To write a C program Convert a particular analog input to its corresponding digital data using ADC

 

Aim:

To write a C program Convert a particular analog input to its corresponding digital

data using ADC.

Algorithm :

Step1. Declare control word register at address 0xe003

Step 2. Initialize Port A, Port B & Port C with memory locations 0xe000, 0xe001 and 0xe003

respectively

Step 3. Set the SCON and TMOD for setting baud rate and timer mode

Step 4. Configure control word to 0x92 for setting port a and port b as input and port c as

output ports

Step 5. Convert the input value to digital value

Step 6. Conversion value was viewed by using UART

Step 7. Once conversion is completed Check whether the key entered is '0x2c'

Step 8. If the key is 0x2c display the next channel result in UART

Step 9. Stop the execution

Program

#include <REG51xD2.H>

#include <stdio.h>

#include <intrins.h>

unsigned char xdata porta _at_ 0xe000;

unsigned char xdata portb _at_ 0xe001;

unsigned char xdata portc _at_ 0xe002;

unsigned char xdata ctrl _at_ 0xe003;

unsigned char xdata result[3] _at_ 0x9000;         //to store the channel no. and the digital value

void delay();

void again();

void convert()

{

unsigned char temp = 0x00;

temp = result[0];

temp <<= 2;

temp |= 0x23;

portc = temp;

delay();

again();

}

void delay()

{

unsigned char ch = 0;

for(ch = 0; ch <= 0x10; ch ++) ;

}

void again()

{

ctrl = 0x02;

_nop_();

ctrl = 0x03;

_nop_();

_nop_();

_nop_();

_nop_();

ctrl = 0x00;                        //send PC0 low to start the conversion

result[1] = porta;            //Read the LSB of the digital value from porta

result[2] = portb;            //Read the MSB of the digital value from portb

printf("\nChannel : ")    //Print the channel value

SBUF = (result[0]+0x30);

_nop_();

printf("\nDigital Value = 0x0%x%x",result[2],result[1]);    //Print the digital value

putchar(0x8)

 putchar(0x20);

}

void main()

{

unsigned char input = 0x00;

SCON = 0x52;                                                                        //Initialize UART of 8051

TMOD |= 0x20;

TH1 = 0xe6;

TR1 = 1;

result[0] = 0x00;

ctrl = 0x92;                                                                            //Configure porta and portb as input and portc

as output ports

portc = 0x03;                                                                      //Latch is edge triggeres

convert();

while(1)

{

input = getchar();                                                            //Get the input from the PC keyboard

if(input == 0x2c)                                                             //Check whether the key entered is ',' or '-' or '-'

{

result[0] += 1;

result[0] &= 0x07;

convert();

}

}

}