Diff: main.cpp

Revision:

2:f86b1e3609b3

Parent:

1:22043b67c31c

Child:

3:3297ea6e3ae1

--- a/main.cpp	Fri Dec 04 17:38:02 2015 +0000
+++ b/main.cpp	Sat Dec 05 09:07:15 2015 +0000
@@ -1,88 +1,10 @@
-/** Revision 1: Building the class  */
+/** Revision 2: Separating the class declaration, implementation and main() function into files.  */
 
 #include "mbed.h"
+#include "HCSR04.h"
 
 Serial pc(USBTX, USBRX);    // communication with terminal
 
-class HCSR04 {
-    
-    public:
-    
-    /** Receives two PinName variables.
-     * @param echoPin mbed pin to which the echo signal is connected to
-     * @param triggerPin mbed pin to which the trigger signal is connected to
-     */
-    HCSR04(PinName echoPin, PinName triggerPin);
-    
-    /** Calculates the distance in cm, with the calculation time of 25 ms.
-     * @returns distance of the measuring object in cm.
-     */
-    float getDistance_cm();
-    
-    private:
-    
-    InterruptIn echo;       // echo pin
-    DigitalOut trigger;     // trigger pin
-    Timer timer;            // echo pulsewidth measurement
-    float distance;         // store the distance in cm
-    
-    /** Start the timer. */
-    void startTimer();
-    
-    /** Stop the timer. */
-    void stopTimer();
-    
-    /** Initialization. */
-    void init();
-    
-    /** Start the measurement. */
-    void startMeasurement();
-};
-
-
-HCSR04::HCSR04(PinName echoPin, PinName triggerPin) : echo(echoPin), trigger(triggerPin) {
-    init();
-}
-
-void HCSR04::init() {
-    /** configure the rising edge to start the timer */
-    echo.rise(this, &HCSR04::startTimer);
-    
-    /** configure the falling edge to stop the timer */
-    echo.fall(this, &HCSR04::stopTimer);
-    
-    distance = -1; // initial distance
-}
-
-void HCSR04::startTimer() {
-    timer.start(); // start the timer
-}
-
-void HCSR04::stopTimer() {
-    timer.stop(); // stop the timer
-}
-
-void HCSR04::startMeasurement() {
-    /** Start the measurement by sending the 10us trigger pulse. */
-    trigger = 1;
-    wait_us(10);
-    trigger = 0;
-    
-    /** Wait for the sensor to finish measurement (generate rise and fall interrupts).
-     *  Minimum wait time is determined by maximum measurement distance of 400 cm.
-     *  t_min = 400 * 58 = 23200 us = 23.2 ms */
-    wait_ms(25); 
-    
-    /** calculate the distance in cm */
-    distance = timer.read() * 1e6 / 58;
-    timer.reset(); // reset the timer to 0 after storing the distance
-}
-
-float HCSR04::getDistance_cm() {
-    startMeasurement();
-    return distance;
-}
-
 int main() {
     HCSR04 sensor(p5, p7);     // instantiate the sensor object
     while(1) {