#include <LPC17xx.h>

#define RS_CTRL 0x08000000
#define EN_CTRL 0x10000000
#define DT_CTRL 0x07800000

unsigned long int temp1 = 0, temp2 = 0, i, j;
unsigned char flag1 = 0, flag2 = 0;
unsigned long result, y; // ADC result

void lcd_write(void);
void port_write(void);
void delay_lcd(unsigned long);

unsigned long int init_command[] = {0x30, 0x30, 0x30, 0x20, 0x28, 0x0C, 0x01, 0x80};

void ADC_Init(void) {
    LPC_PINCON->PINSEL3 = 3 << 28;
    LPC_SC->PCONP = 1 << 12;
    LPC_ADC->ADCR = 1 << 4 | 1 << 16 | 1 << 21;
    LPC_ADC->ADINTEN = (1 << 4);
    NVIC_EnableIRQ(ADC_IRQn);
}

void ADC_IRQHandler(void) {
    result = (LPC_ADC->ADGDR & (0xFFF << 4)) >> 4;
    y = (LPC_ADC->ADDR4 & (0xFFF << 4)) >> 4;
}

int main() {
    LPC_GPIO0->FIODIR = DT_CTRL | RS_CTRL | EN_CTRL;
    ADC_Init();

    flag1 = 0;
    for (i = 0; i < 8; i++) {
        temp1 = init_command[i];
        lcd_write();
    }

    flag1 = 1;
    delay_lcd(500000);

    // Convert result to 4 ASCII digits
    unsigned char digits[4];
    digits[0] = (result / 1000) % 10 + '0';
    digits[1] = (result / 100) % 10 + '0';
    digits[2] = (result / 10) % 10 + '0';
    digits[3] = result % 10 + '0';

    for (i = 0; i < 4; i++) {
        temp1 = digits[i];
        lcd_write();
    }

    while (1);
}

void lcd_write(void) {
    flag2 = (flag1 == 1) ? 0 : (((temp1 == 0x30) || (temp1 == 0x20)) ? 1 : 0);
    temp2 = temp1 & 0xf0;
    temp2 = temp2 << 19;
    port_write();

    if (!flag2) {
        temp2 = temp1 & 0x0f;
        temp2 = temp2 << 23;
        port_write();
    }
}

void port_write(void) {
    LPC_GPIO0->FIOPIN = temp2;
    if (flag1 == 0) {
        LPC_GPIO0->FIOCLR = RS_CTRL;
    } else {
        LPC_GPIO0->FIOSET = RS_CTRL;
    }
    LPC_GPIO0->FIOSET = EN_CTRL;
    delay_lcd(100);
    LPC_GPIO0->FIOCLR = EN_CTRL;
    delay_lcd(500000);
}

void delay_lcd(unsigned long r1) {
    unsigned long r;
    for (r = 0; r < r1; r++);
    return;
}