Let's Make Robots!

EDIT: Interrupts (in C) ?

Hi,

My question is if it is possible to estimate or calculate the time a µcontroller needs in order to execute a few commands. I'm trying to get exactly 1 second that a whole series of commands take, something like this (programmed in C):

while(j<time){

//several commands..

}

The whole while-loop should take exactly 1 second (to make a pretty correct clock), but I don't know if there is a way to calculate the time. I'm just doing trial and error right now but I guess there are better ways?

Thanks in advance!

_ZlaTanskY_

 

EDIT: I'm testing these interrupts now (in C language), found some tutorials on the internet, and got the timer working but the external interrupt doesn't work for me. The datasheet says that RA2-pin (I'm using a pickit2 with a PIC16F690) is the INT-pin.

Here's the code i'm using to light a led if the external interrupt on RA2-pin is activated:

#define _LEGACY_HEADERS
#include <htc.h>



__CONFIG(INTIO & WDTDIS & PWRTEN & MCLRDIS & UNPROTECT \
  & UNPROTECT & BORDIS & IESODIS & FCMDIS);



void interrupt LED(void){
    if (INTF){
        INTF = 0;
        RC0 = 1;
    }
}

main()
{

    PORTA = 0;              
    PORTC = 0;
    TRISA = 1;
    TRISC = 0;               
    INTCON = 0b10010000;
   
    while(1)               //  Loop Forever
    {
    } 
}

I use a male to male jumper cable to connect the Vdd to RA2, nothing happens. I tried putting an output high and connecting that output with RA2, nothing... What am I doing wrong?

Thanks in advance

_ZlaTanskY_

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Use the stopwatch in mplab. It's in the simulator under the the debugger menu. Make sure you set the frequency your processor is running at under debugger->settings. Set breakpoints at the start and end of the section of code you want to time.

Hm, I guess timer interrupts are the most precise way to go. I've been looking for a small amoutn of time at the debugger, but can't seem to get it working. Must be doing something wrong, will look at it when I've got some more spare time :)

@Oddbot; I'm using a PIC16f690 from microchip (1GHz), programming language is C. I have yet to determine how to use stuff like sleep() or millis() with it, same as the interrupts. So I'll have to take a look at those manuals I guess.

Thanks!

_ZlaTanskY_

Oke, so I've found a very nice tutorial about the timer AND using the debugger. If anyone else should have any problems, you can check this out:

http://ww1.microchip.com/downloads/en/DeviceDoc/51682A.pdf

Let's get this clock to working! ^^

Bump! I yelled too soon :)

EDIT: I meant 'EDIT', not 'bump'

it has been a while, but, I believe there is another flag that has to be set to enable interrupts.

Finally found out what the problem was!

I forgot the ANSEL = 0; command, which makes all the inputs digital... =)

Thanks for the replies everyone!