STC12C5A60S2的DHT22以及MQ-2的1602顯示程序

ID:86862 · 發表于 2018-5-11 22:41

這個程序是本人寫的，可在1602顯示，煙霧與溫濕度顯示程序。經測試，可用

單片機源程序如下:

#include"main.h"
sbit DHT22_DATA = P2^0;
unsigned char a,b,c,d,check=1; //8bit溫度整數數據+8bit溫度小數數據+8bit濕度整數數+8bit濕度小數數據+8bit校驗和
unsigned int R,T;
unsigned char n;
void delay500us(void) //誤差 -0.054253472222us
{
unsigned char a,b;
for(b=251;b>0;b--)
for(a=4;a>0;a--);
_nop_(); //if Keil,require use intrins.h
}
void delay20us(void) //誤差 -0.016637731481us
{
unsigned char a,b;
for(b=1;b>0;b--)
for(a=52;a>0;a--);
_nop_(); //if Keil,require use intrins.h
}
char Read_Byte()
{
char temp,tmp;
unsigned char i;
for(i=0;i<8;i++)
{
// delay20us();
n = 2;
while((!DHT22_DATA)&&n++); //等待50us間隔低電平響應結束
if(n == 1) return 0;
delay20us();delay20us(); //26-28us高電平為‘0’，70us高電平為‘1’
tmp = 0;
if(DHT22_DATA) tmp = 1;
n = 2;
while(DHT22_DATA&&n++); //若位為1,等待高電平結束
if(n == 1) return 0;
temp <<= 1;
temp |= tmp;
}
return temp;
}
unsigned char DHT22_Read()
{
DHT22_DATA = 0;
delay500us(); //拉低500us
DHT22_DATA = 1;
delay20us();delay20us(); //延時20-40us等待響應信號
DHT22_DATA = 1;
if(!DHT22_DATA)
{
n = 2;
while((!DHT22_DATA)&&n++); //等待80us低電平響應結束
if(n == 1) return 0;
delay20us();delay20us();delay20us();
n = 2;
while(DHT22_DATA&&n++); //等待80s高電平等待結束
if(n == 1) return 0;
a = Read_Byte();
b = Read_Byte();
c = Read_Byte();
d = Read_Byte();
check = Read_Byte();
DHT22_DATA = 1;
if(check != a+b+c+d) return 0;
}
R = a*256+b;
T = c*256+d;
return 1;
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