Diff: main.cpp

Revision:

0:3506f73fe611

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Thu Sep 24 12:32:09 2015 +0000
@@ -0,0 +1,97 @@
+#include "mbed.h"
+
+//Global PWM object
+PwmOut pwmRed(D7);
+
+InterruptIn SWOn(D4);    //Fade ON
+InterruptIn SWOff(D3);    //Fade OFF
+
+int T = 100;    //100uS
+volatile int Tmark = 0; //0us
+volatile int delta = 1; //1us
+
+//Timer
+Ticker t;
+
+//Function prototype 
+void doTwinkle();
+void doSwitchON();
+void doSwitchOFF();
+
+//Flags
+volatile int switchONFlag=0;
+volatile int switchOFFFlag=0;
+volatile int tickerFlag = 0;
+
+int main() {
+    //Setup switch interrupts
+    SWOn.rise(doSwitchON);
+    SWOff.rise(doSwitchOFF);
+    
+    //Initial PWM state
+    pwmRed.period_us(T);
+    pwmRed.pulsewidth_us(Tmark);
+    
+    
+    printf("Ready\n");
+    
+    while(1) {
+        sleep();
+        
+        //Which interrupt occured?
+        if (switchONFlag == 1) {
+            switchONFlag = 0;   
+            delta = 5; 
+            t.attach(doTwinkle, 0.1);
+            printf("ON button pressed\n");
+        }
+        else if (switchOFFFlag == 1) {
+            switchOFFFlag = 0;
+            delta = -5;
+            t.attach(doTwinkle, 0.1);
+            printf("OFF button pressed\n");
+        }
+        
+        //Has ticker hit the end stop?
+        if (tickerFlag == 1) {
+            tickerFlag = 0;
+            delta = 0;      //Pedantic
+            t.detach();     //Turn off ticker
+            printf("Timer finished\n"); 
+        }
+        //Update PWM
+        pwmRed.pulsewidth_us(Tmark);
+        
+        printf("Tmark = %d\n", Tmark);    //Debug
+    }
+}
+
+void doSwitchON()
+{
+    switchONFlag=1;  
+}
+
+void doSwitchOFF()
+{
+    switchOFFFlag=1;
+}
+
+//ISR for Timer
+void doTwinkle()
+{
+    //Add on delta
+    Tmark += delta;
+    
+    //Cap at extremes
+    if (Tmark > 100) {
+        Tmark = 100;        
+    }
+    else if (Tmark < 0) {
+        Tmark = 0;
+    }
+    
+    //Check bounds 
+    if ((Tmark == 100) || (Tmark == 0)) {
+        tickerFlag = 1;
+    } 
+}
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