基于单片机的数字电压表的设计c语言.doc
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#includereg52.h
#includeintrins.h
sbit st=P2^4;
sbit eoc=P3^7;
sbit oe=P2^5;
sbit ale=P2^3;
sbit key1=P3^6;
sbit key2=P3^5;
unsigned char
seg_code[]={0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90}; unsigned char seg_ale[]={0xf8,0xf9,0xfa,0xfb};
unsigned char num[4];
/************延时函数**********************/
void delay_us(unsigned int delayus)
{
while(delayus--);
}
void delay_ms(unsigned int delaytime)
{
unsigned int i;
unsigned char j;
for(i=0;idelaytime;i++)
for(j=0;j110;j++);
}
/********************************************/
/************ADC转换函数*********************/
void adc_convert(void)
{
double temp1;
unsigned int temp2,temp3;
st=0;
_nop_();
st=1;
_nop_();
st=0;
oe=0;
while(eoc==0);
oe=1;
_nop_();
temp1=P0;
_nop_();
temp1*=492; //基准电压 4.9 V
temp1/=255;
temp2=(unsigned int)temp1%1000;
num[2]=(unsigned char)(temp2/100);
temp3=(unsigned int)temp2%100;
num[1]=(unsigned char)(temp3/10);
num[0]=temp3%10;
delay_us(1);
oe=0;
}
/*******************************************/
/**************显示函数*********************/
void dis(void)
{
unsigned char i,b;
b=0x01;
for(i=0;i4;i++)
{
if(i==2)
P1=seg_code[num[i]]0x7f;
else if(i==3)
P1=seg_code[num[i]]0x7f;
else
P1=seg_code[num[i]]; P3=~b;
b=1;
delay_ms(5);
}
}
/*******************************************/
/****************主函数*********************/
void main(void)
{
unsigned char i,automatic;
unsigned char keynum;
int j;
for(i=0;i4;i++)
num[i]=0;
keynum=0;
for(;;)
{
/**************按键扫描******************************/
if(key1==0)
{
delay_ms(1);
dis();
delay_ms(1);
dis();
delay_ms(1);
dis();
delay_ms(1);
dis();
delay_ms(1);
dis();
delay_ms(1);
dis();
delay_ms(1);
dis();
if(key1==0)
{
if(keynum3)
keynum++;
else
keynum=0;
}
}
if(key2==0) //自动加按键
{
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