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MSP430F4270IDL ADC Channel 0 (Port6.0)

Kum Hoo Lee
Expert 1855 points

Hi,

I am using one ADC channel, differential pair, to do the conversion in MSP430F4270IDL. But I am seeing a sign inversion

Positive analog input -->negative counts

Negative analog input --> positive counts

 What will be the reason that I saw an inversion from the ADC?

Is there an inversion in the built in ADC?

 I saw from Errata, The interrupt delay function can result in incorrect conversion data, will it cause by this? 

Thanks for the help.

KH

  • 0
    TI__Expert 5465 points
    KH,

    I'm not exactly sure I understand what you are asking. Please correct me if my understanding is incorrect, but I will try my best to answer your questions.

    There is no inherent inversion on the SD16 module input. That is to say, if the voltage (in comparison to AVss) at the A0+ terminal is greater than the voltage at the A0- terminal, you should get a "positive value" from the module.

    Do you have some examples of what you are doing and what values you are seeing?

    Can you connect the A0- input to AVss and apply a DC value on A0+ (0.5V would be a good value) and read out the value from the converter (it should be positive)?

    Also, the errata should not be a factor in this discussion. You should be operating by default with the interrupt delay set to the fourth conversion, the point at which this errata has no effect on the results.
  • 0 in reply to Tyler Witt
    Expert 1855 points
    Hi Tyler,

    Thanks for sharing the knowledge and the suggestion given.

    Best regards,
    KH

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