MSB , LSB of 4 bit counter

Discussion in 'General Electronics Chat' started by Nathan Hale, Dec 4, 2013.

  1. Nathan Hale

    Thread Starter Member

    Oct 28, 2011
    Hello guys! hope all is well!
    Can some one please tell me if Q3 is the MSB or LSB of a up counter? Also can you please tell me if Q0 is the MSB or LSB of a down counter. (We are taking about a 4 bit counter here.)
    Thank You
  2. shteii01

    AAC Fanatic!

    Feb 19, 2010
    Kinda depends on the manufacturer.

    Open datasheet and start reading.
  3. JohnInTX


    Jun 26, 2012
    Q3 would be the MSB of a 4 bit counter in either the up or down mode. Its weight is 2^3. Q0 would be the LSB in up or down mode with a weight of 2^0.

    The naming of the Q outputs can vary but its always in weighted order i.e. MSB->LSB is Q3->Q0, QD->QA etc.
  4. tshuck

    Well-Known Member

    Oct 18, 2012
    Despite what JohnInTX describes is the most common way (and arguably the most reasonable), there is nothing stopping a designer from labeling the outputs as banana, chicken, rock, and snorkel.

    So, read the datasheet if this is an IC, or trace the logic flow if this is a discrete implementation...
  5. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    Nothing besides decades of engineering tradition built upon centuries of mathematical progress.

    ZERO will always denote a lower quantity.

    But read the data sheet anyway. You never know what you'll find there.
  6. shteii01

    AAC Fanatic!

    Feb 19, 2010
    Funny story...

    I got old TI-55 calculator, it is from 1970s. It uses rechargeable battery pack. The pack is old and all corroded. I took it out. Now I have two wires. Red wire. Black wire. Care to guess which is positive and which is negative?