ADC interfacing with 8081

Interfacing the AD0803 to the 8051 micro controller

      This is the parallel port connector to the micro controller. The adc reading is transmitted to the serial port.

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

#define     adc_port    P1

sbit     rd = P2^0;
sbit    wr = P2^1;
sbit    cs = P2^2;
sbit    intr = P2^3;

//unsigned int adc;
float adc1;

void serial_init()
{
    TMOD = 0x20;
    SCON = 0x50;
    TH1  = 0xFD;
    TR1  = 1;
    TI   = 1;
    RI   = 0;
     
}
                  
void delay(unsigned int i)
{
    unsigned int j,k;
    for(j=0;j<=i;j++)
    {
        for(k=0;k<256;k++);
    }
}

void adc_conv()
{
    cs = 0;
    wr = 0;
    wr = 1;
    cs = 1;
    while(intr);
}

void adc_read()
{
    cs = 0;
    rd = 0;
    adc1 = adc_port;
    delay(1);
    cs = 1;
    rd = 1;
}

void main()
{
    serial_init();
    printf("Hello World\n");
    delay(5);

    while(1)
    {
        adc_conv();
        //printf("Hello\n");
        adc_read();
        printf("   ADC = %.2f\n\r",adc1/51);
        delay(1);
    }
}


The Proteus image is attached