sample1.c

来自「ATmega16上面的ADC测试」· C语言 代码 · 共 196 行

/*****************************************************
Date    : 2007-4-27
Author  : Laplace Zhang                            

Chip type           : ATmega16
Program type        : Application
Clock frequency     : 16.000000 MHz
Memory model        : Small
External SRAM size  : 0
Data Stack size     : 256
*****************************************************/

#include <mega16.h> 
#include <stdio.h>

// Alphanumeric LCD Module functions
#asm
   .equ __lcd_port=0x18
#endasm
#include <lcd.h>

#define ADC_VREF_TYPE 0x40  


void main_init(void);


// Read the AD conversion result
unsigned int read_adc(unsigned char adc_input)
{
        ADMUX=adc_input|ADC_VREF_TYPE;
        // Start the AD conversion
        ADCSRA|=0x40;
        // Wait for the AD conversion to complete
        while ((ADCSRA & 0x10)==0);
        ADCSRA|=0x10;
        return ADCW;
} 


void lcd_init_display()
{
	char line0[17]="Channel 1:0.000V";
	char line1[17]="Channel 2:0.000V";
	lcd_gotoxy(0,0);
	lcd_puts(line0);
	lcd_gotoxy(0,1);
	lcd_puts(line1);
}

void volt_display(unsigned int volt, unsigned char line)
{
	char str[6]="0.000";
	float f_volt;
	volt &= 0x3FF ;
	f_volt=((float)(volt*5))/0x400;
/////////////////////////////////////////////////
// 下面这句话是对结果的Gain Error的修正
// 但是这是人工的，暂时还没有弄懂自动修正的方法
// 不过自动修正也是通过软件来完成的。	         
// 结果用MATLAB拟合过。
	f_volt /= 1.2686;
	
	
	str[0]=((unsigned char)(f_volt))+48;
	str[2]=((unsigned char)(f_volt*10))%10+48;
	str[3]=((unsigned char)(f_volt*100))%10+48;
	str[4]=((unsigned char)(f_volt*1000))%10+48;
	lcd_gotoxy(10,line);
	lcd_puts(str);
}


// Declare your global variables here

void main(void)
{
	unsigned int volt0=0,volt1=0,tmp;
	main_init();
	lcd_init_display();
        
        while (1)
        {
        	tmp=read_adc(0);
        	if((volt0/0x4)!=(tmp/0x4))
        	{
        		volt0=tmp;
        		volt_display(volt0,0);
        	}
        	
        	tmp=read_adc(1);
        	if((volt1/0x4)!=(tmp/0x4))
        	{
        		volt1=tmp;
        		volt_display(volt1,1);
        	}
        }
}




void main_init(void)
{
        // Input/Output Ports initialization
        // Port A initialization
        // Func7=Out Func6=Out Func5=Out Func4=Out Func3=Out Func2=Out Func1=In Func0=In 
        // State7=0 State6=0 State5=0 State4=0 State3=0 State2=0 State1=T State0=T 
        PORTA=0x00;
        DDRA=0xFC;
        
        // Port B initialization
        // Func7=Out Func6=Out Func5=Out Func4=Out Func3=Out Func2=Out Func1=Out Func0=Out 
        // State7=0 State6=0 State5=0 State4=0 State3=0 State2=0 State1=0 State0=0 
        PORTB=0x00;
        DDRB=0xFF;
        
        // 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
        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
        // Analog Comparator Output: Off
        ACSR=0x80;
        SFIOR=0x00;
        
        // ADC initialization
        // ADC Clock frequency: 125.000 kHz
        // ADC Voltage Reference: AVCC pin
        // ADC High Speed Mode: Off
        // ADC Auto Trigger Source: Free Running
        ADMUX=ADC_VREF_TYPE;
        ADCSRA=0x87;
        SFIOR&=0x0F;
        
        // LCD module initialization
        lcd_init(16);
}