Posts Tagged ‘Pulse Width Modulation’

Pulse Width Modulation (PWM) using the CCS Compiler

Pulse Width Modulation (PWM) signals in the embedded world are used all the time for a variety of reasons. One use is to communicate. For example, on most Ford cars and trucks the regulator communicates status of the alternator field coil back to the engine control module. If the duty cycle of the the PWM is between 10-90% it means that the alternator is working just fine and if it gets into the 0-10% or 90-100% there’s a problem. You could also control the power output of your headlights with PWM. This is how most daytime running lights are done. Some still switch into a resistor to knock down the power, but in todays world that’s just not efficient enough. We can also control the “theatre lighting” of our vehicle’s interior lights. Using PWM we can gradually brighten or darken the cars interior or we can take tricolor LEDs and change the color of our interior.

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