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vcc?

damiondamion Posts: 39
edited 2005-12-01 16:30 in General Discussion
Hello,hello. I'm pretty new in this universe and I'm just wondering what vcc is? Is it the same as vdd? I'm assuming it wouldn't be labled differently if it was but anyway any help would be great.


Post Edited By Moderator (Chris Savage (Parallax)) : 11/24/2005 6:14:30 AM GMT

Comments

  • Buck RogersBuck Rogers Posts: 2,190
    edited 2005-11-24 05:10
    Hello from Buck Rogers
    Would you believe yes? It took me a lot of work to realize that they are indeed the same thing. They just refer to two seperate but related forms of logic. Vcc happens to be for TTL logic. Vdd is typically for CMOS logic. Sometimes the families happen to be running under the same voltage levels, and in this case don't worry. yeah.gif

    But things get crazy when you need to connect circuit elements that are based around those two different families, and the CMOS one happens to be running around a different level, say the Vdd is at 3-15 volts, and the TTL one happens to be Vcc at 5volts or so, which is normal. The companies that I buy compnents from, sell hardware which can handle translations between those.turn.gif

    And did I mention this is also supposed to be fun?


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  • ShortShort Posts: 26
    edited 2005-11-28 02:22
    ···· VCC· = + 5

    ···· VDD ·= + PART SUPPLY

    ···· VEE·· = - PART SUPPLY

    ·····VSS· =·· GROUND


    Short
    ·
  • Dave PatonDave Paton Posts: 285
    edited 2005-11-28 15:05
    To get a little more specific, the Vxx voltages are related to the transistors that make up the logic circuits:

    Vcc = Vcollector
    Vee = Vemitter
    Vdd =Vdrain
    Vss = Vsource

    If you think of normal chip outputs, Vcc and Vdd are generally +, and Vee and Vss are generally - (unless you're in ECL or something equally oddball), it just depends on if it's an old TTL or a newer CMOS part. They're used interchangably a lot now, which annoys some of us who know the difference. wink.gif

    -dave

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  • David BDavid B Posts: 592
    edited 2005-11-28 16:18
    When I'm hooking stuff up to my Parallax proto-board, I always have to stop and think which of VDD or VSS is +5 and ground.

    They may be useful terms to describe the chip internals, but for interfacing by the average public, wouldn't +5 and gnd be better?

    David
  • cbmeekscbmeeks Posts: 634
    edited 2005-11-29 14:07
    David B said...
    When I'm hooking stuff up to my Parallax proto-board, I always have to stop and think which of VDD or VSS is +5 and ground.

    They may be useful terms to describe the chip internals, but for interfacing by the average public, wouldn't +5 and gnd be better?

    David

    Maybe you could remember that "VSS" stands for "Voltage Stepping Stone" and Stepping Stones are usually on the ground.

    lol

    cbmeeks

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  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2005-12-01 16:30
    Anything that jogs your memory will help.

    DC belong together as in AC or DC voltage. So they are the same

    S can be considered 'soil' or 'safe'. Both associate with ground.

    I still remember ROY G. BIV for the spectrum from high school [noparse][[/noparse]1965].

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