5v to 3.3V bus translation and vice versa

Discussion in 'The Projects Forum' started by majsta, Aug 31, 2011.

  1. majsta

    Thread Starter New Member

    Aug 31, 2011
    Basic idea is to connect mc68000 to cyclone II, 5V device to 3.3V.

    There is something wrong with quickswich devices. As I know MC68000 cant
    support 3.3V (some versions can but mine just cant). When i use quickswich
    any type i only get 5V to 3.3V translation and no vice versa. I need to use
    dual voltage level translator with auto sensing. Even sn74lvc8t245 have direction control and txs0108e have auto sensing.
    For last two days I m reading about Pericom articles and those articles are
    just like IDT have for quickswich part. Devices are working from higher to
    lower and I m thinking that I just cant use those devices. For some devices
    who work with 5V can drive lower voltage levels that is ok but on my
    situation is not. For example PI5CX and PI3CX series are only related to 5V
    to 3.3V translation no bidirectional and then i need to use bus enable
    input like on most devices. From A to B bus or from B to A bus, that is not
    practical. Also some Pericom devices PI74LVC4245 who have two voltage on
    each bus side but no auto sensing again I need to set direction sides. I
    just dont know, as much i m reading only thing is txs0108e that I m using
    on design right now. Also using Pericom or IDT devices we can use pull up
    resistor connected to higher power source. I just dont know....
  2. SgtWookie


    Jul 17, 2007
    A quick Google search for "logic level translator" will result in millions of hits.

    I'm on my way out the door so don't really have time to help you at the moment, but have a look at this:

  3. majsta

    Thread Starter New Member

    Aug 31, 2011
    Yes I have this document allready. But thanks.
  4. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
  5. ToBeFrank

    New Member

    Nov 18, 2010
    I've used the txb0108. It works great.

    If you need any sort of speed, don't follow this Sparkfun guide.