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TMS320F28375S: Internal Temperature Sensor Equation

Todd Anderson78572
Guru 14640 points
Part Number: TMS320F28375S

All:

"To convert the temperature sensor reading into a temperature, pass the temperature sensor reading to the

GetTemperatureC() function in F2837xS_TempSensorConv.c"   from TRM (spruhx5f)

Is there an equation that represents what goes on in the GetTemperatureC( )?

If I pass a value of 1668, I get 29C, but how is that determined?

  • 0
    TI__Guru 60865 points
    Hi Todd,

    TI calculates a slope (deg. C / mV sensor change) + offset (reading at 0 C) for each device during production test and stores them into OTP memory.

    The function uses the above values to translate the sensor reading to a corresponding temperature.
  • 0 in reply to Devin Cottier
    Guru 14640 points
    Is there a default slope based on number of counts?
    Assume 0 offset (default).

    So, in order to get an accurate reading, you MUST call the GetTemperatureC() which then uses the gain (slope) and offset to determine degrees C.

    What if the customer does not want to include the GetTemperatureC() in his program, but he still wants to monitor the counts received in the ADC result register. I know it would not be exact, but could it give him a "ballpark" figure?

    How much variation is there from part to part, enough that GetTemperatureC() must be called?
  • 0 in reply to Todd Anderson78572
    Guru 14640 points
    Found the answer in the code:

    //
    //for pre-production devices, use these static values for slope
    //and offset
    //
    tempSensor_tempSlope = 5196;
    tempSensor_tempOffset = 1788;