DHT11温湿度测量电路图及程序

#include

#define uint unsigned int

#define uchar unsigned char

sbit io=P1^0;//DHT11数据端

sbit wela=P2^7;// 数码管位选

sbit dula=P2^6;//数码管段选

uchar data_byte;

uchar RH,RL,TH,TL;

uchar table[]={0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x98}; uchar wei[]={0x01,0x02,0x04,0x08,0x10,0x20,0x40,0x80};

void delay(uchar z)

{

uchar x,y;

for(x=z;x>0;x--)

for(y=110;y>0;y--);

}

void delay1() //延时10us

{

uchar i;

i--;

i--;

i--;

i--;

i--;

i--;

}

void start()//开始信号

{

io=1;

delay1();

io=0;

delay(20);//>18ms

io=1;

delay1();//20-40us

delay1();

delay1();

delay1();

delay1();

}

uchar receive_byte()

{

uchar i,temp,count;

for(i=0;i<8;i++)

{

count=2;

while((!io)&&count++)//等待50us低电平结束

temp=0;

delay1();delay1();delay1();delay1();

if(io==1)temp=1;

count=2;

while((io)&&count++);

if(count==1)break;

data_byte<<=1;

data_byte|=temp;

}

return data_byte;

}

void receive()

{

uchar T_H,T_L,R_H,R_L,check,num_check;

uchar count;

start();//开始信号

io=1;

if(!io)//读取DHT11响应信号

{

count=2;

while((!io)&&count++);//DHT11高电平80us是否结束

count=2;

while((io)&&count++);

R_H=receive_byte();

R_L=receive_byte();

T_H=receive_byte();

T_L=receive_byte();

check=receive_byte();

io=0;//拉低延时50us

delay1();delay1();delay1();delay1();delay1();

io=1;

num_check=R_H+R_L+T_H+T_L;

if(num_check=check)

{

RH=R_H;

RL=R_L;

TH=T_H;

TL=T_L;

check=num_check;

}

}

}

void display(uchar i,uchar j)//数码管显示{

P0=wei[i];

wela=1;

wela=0;

P0=0xff;

P0=table[j/10];

dula=1;

dula=0;

delay(1);

P0=0xff;

P0=wei[i+1];

wela=1;

wela=0;

P0=0xff;

P0=table[j%10];

dula=1;

dula=0;

delay(1);

}

void main()

{

while(1)

{

receive();

display(0,RH);

delay(1);

display(2,TH);

delay(1);

// display(4,TH);

// delay(1);

// display(6,TL);

// delay(1);

}

}