ADC help

Can someone tell me why this code doesnt do its job? I am new to uVision. The code should turn on the LED diodes as you turn the potentiometer. For example, if its on position 0V the first LED should be lit, and if its on position 3.3V the last one. Tnx in advance

#include <stdio.h>
#include <stdlib.h>
#include <LPC214x.h>

void delay(int i){
unsigned int j;
for(j=0; j < i; j++);
}

int main (void) {
unsigned int rez;
IODIR1 = 0x00FF0000; //diode postavljene kao output
AD0CR = 0x00200402; //ADC1: 10-bit AIN1 @ 3MHz

while(1){ AD0CR |= 0x01000000; // start AD konverzije

while ((AD0DR1 & 0x80000000) == 0); // cekanje da se konverzija zavrsi

AD0CR &= ~0x01000000; //stop AD konverzije rez = AD0DR1 & 0x0000FFC0; if(rez < 128) IOSET1 = 1 << 16; else if(rez > 128 && rez < 256) IOSET1 = 1 << 17; else if(rez > 256 && rez < 256+128) IOSET1 = 1 << 18; else if(rez > 256+128 && rez < 512) IOSET1 = 1 << 18; else if(rez > 512 && rez < 512+128) IOSET1 = 1 << 19; else if(rez > 512+128 && rez < 768) IOSET1 = 1 << 20; else if(rez > 768 && rez < 768+128) IOSET1 = 1 << 21; else if(rez > 896 && rez < 1024) IOSET1 = 1 << 22; else IOSET1 = 1 << 23;

delay(100000);
}

}