Revision 1:221a6fd3d62f, committed 2017-03-16

Comitter:

martinsimpson

Date:

Thu Mar 16 10:38:40 2017 +0000

Parent:

0:2b4e5d360246

Commit message:

Modified for two wire connections 1.0b

Changed in this revision

--- a/main.cpp	Mon Oct 17 10:15:28 2016 +0000
+++ b/main.cpp	Thu Mar 16 10:38:40 2017 +0000
@@ -1,12 +1,16 @@
 /*
-    Simple Program to use SFR05 or SFR04 in Single Pin Mode
+    Simple Program to use SFR05 or SFR04
     Divide by 5.8 to give mm resolution from microseconds read of Echo pulse
-    Version 1.0a
+    Version 1.0b
     M.Simpson 17/10/2016
 */
 #include "mbed.h"
 
-DigitalInOut TriggerEcho(D8);                                   //Instance of the DigitalInOut class called 'TriggerEcho'
+#define TRIGGER_PIN D8                                          //Connect your Ultra Sonic device to these pins
+#define ECHO_PIN    D7                                          //Modify for you platform used 'Arduino' Header on F401RE NUCLEO
+
+DigitalOut Trigger(TRIGGER_PIN);                                //Instance of the DigitalOut class called 'Trigger'
+DigitalIn  Echo(ECHO_PIN);                                      //Instance of the DigitalIn class called 'Echo'
 
 Timer pulse;                                                    //Instance of the Timer class called 'pulse'
 
@@ -26,18 +30,16 @@
  
 float GetDistance(){                                            //Function Name to be called
      int EchoPulseWidth=0,EchoStart=0,EchoEnd=0;                //Assign and set to zero the local variables for this function
-     TriggerEcho.output();                                      //Make the DigitalInOut an Output to drive a signal
-     TriggerEcho.write(1);                                      //Signal goes High i.e. 3V3
+     Trigger=1;                                                 //Signal goes High i.e. 3V3
      wait_us(100);                                              //Wait 100us to give a pulse width
-     TriggerEcho.write(0);                                      //Signal goes Low i.e. 0V
-     TriggerEcho.input();                                       //Make the DigitalInOut an INPUT to accept a signal
+     Trigger=0;                                                 //Signal goes Low i.e. 0V
      pulse.reset();                                             //Rest the instance of the Timer Class
-     while(TriggerEcho.read()==0&&EchoStart<25000){             //wait for Echo to go high
+     while(Echo==0&&EchoStart<25000){                           //wait for Echo to go high
             EchoStart=pulse.read_us();                          //AND with timeout to prevent blocking!      
      }
-     while(TriggerEcho.read()==1&&(EchoEnd-EchoStart<25000)){   //wait for echo to return low
+     while(Echo==1&&(EchoEnd-EchoStart<25000)){                 //wait for echo to return low
         EchoEnd=pulse.read_us();                                //or'd with timeout to prevent blocking!   
      }
      EchoPulseWidth=EchoEnd-EchoStart;                          //time period in us
-     return (float)EchoPulseWidth/5.8f;                         //calculate distance in mm and reurn the value as a float
-}
\ No newline at end of file
+     return (float)EchoPulseWidth/5.8f;                         //calculate distance in mm and return the value as a float
+}