explanation and pin configuration for code in lpc2148

#include<lpc214x.h> // Header file for Phillips LPC2148 controller
#include<stdio.h>
#define CCLK 30
#define PCLK 10
#include<uart.h>
#include<stdlib.h>
int x;
int y;
int xcoordinate(void);
int ycoordinate(void);

void delayms(unsigned int ms);
#define DAC_BIAS   0x00010000
int main(void)
{
        xcoordinate();

        ycoordinate();

}
void delayms(unsigned int ms)
{

        T0TCR = 0x02;
        T0TCR = 0x01;
        while( T0TC < ms);
        T0TCR = 0x00;
}
int xcoordinate(void)
{
 int x;
 PINSEL0 = (PINSEL0 & 0x3FFF3FF0) | 0x00000005; // Configure pins for touch screen
 PINSEL1 = (PINSEL1 & 0xC3FFFFFF) | 0x10000000;
 IO0DIR =  (IO0DIR &  0xDFFF7F7F) | 0x00008080;

 IO0SET = IO0SET | 0x00000080;     // Set pin to '1'
 IO0CLR = IO0CLR | 0x00008000;    // Set pin to '0'

 AD0CR = ( AD0CR & 0xFFD00000 ) | 0x00200208 ;  // Start the ADC

 while(1)
 {
   delayms(10);
   AD0CR = ( AD0CR & 0xF8FFFFFF ) | 0x01000000 ;

 xchkadc:

   x = AD0DR3 & 0x80000000 ;

   if(x == 0x80000000)  // Check if A-D conversion is complete
    {

      x = 0x00000000;
      x = AD0DR3 & 0x0000FFC0;
      x = x >> 6;
      x = x & 0x000003FF;
      if(x <= 10)
      {
        goto xexit;
      }

      AD0CR = AD0CR & 0xF8FFFFFF;
      return x;     // return the value of touch in x direction

    }

   goto xchkadc;

  xexit:
  AD0CR = AD0CR & 0xF8FFFFFF;
  }
  return 0;
}

int ycoordinate(void)
{
 int y;

 PINSEL0 = (PINSEL0 & 0x3FFF3FF0) | 0xC0000005;    // Configure pins for touch screen
 PINSEL1 = (PINSEL1 & 0xC3FFFFFF) | 0x00000000;

 IO0DIR = (IO0DIR & 0x9FFFFF7F) | 0x60000000;

 IO0SET = IO0SET | 0x40000000;    //// Set pin to '1'
 IO0CLR = IO0CLR | 0x20000000;    //// Set pin to '0'

 AD1CR = (AD1CR & 0xF0D00000) | 0x00200220 ;    //// Start the ADC

 while(1)
 {

  delayms(10);
  AD1CR = ( AD1CR & 0xF8FFFFFF ) | 0x01000000 ;

   ychkadc:

   y = AD1DR5 & 0x80000000 ;

   if(y == 0x80000000)    // Check if A-D conversion is complete
    {

      y = 0x00000000;
      y = AD1DR5 & 0x0000FFC0;
      y = y >> 6;
      y = y & 0x000003FF;
      if(y <= 10)
      {
        goto yexit1;
      }

      AD1CR = AD1CR & 0xF8FFFFFF;
      return y;            // return the value of touch in y direction

    }

   goto ychkadc;

   yexit1:

    AD1CR = AD1CR & 0xF8FFFFFF;
  }

 return 0;
}

this is a code for touch screen interface which I got from net...I don't understand which pins I should connect on my arm7 board to get the touch coordinates in lcd

Whats wrong with your reference manual?

The code you 'found' is very ugly. Maybe if you knew more about what you're after then you'd recognise something better.