新手求助，关于DHT11，有经验的看一下

兜揣阳光

新手求助，关于DHT11，有经验的看一下 [复制链接]

最近在做MSP430F149驱动DHT11采集温湿度然后在LCD1602上显示的实验，但硬件连接好后总是显示00.0，好像DHT11没工作，看了好久找不出程序问题，希望有经验的你帮下忙，谢谢。。。原程序如下：

#include "msp430x14x.h" // 包含头文件
#define uchar unsigned char
#define uint unsigned int
#define DHT11_OUTPUT    P2DIR|=BIT0    
#define DHT11_INPUT     P2DIR&=~BIT0   
#define DHT11_H         P2OUT|=BIT0   
#define DHT11_L         P2OUT&=~BIT0  

#define DHT11_IN        (P2IN&BIT0)

uchar str1[]={"        "};
uchar str2[]={"        "};
uchar  dis1[] = {"TRH RH: "}; //定义数组
uchar  dis2[] = {"TRH  T: "};
uchar TH_data,TL_data,RH_data,RL_data,CK_data;
uchar TH_temp,TL_temp,RH_temp,RL_temp,CK_temp;
uchar com_data,untemp,temp;
uchar respond;

void Delayus(int n)
{
    CCR0 = n;
    TACTL |= (MC_1 + TACLR + TAIE);                 //增计数到CCR0,计数器清零,定时器A中断打开
    TACTL |= TACLR;
    TACTL |= MC_1;   
    while(!(TACTL & BIT0));                         //等待
    TACTL &= ~(MC_1 + TAIE + BIT0);                 //停止计数,关中断,清除中断标志
    TACTL &= ~MC_1;               //停止计数
    TACTL &= ~BIT0;              //清除中断标志
}

void delay(uint  z)
{
  uint t,y;
  for(t=z;t>0;t--)
  {
    for(y=110;y>0;y--);
  }
}

void write_com(uchar com)
{
  P3OUT&=~BIT0;//RS
  P3OUT&=~BIT1; //RW
  P5OUT=com;
  delay(5);
  P3OUT|=BIT2; //E
  delay(5);
  P3OUT&=~BIT2;
}

void write_data(uchar date)
{
  P3OUT|=BIT0;
  P3OUT&=~BIT1;
  P5OUT=date;
  delay(5);
  P3OUT|=BIT2;
  delay(5);
  P3OUT&=~BIT2;
}

void LCD_set_xy( uchar x, uchar y ) 
{
     uchar address;
     if (y == 0)
      address = 0x80 + x;
     else
         address = 0xc0 + x;
     write_com(address);
}

void LCD_write_char( uchar x,uchar y,uchar dat)
{
 LCD_set_xy( x, y );
 write_data(dat);
}

void init()
{
  P3DIR=0xff;
  P3SEL=0;
  P3OUT=0x00;
  P3OUT&=~BIT2;
  P3OUT&=~BIT0;
  P5DIR=0XFF;
  P5SEL=0;
  P5OUT=0X00;
  write_com(0x38);
  write_com(0x0c);
  write_com(0x06);
  write_com(0x01);
 
}

//设定LCD显示位置
void lcd_dis_pos(uchar pos)
{      
          write_com(pos | 0x80); //数据指针=80+地址变量
}

 

 

//收发信号检测，数据读取
char receive()
{   
          uchar i;

          com_data=0;
          for(i=0;i<=7;i++)   
         {
                    respond=2;
                    while((!DHT11_IN)&&respond++);
                    Delayus(40);
                   Delayus(40);
                
                    if(DHT11_IN)
                    {
                              temp=1;
                              respond=2;
                                while((DHT11_IN)&&respond++);
                    }
                    else
                              temp=0;
                    com_data<<=1;
                    com_data|=temp;   
          }
          return(com_data); 
}

 

//湿度读取子程序
//温度高8位== TL_data
//温度低8位== TH_data
//湿度高8位== RH_data
//湿度低8位== RH_data
//校验 8位 == CK_data
void read_TRH()
{        
          DHT11_OUTPUT;           //设置P2.0输出
          DHT11_H;                ////输出高
         Delayus(10);
         DHT11_L;
        Delayus(20000);
         DHT11_H;
          //DATA总线由上拉电阻拉高 主机延时20us
         Delayus(40);
         DHT11_INPUT;
         Delayus(60);
         Delayus(60);

