• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Subscribers 31 subscribers
  • Views 344 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Original question:

ULN2803 voltage level clarification

TM4C1294NCPDT: Unused Pins of TIVA

HARANATH VASAM1
Intellectual 300 points
Part Number: TM4C1294NCPDT

We are using TIVA TM4C1294NCPDT in one of our new design. There are few unused pins in my schematic. What should we do with unused pins? Shall we keep them unconnected. Is there any document which tells about what to do with unused pins?

Thanks in advance.

HARANATH

  • 0
    TI__Guru**** 191486 points

    Hi,

      Please go to section 26.2 Connections for Unused Signals in the TM4C1294NCPDT datasheet for recommendation on unused pins.

  • 0
    Guru 117855 points

    Greetings,

    Vendor's Charles provides his usual sound answer - and indeed - just as he states - the detail you seek IS w/in the MCU Manual.

    That said - my small Tech Firm finds often that such recommendations - while technically 'correct' - fail to properly anticipate, 'Real-World Design Considerations!'

    You may consider:

    • While you (appear - at this moment) 'Not to require those pins - is that 'guaranteed to hold true - into the immediate, even distant future?   What then?
    • Anything which, 'Reduces your board's, 'Ongoing Capabilities' - should be very critically evaluated.     Has the MCU manual's advice, provided that?
    • 'Board Spins' cause delay, add cost, and are often, 'Created under duress and/or haste' - thus often prove flawed - demanding  (yet another) board spin!

    Thus my group prefers to route those (currently & potentially) 'unused pins' to a, 'Header/Connector - installed at/around board edge.'    In this manner - you may easily 'expand the capability of your board' - as/if (most often 'when') needed.    Thus SAVING a 'Board Spin.'

    The MCU Manual presents guidelines - some believe - 'too heavily' weighted upon the 'Tech!'     Yet - Electronics IS a business - and 'Saving Needless Costs & Delays' - argues against (anything) which negatively  impacts your design's 'On-Going' Capability...    (you may configure those 'unused, but now header resident pins' as 'inputs w/weak-pull-up' or 'outputs set to 2mA, max,' & driven low.)

  • 0 in reply to Charles Tsai
    Intellectual 300 points

    Thanks a lot for quick reply.

  • 0 in reply to HARANATH VASAM1
    Guru 117855 points

    Cb1 - or staffer - slowly raises pistol to cb1's head...    Business case (well detailed) is ignored - somehow that's NOT the best path to Success!

    On occasion - simply 'being here' - makes (very) little Sense...    (Staff just noted - poster's 'board vendor' lick his/her lips - ALWAYS MORE GPIO are NEEDED!)