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Original question:

MSPM0L1306: MSPM0L1306 : ADC channel Configuration

MSPM0L1306: Root cause pls for ADC Channal 2 Pin (PA25) failure - Not even worked as GPIO - in LP-MSPM0L1306 board

Selvam Krishnan
Prodigy 140 points
Part Number: MSPM0L1306

Tool/software:

Good day all,

Summary:

Shall we get root cause behind "ADC Channal 2 Pin (PA25) failure - not even worked as normal GPIO - in MSPM0L1306?

Details:

We were tried to analyze the ADC via Chanel 2 by monitoring the DC voltage from 1 to 3V with the help of one LP-MSPM0L1306 board.

After one day, we faced the wrong high value while reading DC voltage value. It is working with another one new LP-MSPM0L1306 board

We tried to analyze the root cause,

it looks we are getting around 1.6-2.0 V at ADC input pin PA25 without connecting any input into this pin.

Also, it looks normal toggling also not happening with this pin. Toggling happening with another GPIO pin like PA0

So that we conclude that PA25 - ADC Channel 2 pin gone. 

We would like to know that what might be the cause of this failure of ADC channel 2 pin in LP-MSPM0L1306.

Please help us to find the root cause behind this failure of ADC channel 2 pin in LP-MSPM0L1306.

Thanks

Selvam

  • 0
    TI__Expert 3450 points

    Hi Selvam,

    I have done the experiments on ADC Channel2 (PA15) with LP-MSPM0L1306, and everything works fine here so far. So I need to confirm a few questions.

    Selvam Krishnan said:
    it looks we are getting around 1.6-2.0 V at ADC input pin PA25 without connecting any input into this pin.

    You have mentioned that you just connect PA25 to the outside voltage without any other input, did you notice that on the schematic PA25 is related to Photodiode Circuit and Thermistor Circuit, as shown in the below, have you removed these related jumpers on the board to disable these functions?

    Best Regards,

    Peter

  • 0 in reply to Peter Jiang
    Prodigy 140 points

    Hi Peter,

    Thanks for response and experiments.

    Yes, we removed the Jumper J4 as well as J1, still we are getting this voltage, sometime around 3V is coming, even after configuring to normal GPIO output.

    It looks this pin PA25 is gone, so that as of now we are using PA27. 

    We surprised how that pin alone got failed.? and what will be root cause to correct in future. 

    Thanks

    Selvam