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MSPM0G3507: The Vref of internal temperature sensor.

Luke Chen
Expert 5090 points
Part Number: MSPM0G3507

Hi champs,

In TRM we say TEMP_SENSE0.DATA is the ADC result code based on 12-bit mode and a 1.4-V reference.

My question is when we use internal temperature sensor, should we configure Vref to internal 1.4V reference for accuracy? Or we can configure Vref to other reference source, VDDA for example?

Regards,

Luke

  • 0
    TI__Mastermind 45485 points

    Hi Luke,

    The TRM is wrong about the TEMP_SENSE0.DATA is the ADC result code based on 12-bit mode and a 1.4-V reference. It is actually using 3.3V VDDA as reference. 

    In the latest SDK, they all use 3.3V for calculation.

    Best regards,

    Cash Hao

  • 0 in reply to Cash Hao11
    TI__Expert 5090 points

    Hi Cash,

    Another question is in the temperature sensor example project, we use _IQ15(3.45) to calculate Vtrim value, not use _IQ15(3.30), why?

    /*
    * Convert TEMP_SENSE0 result to equivalent voltage:
    * Vtrim = (3.3*(TEMP_SENSE0 -0.5))/(2^12)
    */

    qVTrim = _IQ15div(_IQ15mpy((_IQ15(DL_SYSCTL_getTempCalibrationConstant()) -
                      _IQ15(0.5)), _IQ15(3.45)), ((uint32_t)(1) << 27));

    Regards,

    Luke

  • +1 in reply to Luke Chen
    TI__Mastermind 45485 points

    Hi Luke,

    It should use the _IQ15(3.30) for Vtrim calculation. This will be fixed in further SDK.

    Best regards,

    Cash Hao