User manual

LPCXpresso Experiment Kit - User’s Guide
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frequency. It will be slightly lower since more than just delays are performed in the loop. If the delay is
2 us the frequency will be 5 kHz, if 3 us it will be 3.3 kHz, etc.
At what frequency does the LED flickering become apparent? __________________________
7.7.4 Lab 6d: PWM Control of two LEDs
In this experiment you shall create a program that controls the intensity of two LEDs with the help of
two trimming potentiometers. One loop shall now control two different PWM signals. As seen it
becomes more and more complicated to control multiple signals, especially if the signals have different
frequencies. The microcontroller is also fully occupied with generating the signals. If other work is
performed, the PWM signals will be affected (not correct duty cycle or frequency). This is why it is
typically simpler to let a timer generate the PWM signal, without software intervention (other than
setup). You will investigate this in more detail later on.