Motorola ONCE SC140 - Manual (Page 11)

Setting Up the Stopwatch Timer Within an Application 7
Code 4. C Code for Clock-Cycle-to-Time Conversion
typedef enum { EONCE_SECOND, EONCE_MILLISECOND, EONCE_MICROSECOND } tunit;
unsigned long Convert_clock2time(unsigned long clock_ext, unsigned long clock_val,
short option)
{
unsigned long result;
switch(option)
{
case EONCE_SECOND:
result= clock_ext*MAX_32_BIT/CLOCK_SPEED + clock_val/CLOCK_SPEED;
break;
case EONCE_MILLISECOND:
result= clock_ext*MAX_32_BIT/(CLOCK_SPEED/1000)
+ clock_val/(CLOCK_SPEED/1000);
break;
case EONCE_MICROSECOND:
result= clock_ext*MAX_32_BIT/(CLOCK_SPEED/1000000)
+ clock_val/(CLOCK_SPEED/1000000);
break;
default: result=0; /* error condition */
break;
}
return result;
}
3.5 Putting it All Together
Code 5 depicts the use of the stopwatch timer using the routines that have been described so far.
Code 5. Use of Stopwatch Timer Functions
long clock_ext,clock_val,clock_cycle,time_sec;
...
EOnCE_stopwatch_timer_init(); /* Execute once per program execution */
...
EOnCE_stopwatch_timer_start();
/*
* Code whose execution time is measured goes here
*/
EOnCE_stopwatch_timer_stop(&clock_ext, &clock_val);
...
time_sec = Convert_clock2time(clock_ext, clock_val, EONCE_SECOND);
...
...
EOnCE_stopwatch_timer_start();
/*
* Code whose execution time is measured goes here
*/
EOnCE_stopwatch_timer_stop(&clock_ext, &clock_val);
...
time_sec = Convert_clock2time(clock_ext, clock_val, EONCE_SECOND);
The calls to the stopwatch timer functions can be made from different locations in the application code, not
necessarily from within one subroutine. The
EOnCE_stopwatch_timer_start () and
EOnCE_stopwatch_timer_stop () can be called more than once to measure the time consumed in different
modules as desired.