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MSP430G2755: Unused GPIO Behavior in User’s Guide and Datasheet

Mark Swanson
Expert 3520 points
Part Number: MSP430G2755

Hi,

The datasheet for the MSP430G2755, table ‘Active Mode Supply Current Into VCC Excluding External Current’, Note (1) says all inputs are tied to 0V or VCC.

The user’s guide for the MSP430G2755, ‘Connection of Unused Pins’ indicate the Potential for port pins is Open.

1. Does the datasheet note mean all GPIO are externally tied to VCC or 0V?

2. If so, does the user’s guide need to be changed to reflect the recommended potential tied to either 0V or VCC externally?

Thank you for the help!

Best Regards,

Mark-

  • 0
    TI__Guru 61901 points

    Hi Mark,

    The datasheet is showing that for the Active mode supply current measurements, all the inputs are either tied to GND or VCC.  This is how this is tested in the factory during probe and test.  The reason is it does not require the device to be programmed with any code that would normally set the GPIO pins as described in the user's guide since after reset the GPIO pins are always inputs and can be connected to GND or VCC during test. This makes the testing time quicker.

    Now for a user's application, as described in the user's guide, it is highly recommended to set all unused GPIO pins as outputs and typically driven low with code, although you could drive them high too.  It doesn't really matter since you shouldn't connect anything to these pins (other circuits, VCC, GND, etc.).

    Here is the recommendation straight from the user's guide:

  • 0 in reply to Dennis Lehman
    TI__Expert 3520 points
    Hi Dennis,

    Thank you for the fast response and thorough explanation for the reason behind the minor differences between the datasheet note and user's guide recommendations.

    Best Regards,

    Mark-

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