关于在MINI板上运行DHT11 出现的错误不解运行的时候读取的温湿度始终是24

wangwww2014_1_1 · 发表于 2014-1-17 13:08:30

DHT11电源接的3V现在运行的时候读取的温湿度始终是24
我是用的PC0

//??DHT11
void DHT11_Rst(void)
{
/**/
DHT11_IO_OUT(); //SET OUTPUT
DHT11_DQ_OUT=0; //??DQ
delay_ms(18);    //????18ms
DHT11_DQ_OUT=1; //DQ=1
delay_us(40);     //????20~40us
}
//??DHT11???
//??1:????DHT11???
//??0:??
u8 DHT11_Check(void)
{
u8 retry=0;

DHT11_IO_IN();//SET INPUT
while (DHT11_DQ_IN&&retry<100)//DHT11???40~80us
{
  retry++;
  delay_us(100);
};
printf("1 RETRY %d\r\n",retry);
if(retry>=100){printf("1 CHECK FAILED %d\r\n",retry);return 1;}
else retry=0;
while (!DHT11_DQ_IN&&retry<100)//DHT11????????40~80us
{
  retry++;
  delay_us(1);
};
if(retry>=100){printf("2 CHECK FAILED %d\r\n",retry);return 1;}
return 0;
}
//?DHT11?????
//???:1/0
u8 DHT11_Read_Bit(void)
{
  u8 retry=0;
while(DHT11_DQ_IN&&retry<100)//???????
{
  retry++;
  delay_us(1);
}
retry=0;
while(!DHT11_DQ_IN&&retry<100)//??????
{
  retry++;
  delay_us(1);
}
delay_us(40);//??40us
if(DHT11_DQ_IN)return 1;
else return 0;
}
//?DHT11??????
//???:?????
u8 DHT11_Read_Byte(void)
{
    u8 i,dat;
    dat=0;
for (i=0;i<8;i++)
{
     dat<<=1;
     dat|=DHT11_Read_Bit();
    }
    return dat;
}
//?DHT11??????
//temp:???(??:0~50°)
//humi:???(??:20%~90%)
//???:0,??;1,????
u8 DHT11_Read_Data(u8 *temp,u8 *humi)
{
  u8 buf[5];
u8 i;
DHT11_Rst();
if(DHT11_Check()==0)
{printf("Read DHT11\r\n");
  for(i=0;i<5;i++)//??40???
  {
   buf=DHT11_Read_Byte();
  }
  if((buf[0]+buf[1]+buf[2]+buf[3])==buf[4])
  {
   *humi=buf[0];
   *temp=buf[2];
  }
}else return 1;
return 0;
}
//???DHT11?IO? DQ ????DHT11???
//??1:???
//??0:??
u8 DHT11_Init(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC, ENABLE); //??PG????

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;     //PG11????
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;    //????
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_Init(GPIOC, &GPIO_InitStructure);     //???IO?
  GPIO_SetBits(GPIOC,GPIO_Pin_0);       //PG11 ???

DHT11_Rst(); //??DHT11
return DHT11_Check();//??DHT11???
}

-------------------

//IO
#define DHT11_IO_IN() {GPIOC->CRL&=0XFFFFFFF0;GPIOC->CRL|=8<<0;}
#define DHT11_IO_OUT() {GPIOC->CRL&=0XFFFFFFF0;GPIOC->CRL|=3<<0;}
////IO??×÷????
#define DHT11_DQ_OUT PCout(0) //PCn
#define DHT11_DQ_IN PCin(0) // Cn


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在DHT11_Check()函数里总是在第一个WHILE里出错，如果通过CHECK计数变量总为0