          
          if(!(DHT11_IN))  
         {
                  respond=2;
                  //判断DHT11发出 80us 的低电平响应信号是否结束
                   while((!DHT11_IN)&&respond++);
                 respond=2;
                 //判断从机是否发出 80us 的高电平，如发出则进入数据接收状态
                while((DHT11_IN)&&respond++);
               //数据接收状态  
                RH_temp = receive();
                RL_temp = receive();
                TH_temp = receive();
                TL_temp = receive();
                CK_temp = receive();
                DHT11_OUTPUT;                       //设置P2.0输出
                DHT11_H;                            //P2.0输出高，释放总线
                 untemp=(RH_temp+RL_temp+TH_temp+TL_temp);
                 if(untemp==CK_temp)
                 {
                          RH_data = RH_temp;
                          RL_data = RL_temp;
                         TH_data = TH_temp;
                          TL_data = TL_temp;
                          CK_data = CK_temp;
                }
        }
                          // RH_data = 21;
                         // RL_data = 13;
                        // TH_data =36;
                         // TL_data = 40;
         //湿度整数部分
         str1[0] =(char)0X30+RH_data/10;
         str1[1] =(char) 0X30+RH_data%10;
         str1[2] =0x2e; //小数点
          //湿度小数部分
         str1[3] =(char) 0X30+RL_data/10;
          str1[5] = 0X25; //"%"
         str1[6] = 0X52; //"R"
         str1[7] = 0X48; //"H"
         //温度整数部分
         str2[0] =(char) 0X30+TH_data/10;
         str2[1] =(char) 0X30+TH_data%10;
         str2[2] =(char)  0x2e; //小数点
         //温度小数部分
          str2[3] = 0X30+TL_data/10;
          str2[5] = 0X27;  //"'"
          str2[6] = 0X43;  //"C"
}

 

void main (void)
{
          uchar i,n=0x40,m;
          WDTCTL = WDTPW + WDTHOLD;      
          TACTL|= TASSEL_2 + ID_3;
          init(); 
          
          while(1)
          {
                    read_TRH();
                    //写字符
                     for(i=0;i<=7;i++)
                    {
                            lcd_dis_pos(i);    //显示字符
                            write_data(dis1);
                            lcd_dis_pos(n+i);    //显示字符
                            write_data(dis2);
                    }
                   //写湿度数据
                   m=0x08;
                   for(i=0;i<=7;i++)     
                   {
                           lcd_dis_pos(m);
                           write_data(str1);
                           m++;
                  }
                  //写温度数据
                  m=0x48;
                  for(i=0;i<=7;i++)     
                  {
                           lcd_dis_pos(m);
                           write_data(str2);
                           m++;

                   }

        }     
}

kakaer

以前调DHT11是比较纠结，在操作IIC时还要保持总线状态很久时间，具体细节忘记了，下面是代码，STM32 ,MDK, 软件模拟IIC(PS:硬件IIC我弄很久都搞不定).


u16 Get_SHT11(void)
{ static u16 step=0,dey;
  static value humi_val,temp_val;
  float dew_point;
  static unsigned char error =0;
  unsigned char Hbyte,Lbyte,crc;

OsTaskStart();

           s_transstart();              //transmission start
          //send command to sensor
          error+=s_write_byte(MEASURE_TEMP);
          OsDelay(30,1);
          //for (i=0;i<65535;i++) if((READ_SDA())==0) break;//wait until sensor has finished the measurement
          if(READ_SDA()) error+=1;      // or timeout (~2 sec.) is reached
          Hbyte =s_read_byte(ACK);      //read the first byte (MSB)
          Lbyte =s_read_byte(ACK);      //read the second byte (LSB)
          crc=s_read_byte(noACK);       //read checksum
          temp_val.i=0;
          temp_val.i |= Hbyte<<8;       //read the first byte (MSB)
          temp_val.i |= Lbyte;          //read the second byte (LSB)
          temp_val.crc =crc;            //read checksum
               
          s_transstart();              //transmission start
          //send command to sensor
          error+=s_write_byte(MEASURE_HUMI);
          OsDelay(30,2);
          //for (i=0;i<65535;i++) if((READ_SDA())==0) break;//wait until sensor has finished the measurement
          if(READ_SDA()) error+=1;      // or timeout (~2 sec.) is reached
          Hbyte =s_read_byte(ACK);      //read the first byte (MSB)
          Lbyte =s_read_byte(ACK);      //read the second byte (LSB)
          crc=s_read_byte(noACK);       //read checksum
          humi_val.i=0;
          humi_val.i |= Hbyte<<8;       //read the first byte (MSB)
          humi_val.i |= Lbyte;          //read the second byte (LSB)
          humi_val.crc =crc;            //read checksum

      if(error!=0) s_connectionreset();                 //in case of an error: connection reset
      else
          {     humi_val.f=(float)humi_val.i;                   //converts integer to float
                temp_val.f=(float)temp_val.i;                   //converts integer to float
                calc_sth11(&humi_val.f,&temp_val.f);            //calculate humidity, temperature
                dew_point=calc_dewpoint(humi_val.f,temp_val.f); //calculate dew point
                printf("SHT11: temp:%5.1fC, humi:%5.1f%%, dew point:%5.1fC \r\n",temp_val.f,humi_val.f,dew_point);
      }
          error=0;
OsDelay(50,3);
OsTaskReloop();
}

