Diff: main.cpp

Revision:

0:ce9972ee58a1

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Wed Mar 09 12:47:33 2016 +0000
@@ -0,0 +1,111 @@
+#include "mbed.h"
+
+// There is a LOT of code repetition here.
+// Following bad practise, you can almost copy and paste the code for the red LED to add the greedn
+// Further task: Consider ways to reduce this to make it simpler to maintain.
+
+void sw1TimeOutHandler();
+void sw1RisingEdge();
+void sw1FallingEdge();
+void sw2TimeOutHandler();
+void sw2RisingEdge();
+void sw2FallingEdge();
+
+#define EDGE_RISEN 1
+#define EDGE_FALLEN 0
+
+//Global Objects
+DigitalOut  red_led(D7);
+DigitalOut  green_led(D5);
+InterruptIn   sw1(D4);
+InterruptIn   sw2(D3);
+
+Timeout sw1TimeOut;             //Used to prevent switch bounce
+Timeout sw2TimeOut;
+int sw1State = EDGE_FALLEN;     //Initial state for switch 1
+int sw2State = EDGE_FALLEN;
+
+//Interrupt service routine for handling the timeout
+void sw1TimeOutHandler() {
+    sw1TimeOut.detach();            //Stop the timeout counter firing
+
+    //Which event does this follow?
+    switch (sw1State) {
+    case EDGE_RISEN:    
+        sw1.fall(&sw1FallingEdge);  //Now wait for a falling edge
+        break;
+    case EDGE_FALLEN:
+        sw1.rise(&sw1RisingEdge);   //Now wait for a rising edge
+        break;
+    } //end switch 
+}
+
+//Interrupt service routine for a rising edge (press)
+void sw1RisingEdge() {
+    sw1.rise(NULL);             //Disable detecting more rising edges
+    sw1State = EDGE_RISEN;      //Flag state
+    sw1TimeOut.attach(&sw1TimeOutHandler, 0.2);    //Start timeout timer
+}
+
+//Interrupt service routive for SW1 falling edge (release)
+void sw1FallingEdge() {
+    sw1.fall(NULL);                         //Disable this interrupt
+    red_led = !red_led;                     //Toggle LED    
+    sw1State = EDGE_FALLEN;                 //Flag state
+    sw1TimeOut.attach(&sw1TimeOutHandler, 0.2);    //Start timeout counter    
+}
+
+void sw2TimeOutHandler() {
+    sw2TimeOut.detach();            //Stop the timeout counter firing
+
+    //Which event does this follow?
+    switch (sw2State) {
+    case EDGE_RISEN:    
+        sw2.fall(&sw2FallingEdge);  //Now wait for a falling edge
+        break;
+    case EDGE_FALLEN:
+        sw2.rise(&sw2RisingEdge);   //Now wait for a rising edge
+        break;
+    } //end switch 
+}
+
+//Interrupt service routine for a rising edge (press)
+void sw2RisingEdge() {
+    sw2.rise(NULL);             //Disable detecting more rising edges
+    sw2State = EDGE_RISEN;      //Flag state
+    sw2TimeOut.attach(&sw2TimeOutHandler, 0.2);    //Start timeout timer
+}
+
+//Interrupt service routive for SW1 falling edge (release)
+void sw2FallingEdge() {
+    sw2.fall(NULL);                         //Disable this interrupt
+    green_led = !green_led;                //Toggle LED    
+    sw2State = EDGE_FALLEN;                 //Flag state
+    sw2TimeOut.attach(&sw2TimeOutHandler, 0.2);    //Start timeout counter    
+}
+
+//Main - only has to initialise and sleep
+int main() {
+    //Initial logging message
+    puts("START");
+    
+    //Initial state
+    red_led     = 0; //Set RED LED to OFF
+    green_led   = 0;
+    
+    //Configure interrupts, wait for first rising edge
+    sw1.rise(&sw1RisingEdge);
+    sw2.rise(&sw2RisingEdge);
+    
+    //Main Polling Loop
+    while (true) {
+        
+        //Put CPU back to sleep
+        sleep();
+        
+        //You can ONLY reach this point if an ISR wakes the CPU
+        puts("ISR just woke the MPU");
+        
+    } //end while
+
+}