Delay function in C

[Osama Mohammed]

hello, 

 

 

The delay function in c is not working with me and I don’t know why

 

this is the function that I am using : 

 

void MSDelay(unsigned int itime)

{

unsigned int i,j;

for (i=0;i<itime;i++)

for (j=0;j<1275;j++);

 

}

 

 

 

 

[SHAH DISHANT H.]

Hi,

 

We can no see anything wrong in this function..!!

 

Have u declred it before using ??

 

How you concluded that it is not working?

 

[Rupesh Anand]

 

IF YOU ARE USING IT ON PC 

THEN SPEED OF PC IS VERY HIGH AND GIVE YOU VERY SMALL DELAY…

TRY WITH HIGHER VALUES…. VERY HIGH

 

OR TOU CAN USE INTERNAL DELAY FUNCTION ….

[Osama Mohammed]

Yeah I know that is not wrong ,so this is why I am suprised , 

 

I concluded that is not working because when I put 1 second delay (1000) 

the code stuck in the delay function and doesn’t continue executing the code ,it is a 1 second delay though.

 

The problem is that I don’t know what’s the problem !! ,this caused many troubles for me , please could you suggest me a soultion

[Osama Mohammed]

Yes I declared it of course 

[SHAH DISHANT H.]

Send me entire code..!
I will try to solve…

 

This sounds an amazing issue..!!

Send the entire code pls..!!

[Ashutosh Bhatt]

see your function

if you are passing value 1000 to the function it will roll over for 1275000 times. ok?

so whats the problem? when it completes 1275000 cycles it will automatically come out of function and generate some delay. it may not be perfect 1 sec delay.

tell me how you run this delay function. step by step execution will take 1275000 steps. step over execution will take only 1 step

[Osama Mohammed]

This is the code of a setpper motor

I am using ISIS Proteus 

when I run the code with that delay function the execution us stuck in the function  !!

when I remove this delay function the code is executed normally and continually without stopping !

I tried to make many modfiications but nothing works 

 

#include <reg51.h>

msDelay(unsigned int);

 

#define stepperPort P2

 

void main (void)

{

 

stepperPort=0x03;

msDelay(4000);

stepperPort=0x06;

msDelay(4000);

stepperPort=0x0C;

msDelay(4000);

stepperPort=0x09;

msDelay(4000);

 

 

} 

 

 

 

msDelay(unsigned int tdelay)

{

 unsigned k,j;

 for(k=0;k<=tdelay;k++)

 for(j=0;j<=1275;j++);

 

}

[SHAH DISHANT H.]

Hi,

 

What is the frequency of your crystal ?

 

1275 value will give 1 milisecond delay i crystal of 11.0592MHz is sued and the code is compiled in GCC not in KEIL.

 

Try to reduce two values.

 

1. Instead of 1275, use low value.

2. Instead of msDelay(4000) also give low value like msDelay(10).

 

I had faced same issue. What was happening was, the delay was a lot more than what was expected. So I also thought that it is stucked in that function and not coming out of the loop.

 

Try with this and revert back.

[SHAH DISHANT H.]

Hi,

 

I have tried above function and tested on hardware…

 

Its working perfect AS EXPECTED…!!!

 

Issue seems in ur simulation only.,..!!

 

[Osama Mohammed]

 

 

 

no my simulation is working good without the delay function ,when I use the delay function it stops working 

 

 

anyway I tried to reduce the 1275 to 100 ,and it worked and it has worked well 

 

but know how could I calibrate the function to return 1 second delay when I enter 1000 ms to the function arguement msDelay(1000)

[SHAH DISHANT H.]

Hi,

 

To calibrate in ur expected way, you have to go for try and error method…

 

Observe the delay, change the value and keep testing unless you have got he exact value…!!

[Osama Mohammed]

thanks you guys, 

[Osama Mohammed]

Thank you guys,

[AJISH ALFRED]

Hi Osama,

It is due to the compiler optimisation. It simply optimise out the loop, which is not executing any useful statements. One solution is to remove all the optimisation options, or reduce the level of optimisation to zero. Still not working, this is how people do it, declare the local variables as volatile.

 

void MSDelay(unsigned int itime)

{

volatile unsigned int i,j;

for (i=0;i<itime;i++)

      for (j=0;j<1275;j++);

}

 

Which compiler are you using. If you are using keil, this may also work.

 

void MSDelay(unsigned int itime)

{

xdata unsigned int i,j;

for (i=0;i<itime;i++)

     for (j=0;j<1275;j++);

}

 

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