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plz plz help controller not working to drive dc motor

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tech_pro

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Hi

I m using AT89C51/AT89S51 to drive the motor

the circuit is like controller generates the PWM on two pins( 50% duty cycle + equal and opposite)
that is fed into a latch and in turn latch drives the transistor + relay circuit

The relay in the response runs the motor in CW/ACW direction depending on PWM signal

my problem is that some times the program collapse and the controller does not accept and interrupt or input and starts rotating motor in single direction at very high speed. At that point the only way out is the complete shut down of circuit nothing else works

It is more likely to happen with 89c51 and less with 89s51

what cud be the possible reason

the program i wrote is


#include<reg51.h>
#include<stdio.h>


sbit out1=P2^0;
sbit out2=P2^1;


sbit sel1=P2^6;
sbit sel2=P2^7;


void main()


{

unsigned int count,initial;
P0=0;
P1=0;
P2=0;
P3=0;
//p0=0,p1=0;

for(initial=0;initial<100;initial++)
{
out2=0;
out1=0;

}


while(1)

{

if((sel1==1) && (sel2==0))
{
//sel1=0;

for(count=0;count<6500;count++)
{
out2=1;
out1=0;

}


for(count=0;count<50;count++)
{
out2=0;
out1=0;

}
for(count=0;count<6500;count++)
{
out2=0;
out1=1;

}

}

else if((sel1==0) && (sel2==1))

{

//sel2=0;
for(count=0;count<13500;count++)
{
out2=1;
out1=0;

}


for(count=0;count<500;count++)
{
out2=0;
out1=0;

}
for(count=0;count<13500;count++)
{
out2=0;
out1=1;

}

for(count=0;count<500;count++)
{
out2=0;
out1=0;

}

}


else if (((sel1==0) && (sel2==0)) ||((sel1==1) && (sel2==1)))
{

out1=0;
out2=0;
}




}

}


plz point out any mistake in the program . Plz also note that this problem occur when i connect the load on the circuit other wise it runs fine on no load
 

Please post the circuit, it might be a hardware problem.
 

here is the circuit diagram

i hope now i can know where i m mistaken

uzmeed

 

Your image is too small and not clearly visible, you have to attach a bigger one

Alex
 

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