Sensirion SHT11 with a PIC16F628-20

[yohanfx]

I want to program SHT11, with language PBP or Pbasic
want to know the temperature and humidity with SHT11.
please help me ....

[Charles Linquis]

I have successfully used the code below with an 18F2321.
It should work the same with a 16F part.

I found it somewhere here on the forum, and it works great.

'------------------ Read SHT71 Temperature / Humidity Sensor -------------------
        
ReadSHT71:
    SHTCommand = ReadTemp
    gosub Initialize
    GOSUB TransmissionStart
    GOSUB IssueCMD
    gosub ConvertToCelsius
    
    
    SHTCommand = ReadHumidity
    gosub Initialize
    GOSUB TransmissionStart
    GOSUB IssueCmd
    gosub ConvertToRH

    TEMPC = (TempC/100) - 2 
    TempC.7 = SignC      
    RHTempComp = RHTempComp/100
    RETURN
   
    

'--------------------- Calculate Relative Humidity -----------------------------

ConvertToRH:
' 12 Bit    RHLinear = -4 + 0.0405 * DataOutput -0.0000028 * DataOutput^2
    w = 405 * RawData
    w = div32 100
    x = RawData * RawData
    x = div32 1000
    x = x * 28
    x = div32 100
    RHLinear = w - x - 400

'---------- Calculate Relative Humidity with Temperature Compensation ----------

    w = (8 * RawData + 1000) / 10
      IF SignC = 0 THEN      ' "+"  
        if tempC > 2500 then
            x = (tempC - 2500) * w
            x = div32 100
            RHTempComp = RHLinear + x / 100
            else
            x = (2500 - tempc) * w
            x = div32 100
            RHTempComp = RHLinear - x / 100
        endif
        else
        x = (2500 + tempC) * w
        x = div32 10000
        RHTempComp = RHLinear - x
    endif
    return

'---------------------------- Initialize the Sensor ----------------------------

Initialize:
    high DataPin                   ; Start condition
    low clk
    for i = 1 to 10
        high clk
        pause 1
        low clk
        pause 1
    next i                          ; Leaves clock low

    return

'---------------------------- Get Data from Sensor -----------------------------

IssueCmd:
    Pause 2
    low Clk
    shiftout DataPin,clk,1,[SHTCommand\8]       ' Send command byte
    input DataPin                                                            

WaitForAck:
     x = 0
WaitForAck2:
    IF DataPin = 1 THEN
      x = x + 1
      if x = 0 then goto NoAck
      Pauseus 2
      GotoWaitForAck2
    ENDIF  
      
    High Clk
    pause 10                                    ' Issue ACK from PIC
    low clk
    
    pause 10                                    ' Make certain we don't move forward on a glitch

    WHILE DataPin:WEND
                                     
   
    shiftin DataPin,clk,0,[RawData.byte1\8]     ' Get the first byte, 8 bits
    low DataPin
    
    HIGH Clk
    PAUSE 10
    LOW Clk
    pulsout clk,10                              ' Send NACK
    shiftin DataPin,clk,0,[RawData.byte0\8]     ' Get the second byte, 8 bits


    low DataPin
    pulsout clk,10                              ' Send acknowledge
    shiftin DataPin,clk,0,[crc\8]               ' Get third byte, 8 bits, CRC
    high DataPin
    pulsout clk,10                              ' Send acknowledge
    input DataPin                               ' End of Transmission
    input clk

    ERR = 0
    return

NoAck:
    ERR = 1
    RETURN

'---------------------------- Start Transfer -----------------------------------

TransmissionStart:
    HIGH DataPin      ; Make sure it is high
    Pause 1
    high clk
    pause 1
    low DataPin
    pause 1
    low clk
    pause 1
    high clk
    pause 1
    high DataPin
    pause 1
    low clk
    return

'----------------------------- Raw Data to Degrees C ---------------------------


ConvertToCelsius:
' 14 Bit    Temperature = -40.00 + 0.01 * DataOutout
    if RawData => 4000 then
        tempC = RawData - 4000
        SignC = 0
               
        else
        tempC = 4000 - RawData         ; Negative Temps
        SignC = 1

    endif
    return

[yohanfx]

what software you use as a compiler?
pardon my beginner programing and
program how to display the sensor readings of temperature and humidity SHT11 to 16bit and two-line LCD ....
thanks very much