5:05 MSP430 PWM Example with Code Overview & Oscilloscope Waveform
7:33 Applications of PWM (Pulse Width Modulation)

My name is Fabi and I am an Engineer and Tech Enthusiast from Romania. On my YouTube channel I do thorough reviews of gadgets, showcase my programming projects and show you which cars I am driving.

This video is part of my Embedded Systems Explained series.

In today's video we'll be talking about the compare mode of the timer capture and compare modules, capable of outputting signals with a modifiable duty cycle, hence the name, pulse width modulation.

Capture and compare modules are auxilliary to timers, in architectures like the MSP430, each timer has up to 6 CCPs associated, while PIC microcontrollers have CCPs which can work with different timers. Either way, you have a set of registers governing the timer itself and one or more registers for settings regarding to the CCP.

So, with the CCP you first have to specify that it will work in compare mode and then the output mode. This means that once you set everything up, the capture and compare module will be capable of generating the PWM with no need for extra code. While you could also generate the signal through code when the interrupts are generated, this is not necessary.

The output mode defines what happens to the output signal when the timer reaches the value set in the timer's register and what happens to the output signal when the timer reaches the value set in the capture and compare module. As you can see from the screenshot I took from the user guide of the MSP430G2553 microcontroller, 4 output modes can be useful when trying to generate PWMs: Toggle/Reset, Set/Reset, Toggle/Set, Reset/Set. The output signal will have an edge when the timer reaches the value set in the timer's register and when the timer reaches the value set in the CCP register.

Видео How Pulse Width Modulation (PWM) Works + Example | Embedded Systems Explained канала TheFabytm