program for Stepper motor interface in 8051

#include <REG51xD2.H>

static bit Dir=0;

void delay(unsigned int x) /* Delay Routine */

{

for(;x>0;x--);

}

void ChangeDir(void) interrupt 0 /* Int Vector at 000BH, Reg Bank 1 */

{

Dir = ~Dir; /* Complement the Direction flag */

ClrLcd();

if(Dir)

delay(32000);

else

delay(32000);

}

main()

{

unsigned char Val,i;

EA=0x1; /* Enable Interrupt flag and Interrupt 0 & Serial Interrupt */

EX0=0x1;

ES=0x1;

P0=0x00; /*since the monitor is using the serial interrupt it has to be enabled*/

while(1)

{

if(Dir) /* If Dir Clockwise */

{

Val = 0x88;

for(i=0;i<4;i++)

{

P0 = Val; /* Write data for clock wise direction*/

Val = Val>>1;

delay(575);

}

}

else /* AntiClockwise Direction */

{

Val = 0x11;

for(i=0;i<4;i++)

{

P0 = Val; /* Write data for anticlock wise direction*/

Val = Val<<1;

delay(575);

}

}

}

}