Diff: main.cpp

Revision:

0:8ee1b72f9a9b

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Thu Sep 24 12:32:36 2015 +0000
@@ -0,0 +1,49 @@
+#include "mbed.h"
+
+
+//Global objects
+DigitalOut myled(LED1);
+Serial pc(USBTX, USBRX);
+Ticker t;
+
+//Integer state of the LED
+//static makes it visible only within main.cpp
+static int state = 0;
+
+//Function prototype
+void doISR();
+
+int main() {
+   
+   //Initialise
+   pc.baud(115200);
+   t.attach(&doISR, 2);
+   myled = 0;
+    
+    //Main loop
+    while(1) {
+        
+        //Go to sleep and wait for an ISR to wake
+        sleep();    //At is says
+        
+        //At this point, the ISR has run
+        
+        //Update LED
+        myled = state;
+        
+        //Echo to terminal
+        if (state == 0) {
+            pc.printf("LED OFF\n");
+        } else {
+            pc.printf("LED ON\n");   
+        }
+    }
+}
+
+//Note - the ISR is short, and does NOT call functions
+//such as printf (it's actually unsafe to do so)
+//Always check a function is "reentrant" before calling it
+void doISR() {
+    //Toggle 0 to 1, or 1 to 0
+    state ^= 1;      
+}
\ No newline at end of file