program for Elevator Interface in 8051

#include <REG51F.H>

void delay(unsigned int);

main()

{

unsigned char Flr[9] = {0xff,0x00,0x03,0xff,0x06,0xff,0xff,0xff,0x09};

unsigned char FClr[9] = {0xff,0x0E0,0x0D3,0xff,0x0B6,0xff,0xff,0xff,0x79};

unsigned char ReqFlr,CurFlr = 0x01,i,j;

P0 = 0x00;

P0 = 0x0f0;

while(1)

{

P1 = 0x0f;

ReqFlr = P1 | 0x0f0;

while(ReqFlr == 0x0ff)

ReqFlr = P1 | 0x0f0; /* Read Request Floor from P1 */

ReqFlr = ~ReqFlr;

if(CurFlr == ReqFlr) /* If Request floor is equal to Current Floor */

{

P0 = FClr[CurFlr]; /* Clear Floor Indicator */

continue; /* Go up to read again */

}

else if(CurFlr > ReqFlr) /* If Current floor is > request floor */

{

i = Flr[CurFlr] - Flr[ReqFlr]; /* Get the no of floors to travel */

j = Flr[CurFlr];

for(;i>0;i--) /* Move the indicator down */

{

P0 = 0x0f0|j;

j--;

delay(25000);

}

}

else /* If Current floor is < request floor */

{

i = Flr[ReqFlr] - Flr[CurFlr]; /* Get the no of floors to travel */

j = Flr[CurFlr];

for(;i>0;i--) /* Move the indicator Up */

{

P0 = 0x0f0 | j;

j++;

delay(25000);

}

}

CurFlr = ReqFlr; /* Update Current floor */

P0 = FClr[CurFlr]; /* Clear the indicator */

}

}

void delay(unsigned int x)

{

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

}