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morpeh89
Associate III
November 17, 2010
Question

GPIO input/output modes - what's the difference?

  • November 17, 2010
  • 4 replies
  • 774 views
Posted on November 17, 2010 at 08:37

GPIO input/output modes - what's the difference?

    This topic has been closed for replies.

    4 replies

    Andrew Neil
    Super User
    May 17, 2011
    Posted on May 17, 2011 at 14:15

    See also: 

    http://www.8052.com/forumchat/read/142019

    A complex system that works is invariably found to have evolved from a simple system that worked.A complex system designed from scratch never works and cannot be patched up to make it work.
    Andrew Neil
    Super User
    May 17, 2011
    Posted on May 17, 2011 at 14:15

    ''physics, such as resistors/transistors in schematics, is not very interesting now''

     

    Unfortunately, those are precisely the things that are key to understanding this!

    This is one of the key differences between embedded development - especially small microcontroller embedded development - and, say, PC development.

    Do you understand what ''Pull-Up'', ''Pull-Down'', ''Push-Pull'' and ''Open Drain'' mean in general terms?

    These are very widespread and general terms - not at all specific to ST or the STM32.

    http://en.wikipedia.org/wiki/Pull-up_resistor

    http://en.wikipedia.org/wiki/Push-pull_output

    http://en.wikipedia.org/wiki/Open_drain

      (equivalent to ''Open Collector'')

    A complex system that works is invariably found to have evolved from a simple system that worked.A complex system designed from scratch never works and cannot be patched up to make it work.
    morpeh89
    morpeh89Author
    Associate III
    May 17, 2011
    Posted on May 17, 2011 at 14:15

    OK, thanks.

    I guessed, that studying is inevitable :)

    Andrew Neil
    Super User
    May 17, 2011
    Posted on May 17, 2011 at 14:15

    ''studying is inevitable''

     

    Yes, of course - if you want (or need) to do it yourself.

    But if you don't have the expertise, and are not interested in gaining it, then you can always hire someone to do it for you:

    http://www.st.com/internet/mcu/design_contacts/design_consultants.jsp

    A complex system that works is invariably found to have evolved from a simple system that worked.A complex system designed from scratch never works and cannot be patched up to make it work.