Diff: swpol.hpp

Revision:

0:24610a6f4e59

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/swpol.hpp	Tue Oct 24 14:01:04 2017 +0000
@@ -0,0 +1,70 @@
+#include "mbed.h"
+
+class SWPoll {
+    private:
+    enum State {LOW, LOW_DEBOUNCE, HIGH,HIGH_DEBOUNCE};
+    State state;
+    DigitalIn& sw;
+    DigitalOut& led;
+    Timer t; 
+
+    public:
+    //Constructor
+    SWPoll(DigitalIn& gpioIn,DigitalOut& gpioOut) : sw(gpioIn),led(gpioOut)
+    {
+        state = LOW;
+        t.reset();
+        led = 0;
+    }
+    //Deconstructor
+    ~SWPoll(){
+        //Shut Down
+        t.stop();
+        t.reset();
+        led = 0;
+    }
+    // API - poll the switches
+    // Use of a Timer to manage switch bounce
+    void poll(){
+        switch (state)
+        {
+        // waiting for switch to rise
+        case LOW:
+            if (sw == 1){
+                state = LOW_DEBOUNCE;
+                t.reset();
+                t.start();
+            }
+            break;
+        case LOW_DEBOUNCE:
+            if (t.read_ms() >= 200){
+                state = HIGH;
+                t.stop();
+                t.reset();
+            }
+            break;
+        case HIGH:
+            if (sw == 0) {
+                led = !led;
+                state = HIGH_DEBOUNCE;
+                t.reset();
+                t.start();
+            }
+            break;
+        case HIGH_DEBOUNCE:
+            if (t.read_ms() >= 200) {
+                state = LOW;
+                t.stop();
+                t.reset();
+            }
+            break;
+        default:
+            t.stop();
+            t.reset();
+            state = LOW;
+            break;
+        } //end switch
+        //This is a Mealy Machine - so no output logic follows
+                
+    }   
+};