In a typical microcontroller that might be used in an embedded application that needs to control a DC motor, you are likely to have an onboard timer or I/O coprocessor that can be used to generate the motor control signals. This type of feature should certainly be taken advantage of if it is available, it can potentially help you to avoid needing to use a more powerful (and more expensive) processor for a given application. But if you follow what we did here, you will understand the principle of DC motor control regardless of the implementation details that your application will dictate.
Now that we can turns things off and on and move things around we need to focus our attention on measuring how the real-world is responding to our manipulations. Without input we can't really control systems. Next time, we will begin looking at getting input from the environment.
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Skip Carter is a scientific and software consultant. He is the leader of the Forth Scientific Library project, and maintains the system taygeta on the Internet. He is also the President of the Forth Interest Group.