Revision 1:455a5cf52a84, committed 2013-07-25

Comitter:

pegcjs

Date:

Thu Jul 25 11:45:33 2013 +0000

Parent:

0:27e1de20d3cb

Commit message:

Demo code to use timer to time long times

Changed in this revision

diff -r 27e1de20d3cb -r 455a5cf52a84 main.cpp
--- a/main.cpp	Wed Feb 13 17:28:57 2013 +0000
+++ b/main.cpp	Thu Jul 25 11:45:33 2013 +0000
@@ -1,10 +1,42 @@
 #include "mbed.h"
- 
+//  Expanding the TIMER function to allow timing to very long times 
+// Demo written for lpc1768 to compare to onboard realtime clock.
+// uses highusecs to encode the top 32 bits of the timer output
+// and an int to uint conversion to get rid of the annoying negative.
+
 Timer t;
+
  
 int main() {
+set_time(1256729737);  // Set RTC time to Wed, 28 Oct 2009 11:35:37
+float umax=0,seconds=0;
+unsigned int realusecs=0,oldusecs=0,highusecs=0,minutes=0;;
+int dtime,usecs=0;
+
     t.start();
-    printf("Hello World!\n");
-    t.stop();
-    printf("The time taken was %f seconds\n", t.read());
+    usecs=t.read_us();
+    realusecs=(unsigned int)usecs;
+    time_t rtcstart = time(NULL);
+    printf("\n\n\r");
+    while(1)
+    {
+    wait(1);
+    oldusecs=realusecs;
+    usecs=t.read_us();
+    realusecs=(unsigned int)usecs;
+    //if(realusecs==0) t.reset(); // timer counts back up to 0 and finishes there
+   if(realusecs<oldusecs) { // its rolled over
+    highusecs++; // increment highbyte
+   }
+   seconds=((float)realusecs/1000000.0)+4294.967296*(float)highusecs;
+   minutes=(int)(seconds/60);
+    
+    if(umax<realusecs) umax=realusecs;
+    time_t rtcsecs = time(NULL);
+    dtime=rtcsecs-rtcstart;
+    printf("Seconds=%6.2f  mins=%d   realus=%u     hus=%u     us=%d       rtcs=%d         oldusecs=%u          \r",seconds,minutes,realusecs,highusecs,usecs,dtime,oldusecs);
+   
+    }
+
+    
 }