Hello,
in our application we employ the internal temperature sensor internally connected to the 10-Bit ADC (ADC10). For the calibration of the temperature sensor we use parameters ADC25T30 and ADC25T85 from the TLV table. However, we ask ourselves, if we also need to calibrate the ADC10 itself, according to the 1.13.5.2 of the document SLAU208O. Finally, the ADC10 takes part in the readout of the internal temperature signal.
Now, trying to perform the calibration of ADC10 according to the TLV table we have another question. The SLAU208O describes two calibrations:
1.Calibration of offset and gain of ADC10 in chapter 1.13.5.2
2.Calibration of REF in chapter 1.31.5.1.
What is the correct sequence for the calibration of the temperature? We wonder, which way is correct:
Option 1: Insert raw ADC in equation (3) – one will obtain ADC(corrected) [I am referring to the original names found in SLAU208O, page 81]. However we can’t find the CAL_ADC25VREF_FACTOR in TLV, which is needed for eq. (3). Does the REF calibration according to 1.13.5.1 not refer to our MSP430F67471?
Option 2: Insert raw ADC in equation (6) – one obtains ADC(gain_corrected). In the next step, calculate ADC(final) according to the eq. (7). Finally, insert ADC(final) into the eq. (30) to get a compensated temperature value.
Option 3: For the temperature measurement, do not use the ADC offset and gain compensation from 1.13.5.2, since both TLV parameters ADC25T30 and ADC25T85 already include the compensation of the ADC’s gain and offset.
Please advise.
