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mehmet.karakaya
mehmet.karakaya
Associate III
September 7, 2010
Question

how to interface 3V3 pins with 5 V logic ?

  • September 7, 2010
  • 4 replies
  • 807 views
Posted on September 07, 2010 at 09:44

how to interface 3V3 pins with 5 V logic ?

    This topic has been closed for replies.

    4 replies

    Tesla DeLorean
    Tesla DeLorean
    Guru
    May 17, 2011
    Posted on May 17, 2011 at 14:05

    It's a universal topic, try Googling.

    Depends on the type of logic you are interfacing to (VOL/VOH/VIL/VIH), you can add buffering logic, or resistor networks, or use open-collector outputs and pull ups. Some of the STM32 pins are 5V tolerant, check the TRM.

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    Andrew Neil
    Andrew Neil
    Super User
    May 17, 2011
    Posted on May 17, 2011 at 14:05

    As clive1 says, a direct connection may be acceptable - see the datasheets of all devices concerned.

    In extremis, specific logic-level translator chips are available.

    Here's a couple of App Notes from NXP which might be helpful: 

    http://ics.nxp.com/support/documents/interface/pdf/an10441.pdf

    http://ics.nxp.com/support/documents/interface/pdf/an97055.pdf

    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
    Andrew Neil
    Super User
    May 17, 2011
    Posted on May 17, 2011 at 14:05

    As clive1 says, a direct connection may be acceptable - see the datasheets of all devices concerned.

    In extremis, specific logic-level translator chips are available.

    Here's a couple of App Notes from NXP which might be helpful: 

    http://ics.nxp.com/support/documents/interface/pdf/an10441.pdf

    http://ics.nxp.com/support/documents/interface/pdf/an97055.pdf

    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
    Andrew Neil
    Super User
    May 17, 2011
    Posted on May 17, 2011 at 14:06

    ... as Texas Instruments calls them:

    http://focus.ti.com/lit/ml/scyb018d/scyb018d.pdf

    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.
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