Tóm tắt : Qua bài này các bạn có thể sử dụng được ADC của AVR
Giới thiệu :
Phần cứng các bạn cần 1 con biến trở nối vào portA.0
Mạch ATmega16 như bài đầu .
Các chế độ sẽ chọn :
sử dụng chế độ ngắt ADC, tự động scan giá trị analog của port A
Ví dụ : Dùng PORTA.0 nhận giá trị từ biến trở hiển thị lên LCD theo ADC 8bit (từ 0->5V thành 0 ->255)
Chú ý :
trong chương trình có sử dụng hàm lcd_putnum(value); hiển thị chữ số
/*****************************************************
This program was produced by the
CodeWizardAVR V1.24.8d Professional
Automatic Program Generator
© Copyright 1998-2006 Pavel Haiduc, HP InfoTech s.r.l.
http://www.hpinfotech.com
Project :
Version :
Date : 1/9/2008
Author : LENGOCTUAN
Company : VAGAM
Comments:
Comments:
Chip type : ATmega16
Program type : Application
Clock frequency : 8.000000 MHz
Memory model : Small
External SRAM size : 0
Data Stack size : 256
*****************************************************/
#include
// Alphanumeric LCD Module functions
#asm
.equ __lcd_port=0x15 ;PORTC
#endasm
#include
#define FIRST_ADC_INPUT 0
#define LAST_ADC_INPUT 7
unsigned char adc_data[LAST_ADC_INPUT-FIRST_ADC_INPUT+1];
#define ADC_VREF_TYPE 0x20
// ADC interrupt service routine
// with auto input scanning
interrupt [ADC_INT] void adc_isr(void)
{
register static unsigned char input_index=0;
// Read the 8 most significant bits
// of the AD conversion result
adc_data[input_index]=ADCH;
// Select next ADC input
if (++input_index > (LAST_ADC_INPUT-FIRST_ADC_INPUT))
input_index=0;
ADMUX=(FIRST_ADC_INPUT|ADC_VREF_TYPE)+input_index;
// Start the AD conversion
ADCSRA|=0x40;
}
// Declare your global variables here
void lcd_putnum(unsigned int d)
{
unsigned char donvi, chuc, tram;
donvi=d%10;
d=d/10;
chuc=d%10;
d=d/10;
tram=d%10;
d=d/10;
if(tram>0)
{
lcd_putchar(48+tram);
lcd_putchar(48+chuc);
lcd_putchar(48+donvi);
}
else if(chuc>0)
{
lcd_putchar(48+chuc);
lcd_putchar(48+donvi);
lcd_putsf(" ");
}
else {
lcd_putchar(48+donvi);
lcd_putsf(" ");
lcd_putsf(" ");
}
}
void main(void)
{
// Declare your local variables here
// Input/Output Ports initialization
// Port A initialization
// Func7=In Func6=In Func5=In Func4=In Func3=In Func2=In Func1=In Func0=In
// State7=T State6=T State5=T State4=T State3=T State2=T State1=T State0=T
PORTA=0x00;
DDRA=0x00;
// Port B initialization
// Func7=In Func6=In Func5=In Func4=In Func3=In Func2=In Func1=In Func0=In
// State7=T State6=T State5=T State4=T State3=T State2=T State1=T State0=T
PORTB=0x00;
DDRB=0x00;
// Port C initialization
// Func7=In Func6=In Func5=In Func4=In Func3=In Func2=In Func1=In Func0=In
// State7=T State6=T State5=T State4=T State3=T State2=T State1=T State0=T
PORTC=0x00;
DDRC=0x00;
// Port D initialization
// Func7=In Func6=In Func5=In Func4=In Func3=In Func2=In Func1=In Func0=In
// State7=T State6=T State5=T State4=T State3=T State2=T State1=T State0=T
PORTD=0x00;
DDRD=0x00;
// Timer/Counter 0 initialization
// Clock source: System Clock
// Clock value: Timer 0 Stopped
// Mode: Normal top=FFh
// OC0 output: Disconnected
TCCR0=0x00;
TCNT0=0x00;
OCR0=0x00;
// Timer/Counter 1 initialization
// Clock source: System Clock
// Clock value: Timer 1 Stopped
// Mode: Normal top=FFFFh
// OC1A output: Discon.
// OC1B output: Discon.
// Noise Canceler: Off
// Input Capture on Falling Edge
// Timer 1 Overflow Interrupt: Off
// Input Capture Interrupt: Off
// Compare A Match Interrupt: Off
// Compare B Match Interrupt: Off
TCCR1A=0x00;
TCCR1B=0x00;
TCNT1H=0x00;
TCNT1L=0x00;
ICR1H=0x00;
ICR1L=0x00;
OCR1AH=0x00;
OCR1AL=0x00;
OCR1BH=0x00;
OCR1BL=0x00;
// Timer/Counter 2 initialization
// Clock source: System Clock
// Clock value: Timer 2 Stopped
// Mode: Normal top=FFh
// OC2 output: Disconnected
ASSR=0x00;
TCCR2=0x00;
TCNT2=0x00;
OCR2=0x00;
// External Interrupt(s) initialization
// INT0: Off
// INT1: Off
// INT2: Off
MCUCR=0x00;
MCUCSR=0x00;
// Timer(s)/Counter(s) Interrupt(s) initialization
TIMSK=0x00;
// Analog Comparator initialization
// Analog Comparator: Off
// Analog Comparator Input Capture by Timer/Counter 1: Off
ACSR=0x80;
SFIOR=0x00;
// ADC initialization
// ADC Clock frequency: 1000.000 kHz
// ADC Voltage Reference: AREF pin
// ADC Auto Trigger Source: None
// Only the 8 most significant bits of
// the AD conversion result are used
ADMUX=FIRST_ADC_INPUT|ADC_VREF_TYPE;
ADCSRA=0xCB;
// LCD module initialization
lcd_init(16);
// Global enable interrupts
#asm("sei")
lcd_gotoxy(0,0);
lcd_putsf("ADC");
while (1)
{
// Place your code here
lcd_gotoxy(4,1);
lcd_putnum(adc_data[0]);
};
}
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