/home/daqweb/fgddaq/c8051/Protocols/SHT7x_protocol.h File Reference

Defines
#define	SHT7x_DELAY   5
#define	SHT7x_SHORT_DELAY   0.3
#define	ACK   0
#define	NACK   1
#define	ERROR   0
#define	DONE   1
Functions
void	SHT7x_Init (int humsen)
void	SHT7x_ClockOnce (int humsen)
void	SHT7x_ConnectionReset (int humsen)
void	SHT7x_TransStart (int humsen)
unsigned char	SHT7x_FCS_Step (unsigned int msg, unsigned char fcs) reentrant
unsigned char	SHT7x_WriteByte (unsigned char dataToSend, int humsen)
unsigned char	SHT7x_ReadByte (unsigned char read_flag, int humsen)
void	SHT7x_ClockOnce2 (int humsen)
Variables
sbit	SHT7x_DATA1 = SHT_DATA1
sbit	SHT7x_SCK1 = SHT_SCK1

---

Define Documentation

#define ACK   0

#define DONE   1

#define ERROR   0

#define NACK   1

#define SHT7x_DELAY   5

#define SHT7x_SHORT_DELAY   0.3

---

Function Documentation

void SHT7x_ClockOnce

(

int

humsen

)

                                {
  if(humsen==1)
  {
    SHT7x_SCK1 = 0;
    delay_us(SHT7x_DELAY);
    SHT7x_SCK1 = 1;
    delay_us(SHT7x_DELAY);
    SHT7x_SCK1 = 0;
  }
#ifdef MORETHANONEHUM
  else if(humsen==2)
  {
    SHT7x_SCK2 = 0;
    delay_us(SHT7x_DELAY);
    SHT7x_SCK2 = 1;
    delay_us(SHT7x_DELAY);
    SHT7x_SCK2 = 0;
  }
#endif
}

void SHT7x_ClockOnce2

(

int

humsen

)

void SHT7x_ConnectionReset

(

int

humsen

)

                                      {
  unsigned char i;
  if(humsen==1)
  {
    //Initial state
    SHT7x_DATA1=1; 
    SHT7x_SCK1=0; 
  }
#ifdef MORETHANONEHUM
  else if(humsen==2)
  {
    SHT7x_DATA2=1;
    SHT7x_SCK2=0;
  }
#endif
  for(i=0;i<9;i++) {           //9 SCK cycles
      SHT7x_ClockOnce(humsen);
    }
//  SHT7x_TransStart(humsen);    //transmission start
}        

unsigned char SHT7x_FCS_Step	(	unsigned int	msg,
		unsigned char	fcs
	)

                                                                            {
   return SHT7x_FCS_data[(msg ^ fcs)];
}

void SHT7x_Init

(

int

humsen

)

                           {
  
  SHT7x_ConnectionReset(humsen);
}

unsigned char SHT7x_ReadByte	(	unsigned char	read_flag,
		int	humsen
	)

                                                                 {

  signed char i;
  unsigned char dataReceived=0, din=0;
  if(humsen==1)
  {
    SHT7x_DATA1 = 1; //release SHT7x_DATA line
    //NW Read when the clock line is high 
    for (i = 7; i >= 0; i--) { 
      din = SHT7x_DATA1;
      SHT7x_ClockOnce(humsen);
      dataReceived |= (din << i);  
    }

    SHT7x_DATA1 = read_flag;    //Sending ACK/NACK. In case of ACK pull the SHT7x_DATA line low
    SHT7x_ClockOnce(humsen);    //The 9th clock cycle
    SHT7x_DATA1 = 1;            //Release the SHT7x_DATA line


  }
#ifdef MORETHANONEHUM
  else if(humsen==2)
  {
    SHT7x_DATA2=1; //release SHT7x_DATA line
    //NW Read when the clock line is high 
    for (i = 7; i >= 0; i--) { 
      din = SHT7x_DATA2;
      SHT7x_ClockOnce(humsen);
      dataReceived |= (din << i);  
    }

    SHT7x_DATA2 = read_flag;    //Sending ACK/NACK. In case of ACK pull the SHT7x_DATA line low
    SHT7x_ClockOnce(humsen);    //The 9th clock cycle
    SHT7x_DATA2 = 1;            //Release the SHT7x_DATA line
  }
#endif
  return dataReceived;
}

void SHT7x_TransStart

(

int

humsen

)

                                 {
  if(humsen==1) {
    //Initial state
    SHT7x_DATA1=1; 
    delay_us(SHT7x_DELAY);
    SHT7x_SCK1=1;
    delay_us(SHT7x_DELAY);
    SHT7x_DATA1=0;
    delay_us(SHT7x_DELAY);
    SHT7x_SCK1=0;
    delay_us(SHT7x_DELAY);    //low pulse, but in the sample code, it used 3 _nop_();
    SHT7x_SCK1=1;
    delay_us(SHT7x_DELAY);
    SHT7x_DATA1=1;
    delay_us(SHT7x_DELAY);
    SHT7x_SCK1=0;
  }
#ifdef MORETHANONEHUM
  else if(humsen==2) {
    //Initial state
    SHT7x_DATA2=1; 
    delay_us(SHT7x_DELAY);
    SHT7x_SCK2=1;
    delay_us(SHT7x_DELAY);
    SHT7x_DATA2=0;
    delay_us(SHT7x_DELAY);
    SHT7x_SCK2=0;
    delay_us(SHT7x_DELAY);    //low pulse, but in the sample code, it used 3 _nop_();
    SHT7x_SCK2=1;
    delay_us(SHT7x_DELAY);
    SHT7x_DATA2=1;
    delay_us(SHT7x_DELAY);
    SHT7x_SCK2=0;
  }
#endif
}

unsigned char SHT7x_WriteByte	(	unsigned char	dataToSend,
		int	humsen
	)

                                                                   {

  signed char xdata i;
  unsigned char xdata status;
  if(humsen == 1) {  
      for(i = 7; i >= 0; i--) {
        SHT7x_DATA1 = (dataToSend >> i) & 0x01;
      SHT7x_ClockOnce(humsen);  
    }

    SHT7x_DATA1 = 1;          //Release SHT7x_DATA line
    delay_us(10);
    SHT7x_ClockOnce(humsen);  // ACK reception of the CMD
    SHT7x_DATA1 = 1;          //Release SHT7x_DATA line

  }
#ifdef MORETHANONEHUM
  else if(humsen==2)
  {
      for(i = 7; i >= 0; i--) {
        SHT7x_DATA2 = (dataToSend >> i) & 0x01;
      SHT7x_ClockOnce(humsen);  
    }

    SHT7x_DATA2 = 1;          //Release SHT7x_DATA line
    delay_us(10);
    SHT7x_ClockOnce(humsen);  // ACK reception of the CMD
    SHT7x_DATA2 = 1;          //Release SHT7x_DATA line


  }  
#endif
  if (status == NACK)         //1 in case of No acknowledge
     return ERROR;             
  return DONE;
}

---

Variable Documentation

sbit SHT7x_DATA1 = SHT_DATA1

sbit SHT7x_SCK1 = SHT_SCK1

---