Revision 0:67bcc374fa16, committed 2015-08-03

Comitter:

aagnone3

Date:

Mon Aug 03 18:26:05 2015 +0000

Commit message:

Initial revision.

Changed in this revision

diff -r 000000000000 -r 67bcc374fa16 PulseManager.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/PulseManager.cpp	Mon Aug 03 18:26:05 2015 +0000
@@ -0,0 +1,142 @@
+#include "PulseManager.h"
+
+PulseManager::PulseManager(PinName trigger, PinName echo):
+        startval(0), pulsetime(), runtime(), trigger(trigger), echo(echo)    {}
+
+
+PulseManager::~PulseManager() {}
+
+void PulseManager::write(int val) {
+    trigger = val;
+}
+
+void PulseManager::write_us(int val, int time)   {
+    // Write the complement of the high/low signal for a clean desired signal
+    trigger = !val;
+    wait_us(4);
+    
+    // Now write the desired signal for the given amount of time in us
+    trigger = val;
+    wait_us(time);
+    
+    // Write the complement again to end the signal write
+    trigger = !val;
+}
+
+int PulseManager::read_us()  {
+    // Reset the pulse timer
+    pulsetime.reset();
+    
+    // Wait for edge
+    startval = echo;
+    while (echo == startval)   {}
+    
+    // Measure pulse width
+    pulsetime.start();
+    while (echo != startval)  {}
+    pulsetime.stop();
+    
+    return pulsetime.read_us();
+}
+
+int PulseManager::read_us(int timeout)   {
+    // Reset timers, start runtime timer to detect timeout
+    runtime.reset();
+    runtime.start();
+    pulsetime.reset();
+    
+    // Wait for edge
+    startval = echo;
+    while (echo == startval)  {
+        if (runtime.read_us() > timeout)   return -1;
+    }
+    
+    // Measure pulse width
+    pulsetime.start();
+    while (echo != startval)   {
+        if (runtime.read_us() > timeout)   return -1;
+    }
+    pulsetime.stop();
+    
+    return pulsetime.read_us();
+}
+
+int PulseManager::read_high_us()  {
+    // Reset timer
+    pulsetime.reset();
+    
+    // Wait for next edge of echo signal
+    while (echo == 1) {}
+    while (echo == 0) {}
+    
+    // Measure pulse width of the echo pulse
+    pulsetime.start();
+    while (echo == 1) {}
+    pulsetime.stop();
+    
+    return pulsetime.read_us();
+}
+
+int PulseManager::read_high_us(int timeout)  {
+    // Reset runtime timer for timeout detection
+    runtime.reset();
+    runtime.start();
+    
+    // Reset pulseTimer
+    pulsetime.reset();
+    
+    // Wait for next edge of echo signal
+    while (echo == 1) {
+        if (runtime.read_us() > timeout)   return -1;
+    }
+    while (echo == 0) {
+        if (runtime.read_us() > timeout)   return -1;
+    }
+    
+    // Measure pulse width of the echo pulse
+    pulsetime.start();
+    while (echo == 1) {
+        if (runtime.read_us() > timeout)   return -1;    
+    }
+    pulsetime.stop();
+    
+    return pulsetime.read_us();
+}
+
+int PulseManager::read_low_us()   {
+    // Wait for next edge of echo signal
+    while (echo == 0) {
+    }
+    while (echo == 1) {
+    }
+    
+    // Measure pulse width of the echo pulse
+    pulsetime.start();
+    while (echo == 0) {}
+    pulsetime.stop();
+    
+    return pulsetime.read_us();
+}
+
+int PulseManager::read_low_us(int timeout)   {
+    // Reset runtime timer for timeout detection
+    runtime.reset();
+    runtime.start();
+    
+    // Wait for next edge of echo signal
+    while (echo == 0) {
+        if (runtime.read_us() > timeout)   return -1;
+    }
+    while (echo == 1) {
+        if (runtime.read_us() > timeout)   return -1;
+    }
+    
+    // Measure pulse width of the echo pulse
+    pulsetime.start();
+    while (echo == 0) {
+        if (runtime.read_us() > timeout)   return -1;    
+    }
+    pulsetime.stop();
+    
+    return pulsetime.read_us();
+}

diff -r 000000000000 -r 67bcc374fa16 PulseManager.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/PulseManager.h	Mon Aug 03 18:26:05 2015 +0000
@@ -0,0 +1,80 @@
+#ifndef MBED_PULSEMANAGER_H
+#define MBED_PULSEMANAGER_H
+
+#include "mbed.h"
+
+class PulseManager   {
+    public:
+        /** 
+        * Create a PulseManager object connected to the specified pin
+        * @param triggerPin output pin to use for generating a trigger signal
+        * @param echoPin input pin to use for measuring an echo signal
+        */
+        PulseManager(PinName triggerPin, PinName echoPin);
+        
+        /**
+        * Destructor to free allocated memory
+        */
+        ~PulseManager();
+        
+        /** 
+        * Set the value of the trigger pin
+        * @param val Value to set, 0 for LOW, otherwise HIGH
+        */
+        void write(int val);
+        
+        /** 
+        * Send a pulse of a given value for a specified time
+        * @param val Value to set, 0 for LOW, otherwise HIGH
+        * @param time Length of pulse in microseconds
+        */
+        void write_us(int val, int time);
+        
+        /** 
+        * Return the length of the next HIGH pulse in microsconds
+        */
+        int read_high_us();
+        
+        /** 
+        * Return the length of the next HIGH pulse in microseconds or -1 if longer than timeout
+        * @param timeout Time before pulse reading aborts and returns -1, in microseconds
+        */
+        int read_high_us(int timeout);
+        
+        /** 
+        * Return the length of the next LOW pulse in microsconds
+        */
+        int read_low_us();
+        
+        /** 
+        * Return the length of the next LOW pulse in microseconds or -1 if longer than timeout
+        * @param timeout Time before pulse reading aborts and returns -1, in microseconds
+        */
+        int read_low_us(int timeout);
+        
+        /** 
+        * Return the length of the next pulse in microsconds
+        */
+        int read_us();
+        
+        /** 
+        * Return the length of the next pulse in microseconds or -1 if longer than timeout
+        * @param timeout Time before pulse reading aborts and returns -1, in microseconds
+        */
+        int read_us(int timeout);
+        
+    private:
+    
+        /** Start value for echo pin to use for detecting a change */
+        int startval;
+        /** Timer for measuring pulse width */
+        Timer pulsetime;
+        /** Timer for detecting a timeout */
+        Timer runtime;
+        /** Pin handle for trigger pin */
+        DigitalOut trigger;
+        /** Pin handle for echo pin */
+        DigitalIn  echo;
+};
+
+#endif
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