runtime

[tony]

Hello,
i need to run a program for a specfic amount of time. e.g 5 secs, so i can calculate speed.

does anybody know the easiest way to do this,

will my counter still oerate when the counter is running or will it stop count to 5 and then move on to the next bit of code.

i'm using ccs, 16f877 and microchips ide board.

Thanks.

[SherpaDoug]

What does your program do?

If you have any serial output and you record it with something like something like terminal by Br@y++ that can timestamp the incomming data, you can use the timestamps to check the speed of your program. Note that adding print statements to your program may slow it down a lot.
_________________
The search for better is endless. Instead simply find very good and get the job done.

[Guest]

its a speedo,

it counts the revolutions,

then there is a sum, but time is one of the factors in the sum

[Thomas Blake]

Don't "run the program" for 5 seconds, run the counter/accumulator for 5 seconds.

Calculate the ints/second for the timer and clock speed you're using.
Compare it to the constant that equals 5 sec for that timer/clock.
If it's <, then continue to count and accumulate, else jump to an infinite loop or wait-for-switch loop.

Put thecounter/accumulator code in the main loop, not the timer interrupt handler. Use the timer/interrupt handler to set a go/stop flag instead.

Hope this helps.

[Guest]

you'll have to excuse my ignorance here i'm new enought pics.

i'm using a 20Mhz crytals,
so how would i calculate int ints/second.

by any chace would you have some examples of the code needed

[Neutone]

time=seconds;
While(time==seconds);
time=seconds;
while(time+5>seconds)
{ On_Now=Input(pin);
if(On_Now && Was_Off) ++pulse count;
Was_Off=!On_Now;
}

Take this and add an interupt driven time keeper.

[Guest]

using the speed.c example i think i have solved my problem

setup_timer_1(T1_INTERNAL|T1_DIV_BY_8);

long time;

set_timer1(0); // start counting


time=get_timer1();

now the only problem i have is trying to figure ou the follwoing line:

mph = 0.000009929*(float)time/3600.0; // calculate the time in hours
mph = distance/(63360.0*mph);

what is 0.000009929?
distance is a distance in inches and 63360=no of inches in a mile

[Guest]

anybody??

i'm still having problems