c - 如何获取DSTH01 I2C通信的设备ID？

Question

我正在尝试使用 DSTH01 获取湿度和温度。但我无法获得正确的值。我得到的湿度为 -24，温度为 -50。我不知道我在哪里失踪。请指导我解决我的问题。最初，如果我获得有助于解决我的问题的设备 ID。我正在使用带有 10 MHz 晶振的 PIC18f2520。

我做了以下连接:

 PIN1-GND
 PIN2-Pull Up to 3.3 V with 10k- Microcontroller  PIN_C3
 PIN3 - Pull Up to 3.3 V with 10k-Microcontroller  PIN_C4
 PIN4 - Microcontroller  PIN_A2
 PIN5 - 3.3 V 

这是我的源代码:

 #define DSTH01_SCK  PIN_C3
 #define DSTH01_SDA  PIN_C4
 #define DSTH01_CSB  PIN_A2

 #define SDA_H output_high(DSTH01_SDA)
 #define SDA_L output_low(DSTH01_SDA)
 #define SCK_H output_high(DSTH01_SCK)
 #define SCK_L output_low(DSTH01_SCK)
 #define CS_H  output_high(DSTH01_CSB)
 #define CS_L  output_low(DSTH01_CSB)

 #define SlaveAddress      0x40
 #define RegisterAddress0  0x00
 #define RegisterAddress1  0x01
 #define RegisterAddress2  0x02
 #define RegisterAddress3  0x03
 #define RegisterAddress11 0x11

 void small_delay(void);
 void I2C_START(void);
 void I2C_STOP(void);
 void I2C_WRITE(unsigned int8 Data);
 int8 I2C_READ(void);
 void I2C_ACK(unsigned int8 a);
 int8 I2C_SEND(unsigned int8 SlaveAdd,unsigned int8 RegisterAdd,unsigned  int8 *s);
 int8 I2C_RECEIVE(unsigned int8 SlaveAdd,unsigned int8 RegisterAdd,unsigned int8 *s);
 void Temperature_READ(unsigned int8 *s);
 void RelativeHumidity_READ(unsigned int8 *s);
 int1 Check_SDA(void);

 unsigned int8 Ack;
 unsigned int8 id;
 unsigned int8 RelativeHumidity =0;
 unsigned int8 Temperature =0;
 unsigned int8 Start1=0x01;
 unsigned int8 Start2=0x11;

 void main(void)
 {    
     set_tris_c(0x80);
     delay_ms(100);delay_ms(100);  
     output_low(PIN_C3);
     output_high(PIN_C4);
     output_low(PIN_A2);
     enable_interrupts(int_rda);
     enable_interrupts(global);   
     delay_ms(100);delay_ms(100);
     delay_ms(100);delay_ms(100);
     delay_ms(100);delay_ms(100);  

     CS_L;
     I2C_RECEIVE(SlaveAddress,RegisterAddress11,&id);
     while (1)
     {
            RelativeHumidity_READ(&RelativeHumidity);
            Temperature_READ(&Temperature);
            delay_ms(100);delay_ms(100);
            delay_ms(100);delay_ms(100);
            delay_ms(100);delay_ms(100);
            printf("\r\nRelativeHumidity:%d",RelativeHumidity);
            printf("\tTemperature:%d",Temperature);
      }  
  }

void I2C_START()
{
   SDA_H;small_delay();
   SCK_H;small_delay();
   SDA_L;small_delay();
   SCK_L;small_delay();
 }
void I2C_STOP()
{
   SDA_L;small_delay();
   SCK_H;small_delay();
   SDA_H;small_delay();
}  
 void I2C_WRITE(unsigned  int8 Data)
{
   unsigned  int8 i;
   for(i=0;i<8;i++)
   {
      if(Data&0x80)
         {SDA_H;small_delay();}
      else
         SDA_L;small_delay();
         SCK_H;small_delay();
         SCK_L;small_delay();
         Data<<=1;
   }
   SDA_H;small_delay();
   SCK_H;small_delay();
   //if(SDA==1)
   if(Check_SDA()==1)
      Ack=0;
   else
      Ack=1;
      SCK_L;small_delay();
}  
unsigned  int8 I2C_READ()
{
   unsigned  int8 Data=0;
   unsigned  int8 i;
   SDA_H;
   for(i=0;i<8;i++)
   {
      SCK_L;small_delay();
      SCK_H;small_delay();
      Data<<=1;
      //if(SDA==1)
     if(Check_SDA()==1)
      Data=Data+1; 
   }
   SCK_L;small_delay();
   return Data;
}
void I2C_ACK(unsigned  int8 a)
{
   if(a==0)
      {SDA_L;small_delay();}
   else
      SDA_H;small_delay();
      SCK_H;small_delay();
   SCK_L;small_delay();
}
unsigned int8 I2C_SEND(unsigned  int8 SlaveAdd,unsigned  int8 RegisterAdd,unsigned  int8 *s)
{
   SlaveAdd=SlaveAdd<<1;
   I2C_START();
   I2C_WRITE(SlaveAdd);
   if(Ack==0)
      return 0;
   I2C_WRITE(RegisterAdd);
      if(Ack==0)
         return 0;
      I2C_WRITE(*s);
         if(Ack==0)
         return 0;
         I2C_STOP();
   return 1;
}
unsigned  int8 I2C_RECEIVE(unsigned  int8 SlaveAdd,unsigned  int8 RegisterAdd,unsigned  int8 *s)
{
   SlaveAdd = SlaveAdd<<1;
   I2C_START();
   I2C_WRITE(SlaveAdd);
   if(Ack==0)
   return 0;
   I2C_WRITE(RegisterAdd);
   if(Ack==0)
   return 0;
   I2C_START();

