# How do I connect a 74LS151 without using any TTL device

Hi I need you help I must connect this function
Z= X3'X2'X1 X0+X3'X2 X1'X0+X3'X2 X1 X0 in a Multiplexer the 74LS151 without using any other TTL device. I was thinking of putting in the 3 bit entry X3 , X2 , X1 so how do i put X0 and where ??? How do I connect I's to form that function, I really don´t know how to use a multiplexer i am a begginer in this.

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berkeman
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gaom84 said:
Hi I need you help I must connect this function
Z= X3'X2'X1 X0+X3'X2 X1'X0+X3'X2 X1 X0 in a Multiplexer the 74LS151 without using any other TTL device. I was thinking of putting in the 3 bit entry X3 , X2 , X1 so how do i put X0 and where ??? How do I connect I's to form that function, I really don´t know how to use a multiplexer i am a begginer in this.
Sounds like an interesting logic puzzle, but I'm not sure that I understand your notation. I'll try to re-write it using & + ~ (and, or and invert/not):

Z = (X3 & ~X2 & ~X1) + (X3 & ~X2 & X1 & ~X0) + (X3 & ~X2 & X1 & X0)

or is it:

Z = (~X3 & ~X2 & X1) + (~X3 & X2 & ~X1 & X0) + (~X3 & X2 & X1 & X0)

Which are you trying to make? Is the assumption that both the non-inverted and inverted forms of X[3:0] are available to be used as inputs, or do you have to generated the inverted forms as well somehow? If I interpreted your notation correctly, the equation can be simplified. And then look at how you can use the data inputs and data select inputs together on the multiplexer to form the equation....

This sounds like a class problem. It's not extremely complex, and can be resolved by applying a truth table to the device.

KM