Diff: Timer.cpp

Revision:

2:e26c096f1946

Child:

3:88da6c0412b0

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Timer.cpp	Sun Dec 30 04:58:42 2012 +0000
@@ -0,0 +1,111 @@
+#include "Timer.h"
+//This class uses Timer 1
+
+// static data initialization  (only called once)
+bool Timer::timer1initialized = false; 
+int Timer::resolution = 1000000;
+
+void Timer::initTimer1(int res) //microseconds accuracy
+{
+    uint8_t pclk;
+    uint32_t pclkdiv = (LPC_SC->PCLKSEL0 >> 4) & 0x03; //PCLK for Timer 1 (page 56)
+
+    switch ( pclkdiv ) // table 42 (page 57 in user manual)
+    {
+      case 0x00:
+      default:
+            pclk = 4;
+            break;
+      case 0x01:
+            pclk = 1;
+            break;
+      case 0x02:
+            pclk = 2;
+            break;
+      case 0x03:
+            pclk = 8;
+            break;
+    }
+
+    LPC_TIM1->TCR = 0x02;           /* reset timer */
+    LPC_TIM1->PR  = (SystemCoreClock / (pclk * res)); //default: microsecond steps
+    LPC_TIM1->MR0 = 2147483647;             /* highest number a 32bit signed int can store (for us ~ 35.79 minutes, or, for ms ~ 596.52 hours ) */
+    LPC_TIM1->IR  = 0xff;           /* reset all interrrupts */
+    LPC_TIM1->MCR = 0x02;           /* reset timer on match */
+    LPC_TIM1->TCR = 0x01;           /* start timer */
+
+    /* The timer simply goes on forever! It just resets itself when it hits the max number for TC */
+    timer1initialized = true;
+    resolution = res;
+}
+
+Timer::Timer()
+{        
+    if(!timer1initialized)
+    {
+        initTimer1(resolution); //default resolution
+    }
+    
+    starttime = 0;
+    stoptime = 0;
+    running = false;
+}
+
+//for when we want to allow lower counting resolution, eg. milliseconds
+//so we can count longer than the 35 minutes with microsecond resolution
+Timer::Timer(int res) // millisecond, res = 1000
+{   
+    if(!timer1initialized)
+    {
+        initTimer1(res); //custom resolution
+    }
+    
+    starttime = 0;
+    stoptime = 0;
+    running = false;
+}
+
+void Timer::start()
+{
+    starttime = LPC_TIM1->TC;
+    stoptime = 0; //clear previous stoptime
+    running = true;
+}
+
+void Timer::stop()
+{
+   stoptime = LPC_TIM1->TC;
+   running = false;
+}
+
+void Timer::reset()
+{
+    if(running)
+    {
+        starttime = LPC_TIM1->TC;
+    }
+    else
+    {
+        starttime = 0;
+    }
+    
+    stoptime = 0;
+}
+
+float Timer::read()
+{
+    if(running)
+    {    
+        int currenttime = LPC_TIM1->TC;
+        return (currenttime - starttime) / (resolution*1.0);
+    }
+    else // compare startime and stoptime
+    {
+        return (stoptime - starttime) / (resolution*1.0);
+    }
+}
+
+Timer::operator float()
+{
+    return read();
+}