8051 external interrupt problem

[0killingsoul0]

View attachment one.bmpHi all. I am getting a weird type of error.Its a simle code to count the interrupts in ten second. When i physically implement the circuit on bread board , its counting more low level signals ( grounding the pin 3.2) . Like if i ground it once it should count/display one but its displaying larger value. This code is working perfectly on proteus and on trainer kit. But dont know what i am missing in circuit its not working.



View attachment one.bmp


View attachment one.rar

 				 		   // Program to interface single seven segment
 
#include<reg51.h>
 char num[]={0x40,0xF9,0x24,0x30,0x19,0x12,0x02,0xF8,0x00,0x10};		// Hex values corresponding to digits 0 to 9


unsigned int counter;
unsigned int counter1;
unsigned int counter2;
unsigned int counter3;

unsigned int counter4;



delay_ms(int time)		// Time delay function
{
	int i,j;
 	for(i=0;i<time;i++)
  	for(j=0;j<1275;j++);
}
	



 ////////////// iNTERUPT tO cOUNT
void ex0_isr (void) interrupt 0
{
	counter++;   // Increment the count
}



void countdelay(void)
{
	TMOD=0x01;
	TL0=0x00;
	TH0=0x00;
	TR0=1;
	while (TF0==0);
	TR0=0;
	TF0=0;
}


void main()
{  
unsigned int c;	
 

 IT0 = 1;   // Configure interrupt 0 for falling edge on /INT0 (P3.2)
	  EX0 = 1;   // Enable EX0 Interrupt
    
	  EA = 1;    // Enable Global Interrupt Flag
	


  //  counter=6709;

	P0=num[0]; 
		P1=num[0]; 
		P2=num[0];



	while(1)
	{
	

		


			 for(c=0;c<154;c++)
		  {
		    countdelay();		 // 65.535 ms delay
		  }

	
		 
		 
		 
	
		 
	
	
		  counter1=counter%10;

	
	
		  counter2=(counter/10)%10;

	      counter3=(counter/100)%10;
	

		  

     	P0=num[counter1]; 
		P1=num[counter2]; 
		P2=num[counter3]; 
		counter=0;
	}

}

 

[Kurenai_ryu]

could you post the trainer kit you were using? (if you have an schematic, post it too) as it seems a bit more complex than your simple push button...

in simulation this will work with no flaws, but in a real implementation the bouncing and debouncing of the push button WILL ALWAYS produce extra pulses for the microcontroller.
there you implement a debouncing circuit.
you could search more, but the one i used a lot is the **broken link removed** as it will do the job.


now, maybe you can improve a little with an external pull-up for the push-button, something like 4k7 or 10k ohm,
otherwise you need to implement this in software, but it's a difficult task as you wanted to count via interrupt.

That's why me would like to see which development kit you used and worked...

 

[manrayap]

Hi,

Initial value for variable counter in main program should be set to 0. ie. counter=0; . Tq.