ADC and LCD interfacing issue

For some reason, people seems to forget that it sometimes helps to perform a preprocessor expansion and look at what the "real" code actually looks like. That will quickly explain why the compiler is unhappy...

For some reason, people seems to forget

I'm regrettably sure it's worse than that. To be in a position to forget something, you have to know it first. The people we're dealing with here, never did.

This particular preprocessor mystery is a classic beginner's mistake; one which everyone has committed at least once in their career as a C programmer. The difference is in how you deal with it, and how often, until the lesson is fully learned: C compilers like their semicolons in exactly the right places, period.

oh! that was big shot. thanks for help. Still I am unable to understand bit handling.
for expression -
RD = 1;
I get an error - " syntax error near '=' "
I didn't get what does it mean?

I didn't get what does it mean?
It means you may have thanked us for the help, but you didn't actually follow it.

So post the current failing code, using PRE tags so the formatting is clear.

#include <reg51.h>
#include <stdio.h>
#include <string.h>
void msdelay(unsigned int time);
void convert_display(unsigned char value);

int INTR;
#define RD = P2^5
#define WR = P2^6;
unsigned long MYDATA;

void main()
{ unsigned char value; RD = 1; WR = 1; INTR = P2^7; INTR = 1; MYDATA = P1; MYDATA = 0xFF; while(1) { WR=0; WR=1; while(INTR==1) { } RD=0; value=MYDATA; convert_display(value); RD=1; }
}

void convert_display(unsigned char value)
{ unsigned char x,d1,d2,d3; x=value/10; d1=value%10; d2=value/10; d3=x/10; P0=d1; msdelay(250); P0=d2; msdelay(250); P0=d3; msdelay(250);
}

void msdelay(unsigned int time)
{ unsigned char x,y; for(x=0;x<=time;x++) for(y=0;y<=1275;y++);
}

Error is displayed at line 15,16,23,27,30. Error - "syntax error near '=' ".
At every line I pass some int value to WR,RD, error is displayed.

The preprocessor is an _almost_ totally stupid search-and-replace function.

You have

#define RD P2^5;

So where you use RD, the preprocesor removes RD and inserts "P2^5;". How fun is that in your expression:

RD = 1;

where you end up with

P2^5; = 1;

Does the above look like valid C code? How many ';' does it take for a single C statement?

#include <reg51.h>
#include <stdio.h>
#include <string.h>
void msdelay(unsigned int time);
void convert_display(unsigned char value);

int INTR;
#define RD = P2^5
#define WR = P2^6
unsigned long MYDATA;

void main()
{ unsigned char value; RD = 1; WR = 1; INTR = P2^7; INTR = 1; MYDATA = P1; MYDATA = 0xFF; while(1) { WR=0; WR=1; while(INTR==1) { } RD=0; value=MYDATA; convert_display(value); RD=1; }
}

void convert_display(unsigned char value)
{ unsigned char x,d1,d2,d3; x=value/10; d1=value%10; d2=value/10; d3=x/10; P0=d1; msdelay(250); P0=d2; msdelay(250); P0=d3; msdelay(250);
}

void msdelay(unsigned int time)
{ unsigned char x,y; for(x=0;x<=time;x++) for(y=0;y<=1275;y++);
}

Error - syntax error near '='.
I think I'm making some mistake in passing value to RD,WR

P2^5; = 1;

Can be "translated to"

P2^5;
= 1;

First a meaningless pin read without any use of the result.

Then a very interesting expression where some magic "nothing" should be given the value 1.

I don't blame the compiler for not liking a statement starting with a '='.

Please will you give me c code? I'll study the code. - Take input from ADC 0804 and display it at 16x2 lcd display.