(ESL10) Analog to Digital Converter

Code

#include <stdio.h>
#include <LPC17xx.h>
#include "lcd.h"

#define REF_VTG 3.300
#define FULL_SCALE 0xFFF // 12 bit ADC

int main(void)
{
	unsigned int adc_temp;
	unsigned int i;
	float in_vtg;
	unsigned char vtg[7], dval[7], blank[] = "   ";
	unsigned char Msg3[11] = {"MIT:"};
	unsigned char Msg4[12] = {"Dept of IT:"};

	lcd_init();
	LPC_PINCON->PINSEL3 |= 0xC0000000; // P1.31 as AD0.5
	LPC_SC->PCONP |= (1 << 12);		   // enable the peripheral ADC

	temp1 = 0x80;
	lcd_com();
	delay_lcd(800);
	lcd_puts(&Msg3[0]);

	temp1 = 0xC0;
	lcd_com();
	delay_lcd(800);
	lcd_puts(&Msg4[0]);

	while (1)
	{
		LPC_ADC->ADCR = (1 << 5) | (1 << 21) | (1 << 24); // 0x01200001;
		//ADC0.5, start conversion and operational
		for (i = 0; i < 2000; i++)
			; // delay for conversion
		while ((adc_temp = LPC_ADC->ADGDR) == 0x80000000)
			; // wait till 'done' bit is 1, indicates conversion complete
		adc_temp = LPC_ADC->ADGDR;
		adc_temp >>= 4;
		adc_temp &= 0x00000FFF;												 // 12 bit ADC
		in_vtg = (((float)adc_temp * (float)REF_VTG)) / ((float)FULL_SCALE); // calculating input analog voltage
		sprintf(vtg, "%3.2fV", in_vtg);										 // convert the readings into string to display on LCD
		sprintf(dval, "%x", adc_temp);
		for (i = 0; i < 2000; i++)
			;

		temp1 = 0x8A;
		lcd_com();
		delay_lcd(800);
		lcd_puts(&vtg[0]);

		temp1 = 0xCB;
		lcd_com();
		lcd_puts(&blank[0]);

		temp1 = 0xCB;
		lcd_com();
		delay_lcd(800);
		lcd_puts(&dval[0]);

		for (i = 0; i < 200000; i++)
			;
		for (i = 0; i < 7; i++)
			vtg[i] = dval[i] = 0x00;
		adc_temp = 0;
		in_vtg = 0;
	}
}