Diff: Parallax_X-Band.cpp

Revision:

2:6e294a3a74f8

Child:

3:b9e54783e0c5

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Parallax_X-Band.cpp	Sun Mar 08 20:01:37 2015 +0000
@@ -0,0 +1,109 @@
+#include "Parallax_X-Band.h"
+
+/** 
+* Initialize the xband motion detector and setup interrupts. Default is to be disabled.
+*
+* @param pin_enable Enable pin. Connected to EN on xband.
+* @param pin_input Data pin. Connected to OUT on xband.
+*/ 
+xband::xband(PinName pin_enable, PinName pin_input)
+    : _pin_enable(pin_enable), _pin_input(pin_input)
+{
+    // Default disabled.
+    _pin_enable=0;
+    
+    // Initialize count to be 0.
+    _count = 0;
+    
+    // No velocity reading has been calculated yet.
+    _velocityflag = false;
+    
+    // Setup interrupt on input pin.
+    _pin_input.rise(this, &xband::xband_RiseISR);
+    
+    // Timer for count differntiation.
+    _sampletime.start();
+
+    // Interrupt to calculate the velocity. Default every half second.
+    _samplevelocity.attach(this, &xband::xband_velocityISR, 0.5);
+}
+
+/**
+* Destructor
+*/
+xband::~xband() {}
+
+/** 
+* Subroutine to enable and disable the detector.
+*
+* @param enable True to enable, False to disable.
+*/ 
+void xband::enable(bool enable)
+{
+    _pin_enable=enable;
+}
+
+/** 
+* Interrupt service routine to collect data on the input pin.
+*/ 
+void xband::xband_RiseISR()
+{
+    // Increment count for every positive rising edge pulse on input pin.
+    _count++;
+}
+
+/** 
+* Interrupt service routine to calculate the velocity of the moving object.
+*/ 
+void xband::xband_velocityISR()
+{
+    // Differentiate current count value change during time slice.
+    _velocity = ((_count - _lastcount)/(_sampletime.read_ms()/1000.0));
+    
+    // Set a flag to indicate a new velocity calculation.
+    _velocityflag = true;
+    
+    // Reset timer for next differentiation.
+    _sampletime.reset();
+    _lastcount = _count;
+}
+
+/** 
+* Get count value and return it as an integer.
+*
+* @return Integer value of current count.
+*/ 
+int xband::read_count()
+{
+    return _count;
+}
+
+/** 
+* Get current velocity reading. Sets a flag to false to indicate a stale value after reading.
+*
+* @return Float value of currently measured velocity.
+*/ 
+float xband::read_velocity()
+{
+    _velocityflag = false;
+    return _velocity;
+}
+
+/** 
+* Resets the count variable to 0.
+*/ 
+void xband::reset_count()
+{
+    _count = 0;
+}
+
+/** 
+* Checks if a new velocity value has been calculated.
+*
+* @return True if a new velocity value is avaliable. False if the value has
+* already been read.
+*/ 
+bool xband::velocityack()
+{
+    return _velocityflag;
+}
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