# BCD to Binary using logic work

Discussion in 'Homework Help' started by Forza_Inter, Nov 14, 2010.

1. ### Forza_Inter Thread Starter New Member

Nov 14, 2010
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First of all, I'm asked to design a 4-bit calculator that accepts tow inputs which are in BCD and I have to convert them to Binary, so when i use the truth table the inputs and outputs will be identical because it is a 4-bit calculator.

should I get the logic diagram for BCD-to-Binary?,because the BCD and Binary numbers are the same in the digits for example 0001 in Binary is the as 0001 in BCD which is 1

Also,in logic work I used the ic 7447 to show the number in 7-segment as u can see here ( of course u should have logic work installed to open the following file)
but it doesn't work I dont know why
sorry for that but I'm really really really confused
thank you

2. ### beenthere Retired Moderator

Apr 20, 2004
15,815
290
If you are supposed to do the arithmetic unctions in binary, then you will have to convert coming and going, so to speak.

I might remind you that 99 in BCD is not the same value in binary. Just as a hint, an input of 15 should become 1111 in binary.

Not everybody has Logic Work.

3. ### Forza_Inter Thread Starter New Member

Nov 14, 2010
5
0
thank your for the fast response.
but i'm working on a 4-bit calculator with tow inputs and every inputs is 4-bits( for example 5+5 or 9+3 but I can't calculate 11+2 with the 4-bits calculator because 11 is more than 4 bits in BCD but the answer will be more than 4-bits for 9+3 which is ok)
,so I dont think that I can use the number 99 as an input which is more than 4 bits, am I right?
, so If I wanna convert from BCD to Binary I have to make a truth table with four inputs,but how many outputs?

4. ### Forza_Inter Thread Starter New Member

Nov 14, 2010
5
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bump
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Feb 5, 2010
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6. ### Forza_Inter Thread Starter New Member

Nov 14, 2010
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thx
I wanna convert from BCD to Binary I have to make a truth table with four inputs,but how many outputs?

7. ### beenthere Retired Moderator

Apr 20, 2004
15,815
290
BCD stands for Binary Coded Decimal. Notice the Binary part?

BDC goes from 0 - 9 using 4 bits, while the 4 bits in straight binary go from 0 - 15.

Nov 14, 2010
5
0