README

This sample program uses the class CUserTimer to implement software PWM to
control the output level of GPIO 22 and 23. If there is a LED connected (via a
resistor!) to one of these pins its brightness changes continuously. The state
of GPIO 23 is opposed to that of GPIO 22. When the LED at GPIO 22 is bright, the
LED on GPIO 23 is dark.

Software PWM can be used, if you need more than the two available hardware PWM
channels (see sample/13-pwmoutput) and for GPIO pins, which normally do not
support hardware PWM output. This sample uses two software PWM channels, but
more channels can be added if needed.

Before building the sample you may change its configuration (used GPIO pins, PWM
clock, PWM range) in the file kernel.cpp.

The sample has been tested successfully with a PWM clock of up to 500000 Hz
(with FIQ only) while the PWM signal has been checked with a digital
oscilloscope. It has not been tested with a servo, but should be usable to
control servos too.