Diff: main.cpp

Revision:

0:8888b2ad5510

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Wed Dec 09 14:41:51 2020 +0000
@@ -0,0 +1,50 @@
+/* 
+
+2645_Ticker
+
+Sample code from ELEC2645
+
+Demonstrates how to use a ticker to generate a periodic timer interrupt
+
+(c) Craig A. Evans, University of Leeds, Jan 2016
+
+*/ 
+
+#include "mbed.h"
+
+// Create objects for ticker and red LED
+Ticker ticker;
+DigitalOut led(LED1);
+
+// flag - must be volatile as changes within ISR
+// g_ prefix makes it easier to distinguish it as global
+volatile int g_timer_flag = 0;
+
+// function prototypes
+void timer_isr();
+
+int main()
+{
+    // set-up the ticker so that the ISR it is called every 0.5 seconds
+    ticker.attach(&timer_isr,0.5);
+    
+    while (1) {
+
+        // check if flag is set i.e. interrupt has occured
+        if (g_timer_flag) {
+            g_timer_flag = 0;  // if it has, clear the flag
+            printf("Tick \n");
+            // DO TASK HERE
+        }
+
+        // put the MCU to sleep until an interrupt wakes it up
+        sleep();
+
+    }
+}
+
+// time-triggered interrupt
+void timer_isr()
+{
+    g_timer_flag = 1;   // set flag in ISR
+}