execution time in milliseconds

Mir Dali

Hi,
I want to calculate the execution time in milliseconds of a code. what I wrote needs time.h, is there another way to do it without time.h:

clock_t start, end;
start=clock();
{
end=clock();
printf("execution time in milliseconds:%f\n", (end-start)/(double)clocks_PERS_SEC);
}
thanks a lot

over 13 years ago

0 Christian Willschek90 over 13 years ago

TI__Prodigy 705 points

Hi Mir,

there is an other way: just start your timer/counter, execute code and stop it again. That's it, that's all. I give you an example for the MSP430FRAM, using Timer_B registers.

/* ********* Timer_B Init (can also be done by Grace tool)  *********************** */

TB0EX0 = 0x7;
TB0CTL = CNTL_0 + TBSSEL_1 + ID_3 + MC_2 + TBIE;

/* *********** in your main ***************** */

TB0CTL &= ~(0x0030); //stop counter
TB0R = 0;  //set counter 0
TB0CTL |= MC_2; //start counter

   /* ************  your code to be measured **************** */

{}

TB0CTL &= ~(0x0030); //stop counter

Counter_B0_value = *(unsigned int *)0x03D0; //write counter value to variable

/* ******** end example ********* */

Do the Math:

time = Counter_B0_value * 1/(frequency) * prescaler

Be sure that you mind ALL prescaler! e.g. ACLK, Timer Input divider, TB0EX0, etc...

0 Antonio Espirito-Santo over 13 years ago in reply to Christian Willschek90

Expert 2855 points

Hi,

You can turn on a digital output when your code start and turn it off at the end. The time can be measured with an oscilloscope.

Best regards,
AES

0 Mir Dali over 13 years ago in reply to Antonio Espirito-Santo

Prodigy 65 points

Thanks a lot for your answer but actually and don't have an oscilloscope

0 Jens-Michael Gross over 13 years ago in reply to Mir Dali

Guru 227245 points

Mir Dali said:
actually and don't have an oscilloscope

Well, one really shuldn't start developing on a microcontroller without a scope. That's almost as programming a PC wihtout having a screen. Almost. :)

The problem is: teh MSP doesn't know about time. It only know clock cycles. You can count clock cycles, but you don't know how long a clock cycle is.
YOu ma yuse a quartz crystal and derive the MCU clockcycles from it, then you know how long a clock cycle is and can multiply it with the amount of clock cycles passed.
For counting clock cycles (up to 65535) you can use a timer, as suggested.

For a microcontroller, time really is relative.

0 Andy Neil over 13 years ago in reply to Jens-Michael Gross

Guru 35525 points

Jens-Michael Gross said:
one really shuldn't start developing on a microcontroller without a scope

Absolutely!

It's like taking up carpentry without a saw!

0 Jens-Michael Gross over 13 years ago in reply to Andy Neil

Guru 227245 points

Andy Neil said:
It's like taking up carpentry without a saw!

Well, Saw and drill are there, but the carpenter's rule is missing.
You can still build funiture, but if it come out bent and crooked, you don't know why or where to cut.

Well, I like this picture. Fits better than mine with the PC.

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execution time in milliseconds