Diff: main.cpp

Revision:

0:8ab606ae2e1d

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Thu Jul 13 14:48:03 2017 +0000
@@ -0,0 +1,112 @@
+#include "mbed.h"
+
+DigitalOut  red_led(D7);
+DigitalOut  green_led(D5);
+DigitalIn   SW1(D4);
+DigitalIn   SW2(D3);
+//This is the solution based on the proposed flowchart.
+//The precise delay required may need adjusting
+
+Timer tmr1;
+
+#define WAITING4PRESS 0
+#define WAITING4BOUNCE_RISING 1
+#define WAITING4RELEASE 2
+#define WAITING4BOUNCE_FALLING 4
+
+int main() {
+    //Initial logging message
+    puts("START");
+    
+    //Initial state
+    red_led    = 0; //Set RED LED to OFF
+    green_led  = 1;
+    
+    //Switch state
+    int sw1State = 0;
+    
+    //Timers
+    tmr1.stop();
+    tmr1.reset();
+
+    //Initial logging message
+    puts("Entering state WAITING4PRESS");
+
+    //Main Polling Loop
+    while (true) {
+        
+        //Poll inputs (without blocking)
+        int sw1 = SW1;
+        
+        //Poll Timers
+        int tmr1Count = tmr1.read_ms();
+        
+        //LED1
+        switch (sw1State) {
+            
+        //Waiting for switch to be pressed
+        case WAITING4PRESS:
+
+            if (sw1 == 1) {
+                //Output: start timer
+                tmr1.reset();
+                tmr1.start();
+                
+                //Next state
+                sw1State =  WAITING4BOUNCE_RISING;  
+                puts("Entering state: WAITING4BOUNCE_RISING");
+            } 
+            break;
+            
+        //Waiting for 50ms to elapse
+        case WAITING4BOUNCE_RISING:      
+            if (tmr1Count > 50) {
+                //Outputs: Stop timer
+                tmr1.stop();
+                tmr1.reset();
+                //Next state
+                sw1State =  WAITING4RELEASE;  
+                puts("Entering state: WAITING4RELEASE");                
+            }    
+            break;
+        
+        //Waiting for switch to be released
+        case WAITING4RELEASE:
+            if (sw1 == 0) {
+                //Outputs: Toggle the LED and start timer
+                red_led = !red_led;
+                tmr1.start();                
+                //Next state
+                sw1State =  WAITING4BOUNCE_FALLING;  
+                puts("Entering state: WAITING4BOUNCE_FALLING");  
+            } 
+            break;
+            
+        //Waiting 50ms for switch bounce         
+        case WAITING4BOUNCE_FALLING:
+            if (tmr1Count > 50) {
+                //Outputs: Reset timer 1
+                tmr1.stop();
+                tmr1.reset();
+                
+                //Next state:
+                sw1State = WAITING4PRESS;
+                puts("Entering state: WAITING4PRESS"); 
+            }
+            break;
+            
+        default:
+            //Something has gone very wrong
+            tmr1.stop();
+            tmr1.reset();
+            red_led = 0;
+            sw1State = WAITING4PRESS;
+            puts("ERROR");
+            break;
+        
+        } //end switch
+        
+        
+    } //end while
+
+}
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