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If pins are unused, what should they be wired to? — Parallax Forums

If pins are unused, what should they be wired to?

bulkheadbulkhead Posts: 405
edited 2005-10-23 21:45 in General Discussion
If I never call "writePin()" for a certain pin, does it matter if I leave that pin connected to Vdd or Vss? or should I leave it unconnected at all? I did put a 220 ohm resistor on each pin, so does that mean it doesn't matter whether the pin is connected properly or not?

Comments

  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2005-10-23 21:45
    Hello,

    ·· This is really a matter of perspective...Some people will put pull-up resistors on all unused I/O pins to prevent oscillations that can occur when the pins are left floating.· This can cause minor current fluctuations which doesn't really affect most systems, but again, it depends on application and preference.· Others will make unused pins and output set low.· Either is fine.

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
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