Motorola SC140 User Manual

Setting Up the Stopwatch Timer Within an Application

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.