adc.c

利用avr的芯片MEGA64L的ADC功能来计算电压

#include<mega64.h>     
#define VREF   3.3 
#define UDRE0   5        
#define ADIF    4
#define ADEN    7
volatile unsigned char n;
volatile unsigned int alt2;
volatile unsigned int vcc2;
                     
void initadc(void)
{
ADMUX=0X40;
ADCSRA=0X86;
} 
void initusart0(void)          //串口0的初始化
{
  UCSR0C =0x06;
  UBRR0L=0x07; 
  UBRR0H=0x00;
  UCSR0A = 0x00;
  UCSR0B = 0x98;
} 
 void put_c(char c)
   {
   while(!(UCSR0A&(1<<UDRE0)));
   UDR0=c;
   }  
  
unsigned int read_adc(unsigned char abc_input)
  { 

   ADMUX=abc_input;
   ADCSRA=0Xc6;
   while((ADCSRA&0X10)==0);
   ADCSRA&=~(1<<ADIF); 
   ADCSRA&=~(1<<ADEN);
   return ADCW;
   }

void inittime0(void)
{
   TIMSK=0X10;
   ETIMSK=0X00;
   TCCR1A=0X00;
   TCCR1B=0X0C;
   TCCR1C=0X00;  
   OCR1A=28800;
   } 
    unsigned int alt_on(void)
  {
        unsigned int alt;
        unsigned int alt1;
        alt1=(read_adc(0x40))*100;
        alt=alt1*VREF/1024;
        return alt;
  }
  unsigned int vcc_on(void)
{      
  unsigned int vcc1;
  unsigned int vcc;
  vcc1=(read_adc(0x41))*100;     
  vcc=vcc1*VREF/1024;       
  return vcc;
} 
void inttostr_adc(unsigned int vcc)
{
 unsigned int z;
 unsigned int u;
 unsigned int q;
 z=vcc/100+0x30;
 u=vcc%100/10+0x30;
 q=vcc%10+0x30;
 put_c(z);
 put_c(u);
 put_c(q);
 put_c(0x0d);
 put_c(0x0a);
}
  
   interrupt[TIM1_COMPA]void timer1_compa(void)
   {
     n++;
     if(n==5){
     alt2=alt_on() ; 
     inttostr_adc(alt2);
     vcc2=vcc_on(); 
     inttostr_adc(vcc2);
     n=0;  

     }
}
void main(void)
{  
 #asm("sei")
 inittime0();
 initadc();      
 initusart0(); 
 PORTA=0xFF;											
 PORTC=0xFF;
 DDRB=0x60;				
 PORTB=0x40;				
 DDRD=0x01;
 PORTD=0x01;								
 
 DDRE=0x20;
}