//----------------------------------------------------------------
void iicDelay(u16 us)
{ u16 i;
  for(i=0;i   {
  }
}
//----------------------------------------------------------------
void s_connectionreset(void)
{ unsigned char i;

   //配置端口PB6,7为OD模式
  // GPIOB->CRL &=~(0x88000000);
  iicDelay(1);
  GPIO_SetBits(GPIOB, GPIO_Pin_7);//SDA=1;
  GPIO_ResetBits(GPIOB, GPIO_Pin_6);//SCL=0;
  iicDelay(1);
  for(i=0;i<9;i++)                  //9 SCK cycles
  { GPIO_SetBits(GPIOB, GPIO_Pin_6);//SCK=1;
    iicDelay(1);
    GPIO_ResetBits(GPIOB, GPIO_Pin_6);//SCK=0;
        iicDelay(1);
  }

   GPIO_SetBits(GPIOB, GPIO_Pin_6);//SCK=1;
   iicDelay(1);
   GPIO_ResetBits(GPIOB, GPIO_Pin_7);//SDA=0;
   iicDelay(1);
   GPIO_ResetBits(GPIOB, GPIO_Pin_6);//SCK=0;
   iicDelay(1);
   GPIO_SetBits(GPIOB, GPIO_Pin_6);//SCK=1;
   iicDelay(1);
   GPIO_SetBits(GPIOB, GPIO_Pin_7);//SDA=1;
   iicDelay(1);
  //配置端口PB6.7为复用OD模式
  //GPIOB->CRL |=0x88000000  ;
  iicDelay(1);
}
//----------------------------------------------------------------
char s_write_byte(unsigned char value)
{  unsigned char i,error=0;  

  for (i=0x80;i>0;i/=2)             //shift bit for masking
  { if (i & value) SDA_H();          //masking value with i , write to SENSI-BUS
    else SDA_L();
        iicDelay(1);                        
    SCL_H();                          //clk for SENSI-BUS
    iicDelay(1);        //pulswith approx. 5 us   
    SCL_L();
        iicDelay(1);
  }
  SDA_H();                           //release DATA-line
  iicDelay(1);
  SCL_H();                            //clk #9 for ack
  iicDelay(1);
  error=READ_SDA();                       //check ack (DATA will be pulled down by SHT11)
  SCL_L();
  iicDelay(1);        
  return error;                     //error=1 in case of no acknowledge

}

//----------------------------------------------------------------------------------
char s_read_byte(unsigned char ack)
{
  unsigned char i,val=0;
  
  SDA_H();
  iicDelay(1);                           //release DATA-line
  for (i=0x80;i>0;i/=2)             //shift bit for masking
  {
    SCL_H();                          //clk for SENSI-BUS
    iicDelay(1);
        if (READ_SDA()) val=(val | i);        //read bit  
    SCL_L();
        iicDelay(1);        
  }
  if(ack)SDA_L();else SDA_H();      //in case of "ack==1" pull down DATA-Line
  iicDelay(1);
  SCL_H();                            //clk #9 for ack
  iicDelay(1);          //pulswith approx. 5 us
  SCL_L();         
  iicDelay(1);
  SDA_H();                           //release DATA-line
  iicDelay(1);
  return val;

}
//----------------------------------------------------------------
//       _____          ________
// DATA:      |_______|
//           ___     ___
// SCK : ___|   |___|   |______
void s_transstart(void)
{  
   iicDelay(1);
   SCL_H();//SCK=1;
   iicDelay(1);
   SDA_L();//DATA=0;
   iicDelay(1);
   SCL_L();//SCK=0;
   iicDelay(1);
   SCL_H();//SCK=1;
   iicDelay(1);
   SDA_H();//DATA=1;   
   iicDelay(1);
   SCL_L();//SCK=0;
   iicDelay(1);                        
}
//----------------------------------------------------------------
// resets the sensor by a softreset
char s_softreset(void)
{ unsigned char error=0;  

  s_connectionreset();              //reset communication
  error+=s_write_byte(RESET);       //send RESET-command to sensor
  return error;                     //error=1 in case of no response form the sensor
}
//----------------------------------------------------------------
// reads the status register with checksum (8-bit)
char s_read_statusreg(unsigned char *p_value, unsigned char *p_checksum)
{  unsigned char error=0;

