Shop OBEX P1 Docs P2 Docs Learn Events
What to do with all those left over pins — Parallax Forums

What to do with all those left over pins

JonJonJonJon Posts: 20
edited 2005-02-09 04:23 in General Discussion
Guys,

What is one to do with all the left over port pins that are not used in an application of an sx chip.· I've noticed that I get very noisy transistions on open pins that are configured at High Z for imput but not connected.· Is there a standard parctice for these orphaned guys???· I do notice that when I configure these for output with '0' the noise seem to stop and things settle down.

Regards,

JJ

·

Comments

  • James NewtonJames Newton Posts: 329
    edited 2005-02-09 01:05
    http://www.sxlist.com/techref/logic/xtrapins.htm

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    ---
    James Newton, Host of SXList.com
    james@sxlist.com 1-619-652-0593 fax:1-208-279-8767
    SX FAQ / Code / Tutorials / Documentation:
    http://www.sxlist.com Pick faster!



  • JonJonJonJon Posts: 20
    edited 2005-02-09 01:19
    Now that is what I call an answer. Complete quick and concise!

    Thanks James!

    JJ
  • Jim G.Jim G. Posts: 27
    edited 2005-02-09 04:23
    Thanks for posting this excellent question; I will be changing my practice a little... ;-)

    When considering whether to tie a spare pin high or low, I often tie it high through a resistor, since many chip's i/o ports·can sink more current than they can source.· This way, if I need to use the pin for something later,·the "active" state is the low, high drive state.

    My $0.02.

    Jim
Sign In or Register to comment.