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LP-MSPM0G3507: Internal Temperature issue

Maxwell Lin
Prodigy 15 points
Part Number: LP-MSPM0G3507
Other Parts Discussed in Thread: UNIFLASH, MSPM0G3507

Tool/software:

Greetings.

While using LP-MSPM0G3507, I am facing a problem about using internal temperature sensor.

1. First of all, below picture shows the TEMP_SENSE0.DATA  which read from uniflash.

The trimed value at 0x41C4003C = 0x2EEh = 750d.

USERID and DEVICEID also displayed in it.

2. The example project from mspm0_sdk_2.1.0.03, "adc12_internal_temp_sensor_mathacl_LP_MSPM0G3507_nortos_ticlang"

The calculated value is 5 degree celsius, it is incorrect with my environment.

3.  There is an external thermistor on LP-MSPM0G3507 board which I can able to read from ADC and verified it with accurate value at 25 degree celsius.

The internal temperatue measured by ADC12 is approimate 0x323h/ 803d

Applying the formula described in TRM, the result is as same as the example does.

Vtrim = (3.3/4096)*(750-0.5) = 0.603845215

Vsample = (3.3/4096)*(803-0.5) = 0.648156738

Slope = -1.8mV/degree celsius.(provided by datasheet)

[ ( Vsample - Vtrim )/slope] + 30 = -24.6175 + 30 = 5.3824 

By Hand calculating, I got exaclty the same value with sdk example.

Bottom line: Is there anything wrong in my description above? 

If yes, please help me correct it. 

If not, what or how can I do to fix internal temperature sensor issue? 

Example code is alos attached.  Thank you.

adc12_internal_temp_sensor_mathacl_LP_MSPM0G3507_nortos_ticlang.zip

  • 0
    TI__Mastermind 28075 points

    Hi Maxwell,

    I don't see anything wrong with your math. Testing the latest SDK code on my end the temperature sensor values look correct.

    Can you let me know what the part marking on your device is? If you can share a picture that would be great. There were some early samples that had bad temperature sensor trim values and that could be what you are seeing here. 

    Best Regards,
    Brandon

  • 0 in reply to Brandon Fisher94
    Prodigy 15 points

    Hi Brandon.

    Thanks for your reply.

    Here's the picture of LP-MSPM0G3507:

    The marking on MSPM0G3507 :

    First Line      : X37AE14W G4

    Second Line:  M0G3507S 

    Thanks again for your help! Much appreciate.

  • +1 in reply to Maxwell Lin
    TI__Mastermind 28075 points

    Hi Maxwell,

    Do you have another launchpad you can try? This launchpad has a preproduction device (Indicated by the "X" included in the device marking).

    There were many of these x marked devices that had improper trim of the temperature sensor, your device appears to have that bad trim value as well. 

    On a production device, your method and the example will work as expected.

    Any new launchpad shipped from us should have a non-x marked/preproduction device. 

    Best Regards,
    Brandon Fisher

  • 0 in reply to Brandon Fisher94
    Prodigy 15 points

    Hi Brandon

    Thanks for your answer, I will order another launch pad or just test on our board.

    Let's close this issue.

    Thanks again for your great help!