# Is it possible to construct a 6-to-64 line decoder using a 3-to-8 line decoders

#### electrogirl

Joined May 2, 2010
47
Is it possible to construct a 6-to-64 line decoder using a 3-to-8 line decoders? if it is then how?

I know how to construct a 4-to-16 line decoder using a 3-to-8 line decoders by using 2 decoders and using one input as the enable input. But this one is different because it has lots of inputs and I don't know what to do with those other inputs.

Supposedly this is the given problem: Implement F(A, B, C, D, E, F) = ∑m(1,2,5,7,10,11,13,15,22,23,24,25,30,31,32,33,54,55,56,57,61,62,63) using a) 3x8 decoder

Just give me an idea on how this is done... i'll be the one who will do the implementation thanks ^^,

#### Georacer

Joined Nov 25, 2009
5,182
The way I see it, you will need 9 3-to-8 decoders. 8 of them will work in parallel and will service the 3 LSB's and one in front of them all will take the 3 MSB's and output the correct enable signal for the appropriate decoder.

#### electrogirl

Joined May 2, 2010
47
The way I see it, you will need 9 3-to-8 decoders. 8 of them will work in parallel and will service the 3 LSB's and one in front of them all will take the 3 MSB's and output the correct enable signal for the appropriate decoder.

#### idmond

Joined Oct 5, 2010
18
Georacer is right. you can take outputs of one 3x8 decoder [Enable Decoder] as Enable Inputs for each one of the other eight decoders in such a way that only one decoder will produce its 8 combinations while the others are disabled by the Enable Decoder.

as for the 3 LSB's inputs, you can take them from any one of the 8 parallel decoders, but then you have to connect all the inputs of the other 7 parallel decoders to the one you first choose for the LSB's inputs.

here is a schematic for the 6-to-64 decoder in the attachments.

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#### Georacer

Joined Nov 25, 2009
5,182
Thankfully, there are some people that are not afraid to bust a second sweat and design a diagram for the student.
Or do they actually hurt the student by giving him ready work?

I know I don't because of the first reason, anyway...

#### iam

Joined Dec 19, 2010
1
Georacer is right. you can take outputs of one 3x8 decoder [Enable Decoder] as Enable Inputs for each one of the other eight decoders in such a way that only one decoder will produce its 8 combinations while the others are disabled by the Enable Decoder.

as for the 3 LSB's inputs, you can take them from any one of the 8 parallel decoders, but then you have to connect all the inputs of the other 7 parallel decoders to the one you first choose for the LSB's inputs.

here is a schematic for the 6-to-64 decoder in the attachments.
thnx a lot !!!!

#### beenthere

Joined Apr 20, 2004
15,819
Thankfully, there are some people that are not afraid to bust a second sweat and design a diagram for the student.
Or do they actually hurt the student by giving him ready work?
We usually insist that the student post up some work to see that the exercise is not just a straight gimmie. Very little learning takes place when someone simply obtains a complete answer

See the post from the latest OP. He gets the grade, and I suspect that idmond gets no credit for actually having done the work.

I would not particularly care to erase all such problem-solving schematics, but rather encourage everyone to recall the educational aspect and not simply hand over complete solutions on demand.