[preethi]

The input which is to be converted to digital form can be selected by using three address lines using three address lines. So, that you can connect three sensors at a time..

the code is as follows… but you have to write the logics of 3 sensors which you are using….i have left space for that ..and also once check the ports that you are using for adc, lcd connection as per your circuit diagram..i have declared roughly..

 

#include<reg51.h>

sbit ale=P1^0;       // Address latch enable

sbit oe=P1^3;        // Output enable

sbit sc=P1^1;            // Start conversion

sbit eoc=P1^2;          // End of conversion

sbit clk=P1^7;           // Clock

sbit ADD_A=P1^4;      //Address pins for selecting input channels.

sbit ADD_B=P1^5;

sbit ADD_C=P1^6;

sfr lcd_data_pin=0xA0;  //Port P2

sbit rs=P3^0;

sbit rw=P3^1;

sbit en=P3^6;

sfr input_port=0x80;  //Port P0

 

void timer0  interrupt 1 ( )  // Function to generate clock of frequency 500KHZ using Timer 0 interrupt.

{

clk=~clk;

}

 

void delay(unsigned int count)  // Function to provide time delay in msec.

{

int i,j;

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

  for(j=0;j<1275;j++);

}

 

void lcd_command(unsigned char comm)  //Function to send command to LCD.

{

lcd_data_pin=comm;

en=1;

rs=0;

rw=0;

delay(1);

en=0;

}

           

void lcd_data(unsigned char disp)         //Function to send data to LCD.

{

lcd_data_pin=disp;

en=1;

rs=1;

rw=0;

delay(1);

en=0;

}

 

lcd_data(unsigned char *disp)             //Function to send string data to LCD.

{

int x;

for(x=0;disp[x]!=0;x++)

{

  lcd_data(disp[x]);

}

}

 

here you declare the function of your 3 sensors logic seperatly

 

void lcd_ini()                        //Function to inisialize the LCD

{

lcd_command(0x38);                                 // for using 8-bit 2 row LCD

delay(5);

lcd_command(0x0F);                                 // for display on cursor blinking

delay(5);

lcd_command(0x80);

delay(5);                                                              //Force cursor to blink at line 1 positon 0

}

 

 

void adc( )                                           //Function to drive ADC

{

while(1)

  {

   if(temp1==0)

   {

    ADD_C=0;                                               // Selecting input channel 1 using address lines

    ADD_B=0;

    ADD_A=0;

   }

   if(temp1==1)

   {

    ADD_C=0;  // Selecting input channel 2 using address lines

    ADD_B=0;

    ADD_A=1;

   }

   if(temp1==2)

   {

    ADD_C=0;                    // Selecting input channel 3 using address lines

    ADD_B=1;

    ADD_A=0;

   }

   delay(2);

   ale=1;

   delay(2);

   sc=1;

   delay(1);

   ale=0;

   delay(1);

   sc=0;

   while(eoc==1);

   while(eoc==0);

   oe=1;

   BCD();

   delay(2);

   oe=0;

   temp1++;

   if(temp1=)

   temp1=0;

  }

}

 

void main( )

{

  eoc=1;

    ale=0;

   oe=0;

   sc=0;

  TMOD=0x02;                     //Timer0 setting for generating clock of 500KHz using interrupt enable mode.

  TH0=0xFD;

  IE=0x82;

  TR0=1;

  temp1=0;

key1=0;

lcd_ini();

 

 

 

 

here you add your desired sensor call statement

 

 

 

 

 

   adc( );

}

[preethi]

hi bob……..in your circuit you have connected adc0804 data pins to microcontroller port1 that means p1.0 to p1.7….But in your program you have given it to microcontroller port2 that means p2

and also

As per your circuit you have connected rd, wr, cs, intr pins of adc0804 to port 3……. but in the program it is declared as port1

So, make changes in  your code for adc0804 to connect data pins of adc0804 to port1 and control pins rd, wr, cs, intr to port3 of microcontroller

correct lines as per your circuit  are 

 

               rd equ P3.0 ;Read signal P3.0

               wr equ P3.1 ;Write signal P3.1

               cs equ P3.2 ;Chip Select P3.2

               intr equ P3.3 ;INTR signal P3.3

 

               adc_port equ P1 ;ADC data pins P1

[preethi]

use keil micro vision software to convert c code to hexa file

 

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