  s_transstart();                   //transmission start
  error=s_write_byte(STATUS_REG_R); //send command to sensor
  *p_value=s_read_byte(ACK);        //read status register (8-bit)
  *p_checksum=s_read_byte(noACK);   //read checksum (8-bit)  
  return error;                     //error=1 in case of no response form the sensor
}
//----------------------------------------------------------------
// writes the status register with checksum (8-bit)
char s_write_statusreg(unsigned char *p_value)
{  unsigned char error=0;

  s_transstart();                   //transmission start
  error+=s_write_byte(STATUS_REG_W);//send command to sensor
  error+=s_write_byte(*p_value);    //send value of status register
  return error;                     //error>=1 in case of no response form the sensor
}
//----------------------------------------------------------------
// makes a measurement (humidity/temperature) with checksum
char s_measure(u16 *p_value, unsigned char *p_checksum, unsigned char mode)
{ unsigned error=0;
  u32 i;
  unsigned char Hbyte,Lbyte,crc;

  s_transstart();                   //transmission start
  switch(mode){                     //send command to sensor
    case TEMP : error+=s_write_byte(MEASURE_TEMP); break;
    case HUMI : error+=s_write_byte(MEASURE_HUMI); break;
    default     : break;  
  }
  for (i=0;i<65535*100;i++) if((READ_SDA())==0) break;  //wait until sensor has finished the measurement
  if(READ_SDA()) error+=1;                                        // or timeout (~2 sec.) is reached
  Hbyte =s_read_byte(ACK);                 //read the first byte (MSB)
  Lbyte =s_read_byte(ACK);              //read the second byte (LSB)
  crc=s_read_byte(noACK);       //read checksum
  
  *p_value=0;
  *p_value |= Hbyte<<8;                 //read the first byte (MSB)
  *p_value |= Lbyte;              //read the second byte (LSB)
  *p_checksum =crc;       //read checksum
  return error;
}

//----------------------------------------------------------------
// calculates temperature and humidity [%RH]
// input :  humi [Ticks] (12 bit)
//          temp [Ticks] (14 bit)
// output:  humi [%RH]
//          temp  
void calc_sth11(float *p_humidity ,float *p_temperature)
{ const float C1=-4.0;              // for 12 Bit
  const float C2=+0.0405;           // for 12 Bit
  const float C3=-0.0000028;        // for 12 Bit
  const float T1=+0.01;             // for 14 Bit @ 5V
  const float T2=+0.00008;           // for 14 Bit @ 5V
  float rh=*p_humidity;             // rh:      Humidity [Ticks] 12 Bit
  float t=*p_temperature;           // t:       Temperature [Ticks] 14 Bit
  float rh_lin;                     // rh_lin:  Humidity linear
  float rh_true;                    // rh_true: Temperature compensated humidity
  float t_C;                        // t_C   :  Temperature
  t_C=t*0.01 - 40;                  //calc. temperature from ticks to
  rh_lin=C3*rh*rh + C2*rh + C1;     //calc. humidity from ticks to [%RH]
  rh_true=(t_C-25)*(T1+T2*rh)+rh_lin;   //calc. temperature compensated humidity [%RH]
  if(rh_true>100)rh_true=100;       //cut if the value is outside of
  if(rh_true<0.1)rh_true=0.1;       //the physical possible range
  *p_temperature=t_C;               //return temperature
  *p_humidity=rh_true;              //return humidity[%RH]
}
//----------------------------------------------------------------
// 计算露点
// input:   humidity [%RH], temperature
// output:  dew point
float calc_dewpoint(float h,float t)
{ float logEx,dew_point;
  logEx=0.66077+7.5*t/(237.3+t)+(log10(h)-2);
  dew_point = (logEx - 0.66077)*237.3/(0.66077+7.5-logEx);
  return dew_point;
}

兜揣阳光

高手。。。能不能看一下我的程序有什么问题呢？调试了三天了，还是没有结果，挺郁闷的。。。

眼大5子

以前我也玩过，我用的是SHT10的，自己焊的，我好像有在DATA引脚加了个上拉电阻，你看看会不会是数据线太长了，没有加上拉电阻。

兜揣阳光

我也加了5K的上拉电阻，但不知道为什么还是木有结果。你能不能看一下我的程序有问题没。。。

yyh9037

兜揣阳光 发表于 2012-4-5 14:24
我也加了5K的上拉电阻，但不知道为什么还是木有结果。你能不能看一下我的程序有问题没。。。

您好，您的DHT11出来没？我最近也在调，但是感觉DHT11老是没响应，