Update CurieTimer1Interrupt.ino

libraries/CurieTimerOne/examples/CurieTimer1Interrupt/CurieTimer1Interrupt.ino

@@ -1,59 +1,71 @@
-//
-// Sketch: Timer1Interrupt.ino
-//
-//   This sketch demonstrates the usage of the ARC Timer-1.  It
-// uses timer-1 to blink the onboard LED, pin 13, at different
-// intervals (speed).
-//
+/*
+  Sketch: Timer1Interrupt.ino
 
-#include "CurieTimerOne.h"
+  This sketch demonstrates the usage of the Curie Timer One Library.
+  It uses timer-1 to blink the onboard LED, pin 13, at different
+  intervals (speed) in four steps.
+
+  You can see the time interval and the number of interrupt counted
+  in 10 seconds if you keep serial logging active, but this may require
+  a MASTER_RESET to reprogram the board. 
+
+  Blinking of the LED will start only when you open the  Serial Monitor
+  unless you comment the "#define SERIAL_PORT_LOG_ENABLE 1"; don't
+  forget to uncomment "CurieTimerOne.restart(time);"
 
-// Uncomment the following statement to enable logging on serial port.
-// #define SERIAL_PORT_LOG_ENABLE 1
+  created by Intel
+  Modified 14 March 2016
+  by Simone Majocchi
 
-const unsigned int oneSecInUsec = 1000000;  // A second in mirco second unit.
-unsigned int toggle = 0;
+  This example code is in the public domain.  
+*/
+
+#include "CurieTimerOne.h"
 
+// Comment the following statement to disable logging on serial port.
+#define SERIAL_PORT_LOG_ENABLE 1
 
-void timedBlinkIsr()
+const int oneSecInUsec = 1000000;   // A second in mirco second unit.
+bool toggle = 0;                    // The LED status toggle
+int time;                           // the variable used to set the Timer
+
+void timedBlinkIsr()   // callback function when interrupt is asserted
 {
-  digitalWrite(13, toggle ? HIGH : LOW);
-  toggle = (toggle + 1) & 0x01;
+  digitalWrite(13, toggle);
+  toggle = !toggle;  // use NOT operator to invert toggle value
 }
 
 void setup() {
 
 #ifdef SERIAL_PORT_LOG_ENABLE
   Serial.begin(115200);
-  while(!Serial);
+  while (!Serial);  //  wait for the serial monitor to open
 #endif
 
   // Initialize pin 13 as an output - onboard LED.
   pinMode(13, OUTPUT);
 }
 
 void loop() {
-  unsigned int i, time = oneSecInUsec;
-
-  CurieTimerOne.start(time, &timedBlinkIsr);
 
-  for(i=0; i < 4; i++, time >>= 1)
-  {
+  for (int i = 1; i < 9; i = i * 2) {
+    // We set a blink rate of 1000000, 500000, 250000, 125000 microseconds
+    time = oneSecInUsec / i; // time is used to toggle the LED is divided by i
+    CurieTimerOne.start(time, &timedBlinkIsr);  // set timer and callback
 
 #ifdef SERIAL_PORT_LOG_ENABLE
     Serial.print("The blink period: ");
     Serial.println(time);
 #endif
 
-    delay(10000);  // 10 seconds
+    delay(10000);  // 10 seconds of delay, regularly 'interrupted' by the timer interrupt
 
 #ifdef SERIAL_PORT_LOG_ENABLE
     Serial.print("Total number of ticks in 10 seconds: ");
-    Serial.println(CurieTimerOne.rdRstTickCount());
+    Serial.println(CurieTimerOne.rdRstTickCount());  // Reads and Resets tick count
     Serial.println("----");
 #endif
-
-    CurieTimerOne.restart(time);
+    // Uncomment the following line if the serial logging is disabled
+    // CurieTimerOne.restart(time);   // Restarts Timer
   }
 }
-