   I2C_WRITE(SlaveAdd+1);
   if(Ack==0)
      return 0;
      *s=I2C_READ();
      I2C_ACK(1);
      I2C_STOP();
   return 1;
}
void RelativeHumidity_READ(unsigned  int8 *s)
{
   unsigned  int8 Status=1;
   unsigned  int8 RelativeHumidityH;
   unsigned  int8 RelativeHumidityL;
   unsigned  int16 RelHum;
   I2C_SEND(SlaveAddress,RegisterAddress3,&Start1);
   while(Status==1)
   {
      I2C_RECEIVE(SlaveAddress,RegisterAddress0,&Status);
   }
   I2C_RECEIVE(SlaveAddress,RegisterAddress1,&RelativeHumidityH);
   I2C_RECEIVE(SlaveAddress,RegisterAddress2,&RelativeHumidityL);
   RelHum=RelativeHumidityH;
   RelHum=RelHum<<8;
   RelHum+=RelativeHumidityL;
   RelHum=RelHum>>4;
   *s=RelHum/16-24;
}
void Temperature_READ(unsigned  int8 *s)
{
   unsigned  int8 Status=1;
   unsigned  int8 TemperatureH;
   unsigned  int8 TemperatureL;
   unsigned  int16 Temp;
   I2C_SEND(SlaveAddress,RegisterAddress3,&Start2);
   while(Status==1)
   {
      I2C_RECEIVE(SlaveAddress,RegisterAddress0,&Status);
   }
   I2C_RECEIVE(SlaveAddress,RegisterAddress1,&TemperatureH);
   I2C_RECEIVE(SlaveAddress,RegisterAddress2,&TemperatureL);
   Temp=TemperatureH;
   Temp<<=8;
   Temp+=TemperatureL;
   Temp>>=2;
   *s=Temp/32-50;
}
int1 Check_SDA(void)
{
   int1 a;
   set_tris_c(0x90);//10010000,RX,0,0,SDA,0,0,0,0
   small_delay();
   if(input(DSTH01_SDA)){a =1; }
   else{a = 0;}
   set_tris_c(0x80);//10000000
   small_delay();
   return a;
}
void small_delay(void)
{
   char a;
   for(a = 0;a < 10;a++);
}

Answer 1

更新 我之前删除了这个答案，因为我认为它是错误 和无用，但也许这里毕竟有 OP 的东西。 ..

如何从 unsigned 变量中获取负值？

查看 DSTH01 data sheet , % 相对湿度由 (RH/16)-24 计算，这表明您的代码有不必要的行

RelHum=RelHum>>4;               // remove this line
*s=RelHum/16-24;

接下来，数据表说温度是由 (TEMP/32)-50 计算的，这表明您的代码还有另一行不必要的行

Temp>>=2;                       // remove this line
*s=Temp/32-50;

假设您已正确读取 I2C 数据。

数据表在表 6 中显示湿度为 11 位的错误。它在表 8 中也有一个错误，它没有显示温度，而是重复了与湿度相同的表，表 6。

我认为你正在做额外的除法，因为数据表说结果分别是 12 位和 14 位，但推断是数据是左对齐的，这就是除法(实际上是移位)的原因需要 - 但只有一次!我建议您按照数据表中的说明进行转换:使用 DATAh 和 DATAl，这些在右侧用零填充。所以代码可能会更好

RelHum = (RelHum >> 4) - 24;    // div 16
*s = (unsigned int8)RelHum;     // now cast to 8-bit

和

Temp = (Temp >> 5) - 50;        // div 32
*s = (unsigned int8)Temp;       // now cast to 8-bit