Alef Sin
A simple PWM decoder class. It is based on using 2 interrupts, one for rising and another for falling edges of the input pulse. This is a very simple approach, possibly accurate enough to decode RC receiver pulses.
Diff: pulse_decoder.h
- Revision:
- 0:b0ec6b86deaa
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/pulse_decoder.h Sun May 15 11:08:46 2016 +0000
@@ -0,0 +1,56 @@
+#ifndef PULSE_DECODER_H
+#define PULSE_DECODER_H
+
+/// @file pulse_decoder.h This library provides a simple PWM decoder class.
+///
+/// The approach is based on installing two interrupt routines for the rising and
+/// falling edges of an input pin and measuring the time between the two events.
+///
+/// Example:
+/// @code
+/// #include "mbed.h"
+/// void main()
+/// {
+/// pulse_decoder pulse(D7);
+///
+/// while(true) {
+/// printf("Pulse high = %5d low = %5d (us) Period = %5d\n",
+/// pulse.get_high_period(), pulse.get_low_period(),
+/// pulse.get_high_period() + pulse.get_low_period());
+/// wait(.2);
+/// }
+/// }
+/// @endcode
+
+class pulse_decoder {
+public:
+ ///Creates a pulse_decoder
+ ///@param[in] pin the input pin on the microcontroller
+ pulse_decoder(PinName pin);
+
+ ///Get the period of time that the pulse was in high state
+ ///@return the period in us
+ int get_high_period() const
+ {
+ return high_period;
+ }
+
+ ///Get the period of time that the pulse was in low state
+ ///@return the period in us
+ int get_low_period() const
+ {
+ return low_period;
+ }
+
+private:
+ InterruptIn interrupt;
+ Timer high_timer;
+ Timer low_timer;
+ volatile int high_period;
+ volatile int low_period;
+
+ void rising_edge();
+ void falling_edge();
+};
+
+#endif //PULSE_DECODER_H
\ No newline at end of file