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MSP430FR2433: Minimizing P1.1 current @ V=1.65V

Hideaki Nambu
Mastermind 9165 points

Part Number: MSP430FR2433
Other Parts Discussed in Thread: MSP-EXP430FR2433

Hello,
Please open the attached PNG file.
The file shows a P1.1 input I-V plot.
Could you please advise how to minimize the P1.1 current @ V=1.65V ?


p.s.
My customer uses the pin as ADC input. Therefore SYSCFG.ADCPCTL1 = 1.

** [edit] My test result below is not correct. I forgot to remove J11 on the MSP-EXP430FR2433. After the J11 is removed, the current increase was not found.

CCS740 project:

/cfs-file/__key/communityserver-discussions-components-files/166/msp430fr243x_5F00_LPM3_5F00_01_5F00_edit180405_5F00_1_5F00_e2e-ccs740.zip

  • 0
    TI__Expert 7555 points
    Hi Hideaki,

    The code example that you link to doesn't have any ADC setup; it initializes the IO's to output low. In your case, are you using this example and also setting SYSCFG.ADCPCTL1 = 1? What is the MCU supply voltage during this test, and what hardware is being used (target socket board, LaunchPad, your own hardware, ect.).

    Regards,
    Walter
  • 0 in reply to Walter Schnoor
    Mastermind 9165 points

    Walter,
    Thank you for your response.

    ###
    >>>
    are you using this example and also setting SYSCFG.ADCPCTL1 = 1?
    <<<

    Yes.
    In [mspp430fr243x_LPM3_01.c], Ln86, I added my code:
    #if 1 // n
    SYSCFG2 = 0x0002;
    #endif


    ###
    >>>
    What is the MCU supply voltage during this test
    <<<

    It should be 3.3V.


    ###
    >>>
    , and what hardware is being used
    <<<

    MSP-EXP430FR2433.


    I'm sorry, my explanation was not sufficient.

    And let me add:

    - I think my choice of the sample code is good. My customer application spends most of the lifetime in LPM3. P1.1 voltage is converted, thank you for your pointing about it, but we focus on the LPM3. We would like to minimize the P1.1 current when ADC is not working in LPM3.

    - Unfortunately the P1.1 signal source can't be turned-off. We can't insert an analog switch on the P1.1 line.

  • 0 in reply to Hideaki Nambu
    TI__Expert 7555 points
    Thanks for the clarification. Hideaki.

    One quick comment- I am assuming that you have removed jumper J11 on the MSP-EXP430FR2433 to disconnect R7 and LED2 from the net. If not, please check this. The fact that there is zero current until around 1.6V makes me suspect that you are hitting a forward voltage of a diode. However, I would expect higher currents at the higher voltages, so I don't think this is the root cause- but I wanted to check nonetheless.

    Walter
  • 0 in reply to Walter Schnoor
    Mastermind 9165 points

    Walter,

    Yes. My J11 was ON. Thank you, My test result was not correct.

    I tried the test again. The result was well under 500nA across V={GND, 3.3V}.

    It means that I could not duplicate customer problem.

     Anyway I am talking to customer to about the real leakage path. 

    - - - - -

    My customer found a fault on their side. Let's close this.

    They also said many thanks. And thank you very much from me.

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