comparison include/PulseIn.h @ 193:3c3d14654b7f

Added PulseIn.

+/*
+ * PulseIn.h
+ *
+ *  Created on: 4 Feb 2016
+ *      Author: giulio
+ */
+
+#ifndef PULSEIN_H_
+#define PULSEIN_H_
+
+#include <BeagleRT.h>
+#include <vector>
+class PulseIn {
+private:
+	std::vector<int> _array;
+	int _pulseOnState;
+	int _digitalInput;
+	bool _pulseIsOn;
+	uint64_t _pulseStart;
+	uint64_t _lastContext;
+public:
+	PulseIn(){
+		_digitalInput = -1;
+	};
+
+	PulseIn(BeagleRTContext* context, unsigned int digitalInput, int direction=1){
+		init(context, digitalInput, direction);
+	};
+	/**
+	 * Initializes the PulseIn object. Also takes care of initializing the digital pin as input.
+	 *
+	 * If the object has been created with the default constructor, the user will
+	 * need to call init() before calling check() or hasPulsed().
+	 * @param digitalInput the digital input where to activate a pulse detector
+	 * @param direction the direction of the pulse,
+	 *  can be 1 to detect positive pulses, e.g.:( 0 0 0 0 1 1 0 0 0 0 0)
+	 *  or -1 to detect negative pulses, e.g.: ( 1 1 1 1 0 0 1 1 1 1)
+	 */
+	void init(BeagleRTContext* context, unsigned int digitalInput, int direction=1);
+
+	/**
+	 * Detects pulses.
+	 *
+	 * The user does not need to call this method as long as they call hasPulsed() at least once per context.
+	 * The rationale why we check() for pulses in a different method
+	 * than hasPulsed() is because user might not query for hasPulsed() every sample,
+	 * so we are safe so long as they call hasPulsed() or check() at least once per buffer.
+	 * Also, results are cached (i.e.: we do not check() for pulses twice for the same context.
+	 * context->audioSampleCount is used as an identifier.
+	 */
+	void check(BeagleRTContext* context);
+
+	/**
+	 * Looks for the end of a pulse.
+	 *
+	 * @param context the current BeagleRTContext
+	 * @param frame the frame at which to check if a pulse was detected.
+	 * @return the length of the pulse if a pulse ending was detected at sample n, zero otherwise.
+	 */
+	int hasPulsed(BeagleRTContext* context, int frame){//let's leave this in PulseIn.h to allow the compiler to optimize out the call.
+		if(_lastContext != context->audioSampleCount){ // check for pulses in the whole context and cache the result
+			check(context);
+		}
+		return _array[frame];
+	}
+	virtual ~PulseIn();
+};
+
+#endif /* PULSEIN_H_ */