Interfacing Analog-to-Digital Converter with 8051 microcontroller

Introduction:

ADC0804 is one of the most commonly used analog to digital converter IC. In many applications it is required to convert the output of the sensor, which is analogue in nature to a digital form. The data in digital format can then be utilized for further processing by the digital processors. Typical applications include sound processing, temperature processing etc. The below figure demonstrates the principle and operation of interfacing a simple ADC 0804 using 8051 microcontroller.

(courtesy: Engineergargae.com)

Program:  

#include "REGX52.H" 

#define Mydata P2 
#define LED P0 
#define INTR P1_3 
#define WR P1_1 
#define RD P1_0 

void main() 

 { 
  unsigned char value; 
  Mydata=0xFF; //make P1 as input 
  INTR=1; RD=1; WR=1; 
   while(1) 
    { 
     WR=0; //send WR pulse 
     WR=1; //L to H (start conversion) 
     while(INTR==1); //wait for End of Conversion 
     RD=0; //send RD pulse 
     value=Mydata; //read value 
     LED=value; //display on 8-LEDs 
    } 
  }

Explanation:

There are 3 different values are used INTR(interrupt), RD(read), WR(write). Whereas, Mydata takes the input ADCo8o4 converts the data taken from the microcontroller and converted to digital values in the ouput connected to the LEDs. When WR=1 the conversion takes place until the RD=0  has been sent.