Pemrograman ADC AVR Atmega8535 dgn Resolusi 10 bit

ADC Atmega8535

Teori dasar ADC bisa baca disini

// Sensor di simulasikan oleh variable resistor di hubungkan ke pin ADC chanel 0 (kaki  40 atmega8535)

//Adc :  channel 0 (pin 40)

//Compiler:  CodeVision

//mengambil data ADC dengan interupt ADC.

// hasil konversi resolusi 10 bit , 00 0000 0000 ~ 11 1111 1111 (3FFH)

#include <mega8535.h>

#include <delay.h>

// Alphanumeric LCD Module functions

#asm

.equ __lcd_port=0×15 ;PORTC

#endasm

#include <lcd.h>

// ADC interrupt service routine

interrupt [ADC_INT] void adc_isr(void)

{

unsigned int polutan; //

// 20ms delay

delay_ms(20);

// Start a new AD conversion

ADCSRA|=0×40;

//data 10 bit hasil konversi disimpan di ADCW

polutan = (unsigned int) ADCW; //rubah  type data ADCW ke integer

if(polutan>500)

{ lcd_gotoxy(0,1);

lcd_putsf(“berbahaya “);

}

else

{

{ lcd_gotoxy(0,1);

lcd_putsf(“Tidak berbahaya”);

}

}

lcd_gotoxy(6,0);

lcd_putsf(“PPM”);

lcd_gotoxy(0,0);

//  rubah angka integer ke char Ascii , misal angka 1 ->  code ASCII =1 + 30 = 31H

lcd_putchar(polutan/1000 %10 + 0×30);   //menampilkan digit ribuan

lcd_putchar(polutan/100 %10 + 0×30);  //menampilkan digit ratusan

lcd_putchar(polutan/10 %10 + 0×30);  //menampilkan digit puluhan

lcd_putchar(polutan %10 + 0×30);  //menampilkan digit satuan

}

void main(void)

{

// ADC Interrupts: On

ADCSRA=0x8E;

// LCD module initialization

lcd_init(16);

lcd_gotoxy(6,0);

lcd_putsf(“PPM”);

// Global enable interrupts

#asm(“sei”)

// Select ADC input 0

ADMUX=0×40;

// Start the first AD conversion

ADCSRA|=0×40;

// All the job is done by ADC interrupts

while (1);

}

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