Code for SHT21

[Mike2545]

mpgmike, I got the sensor to respond to my finger temp difference. Here is the code so far:

Yes, yes, I am prototyping on a Stamp :/

' {$STAMP BS2p}
' {$PBASIC 2.0}

  tf    VAR Byte
  tc    VAR Byte
  rawT  VAR Word
  rawRH VAR Byte

  PAUSE 250                                     ' let DEBUG window open
  DEBUG CLS
  DEBUG "SHT21 Demo", CR
  DEBUG "----------", CR

Main:

I2COUT 0 ,%10000000, [%11100011]
  PAUSE 50
I2CIN  1 , %10000001, [rawT]
  DEBUG 2, 0, 3
  DEBUG "rawT...... "
  DEBUG  DEC rawT, 11, CR
  rawT= rawT <<2
  tC = (rawT & $fffc) ** 17572 - 4685
  DEBUG "Deg C......", DEC tC
  PAUSE 500


  GOTO main

Getting elevated readings on the SHT21
The SHT21 temp says my room is 42°C (107.6°F) Actual temperature is ~ 23.8°C (75°F)
rawT @ 42°C = 111

[richard]

don't know much about stamp code but here goes

from the sensiron web example

//================================================== ============================
float SHT2x_CalcTemperatureC(u16t u16sT)
//================================================== ============================
{
ft temperatureC; // variable for result
u16sT &= ~0x0003; // clear bits [1..0] (status bits)
//-- calculate temperature [°C] --
temperatureC= -46.85 + 175.72/65536 *(ft)u16sT; //T= -46.85 + 175.72 * ST/2^16
return temperatureC;
}

the reading is not shifted <<2 places the two lsb are just masked off

so
rawT= rawT <<2
becomes
rawT= rawT & ~3 ;ie %1111111111111100

I2COUT 0 ,%10000000, [%11100011]

is hold master mode is that what you need ?

try
I2COUT 0 ,%10000000, [%11110011]

might be better

I2COUT 0 ,%10000000, [%11100011]
PAUSE 50 is this long enough at max resoloution ?
I2CIN 1 , %10000001, [rawT]

rawT @ 42°C = 111

by my calcs rawT should be 33132 @ 42°C

what rawT do you actually get ?