我的AVR资料[程序篇] 利用ADC通道0做的电压表(源码17)

正点原子 · 发表于 2010-12-22 00:50:16

这段代码利用ADC的通道0采集AD数据,参考电压为内部2.56V电压.然后将采集到的值取平均值,然后将该值转换为电压(mv),并显示在数码管上,以实现一个简单的电压表的功能.代码如下:
#include <mega16.h>
#include <delay.h>

#define ADC_VREF_TYPE 0xC0

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

void display(unsigned char number,unsigned char position)//digtial show function
{
    DDRB=0Xff;//set PORTA output
ORTB=0XFF;//set PORTA output in high level
    switch(position)//choice the position
{
  case 1:{PORTB&=0xf8;break;}
  case 2:{PORTB&=0xf9;break;}
  case 3:{PORTB&=0Xfa;break;}
  case 4:{PORTB&=0Xfb;break;}
  case 5:{PORTB&=0Xfc;break;}
  case 6:{PORTB&=0Xfd;break;}
  case 7:{PORTB&=0Xfe;break;}
  case 8:{PORTB&=0Xff;break;}
  }
    switch(number)//show number
{
  case 0:{PORTB&=0x87;break;}    //0
  case 1:{PORTB&=0x8f;break;}    //1
  case 2:{PORTB&=0x97;break;}    //2
  case 3:{PORTB&=0x9f;break;}    //3
  case 4:{PORTB&=0xa7;break;}    //4
     case 5:{PORTB&=0xaf;break;}    //5
  case 6:{PORTB&=0xb7;break;}    //6
  case 7:{PORTB&=0xbf;break;}    //7
  case 8:{PORTB&=0xc7;break;}    //8
     case 9:{PORTB&=0xcf;break;}    //9
  default:{PORTB=0xff;break;}    //null
}
}
//V messure
void main(void)
{
    unsigned char b1,b2,b3,b4,j;
unsigned int t;

    ADMUX=ADC_VREF_TYPE & 0xff;
    ADCSRA=0x83;//use inside ref 2.56V,1000KHz
while(1)
{
   b1=t%10;display(b1,8);delay_us(1000);
   b2=(t/10)%10;display(b2,7);delay_us(1000);
   b3=(t/100)%10;display(b3,6);delay_us(1000);
   b4=(t/1000)%10;display(b4,5)ORTB.7=0;
   j++;
   if(j>150)
   {
       j=0;t=0;
       for(j=0;j<20;j++)t+=read_adc(0);
       t=t/20;
       t=t*2.5;
       j=0;
   }
   else delay_us(1000);
   PORTB.7=1;
   }
}