LPC55S69 Inconsistent ADC Temperature Coefficients between SDK2.8.2 and UM11126

[gertvb]

Hallo Everyone!

Just an observation on inconsistent ADC Temperature coefficient values between UM11126 vs values used by Configtool/SDK 2.8.2

If I create a New C/C++ project from scratch in MCUXpresso using SDK2.8.2 for the LPC55s69 and add the lpadc driver, it adds the files fsl_lpadc.c and .h to the project, which also includes the the function:

float LPADC_MeasureTemperature(ADC_Type *base, uint32_t commandId, uint32_t index)

In the MeasureTemperature function it uses FSL_FEATURE_LPADC_TEMP_PARAMETER_A, FSL_FEATURE_LPADC_TEMP_PARAMETER_B &  FSL_FEATURE_LPADC_TEMP_PARAMETER_ALPHA, values defined in LPC55S69_cm33_core0_FEATURES.h

The values defined in UM11126 (39.7.6 p769) differs from the values used in LPC55S69_cm33_core0_FEATURES.h

Which ones are correct for HW rev 1B?

Alpha : 8.5 vs 11.5

A : 804 vs 744.6

B : 280 vs 313.7

Regards

Gert

[Omar_Anguiano · Accepted solution]

Hello gertvb

I suggest you use the values from the SDK.

A = 744.6

B = 313.7

Alpha = 11.5

Thank you for letting us know about the difference between the parameters.

If you have more questions do not hesitate to ask me.

Best regards,

Omar