# MSB , LSB of 4 bit counter

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

1. ### Nathan Hale Thread Starter Active Member

Oct 28, 2011
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2
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
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Kinda depends on the manufacturer.

3. ### JohnInTX Moderator

Jun 26, 2012
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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
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675
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
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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
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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?