Circuit to Convert Binary to BCD

Thread Starter

Diamond

Joined Feb 2, 2009
4
Hello Guys,

I need to design a logic circuit that converts a four digit binary input to equivalent Binary Coded Decimal value. The circuit should have four input bits, but five output bit. For eg: input 1001 (decimal 9) the suggested output will be 0 1001 (the BCD value 09) for an input 1010 (decimal 10) the output should be 1 0000 (the BCD value 10).

I need to create truth table and boolean expression for this.

Please help out.

Thanks
 

beenthere

Joined Apr 20, 2004
15,808
Take a look at a BCD counter like a 74162. You shouldn't have any trouble with a truth table.
 

beenthere

Joined Apr 20, 2004
15,808
If you make a vertical column with all the binary values from 0000 to 1111, and another column with the corresponding BCD values, it will show you the circuit output for each binary input.
 

Thread Starter

Diamond

Joined Feb 2, 2009
4
Binary Values BCD Values (5 output)
0000.......................00
0001.......................01
0010.......................02
0011.......................03
0100.......................04
0101.......................05
0110.......................06
0111.......................07
1000.......................08
1001.......................09 (output in binary 0 1001)
1010.......................10 (output in binary 1 0000)

Ok This can be the truth table and this is the requirement. But how to develop circuit which which give me five output for four input bit with BCD values.

I hope you have understood my requirement.
 

beenthere

Joined Apr 20, 2004
15,808
Do you only have to go to 10d? 1111 is Fh, or 15d.

Do you have any experience working with logic elements - AND gate, OR gates? You might notice that when the value is above 8 AND 2 OR 3 OR 4, etc, then BCD bit 4 sets.
 

veritas

Joined Feb 7, 2008
167
You will actually end up with 5 truth tables. Each table will correspond to one of your five output bits, and each will have four inputs.

Go from there.
 

Thread Starter

Diamond

Joined Feb 2, 2009
4
See this is the actual question. I dont have practical experience of GATES except theory.

Design a logic circuit that converts a four digit binary input to equivalent Binary Coded Decimal value. You need to first create the truth table (please note this circuit should have four input bits, but five output bits; for example, for an input 1001 (decimal 9) the suggested output will be 0 1001 (the BCD value 0 9); and for an input 1010 (decimal 10) the suggested output should be 1 0000 (the BCD value 1 0 )). After creating the truth table design the Boolean expressions for each of the five output bits. Draw the resulting circuit diagram using AND – OR – NOT gates.

Please guide.
 

Skeebopstop

Joined Jan 9, 2009
358
your truth table is not that it is:

inputs 1-4 : outputs 1-5
0001 00001 (notice just same thing)
0010 00010
....
1010 10000
1011 10001
1100 10010
1101 10011
1110 10100
 

patel

Joined Apr 11, 2009
1
Binary Values BCD Values (5 output)
0000.......................00
0001.......................01
0010.......................02
0011.......................03
0100.......................04
0101.......................05
0110.......................06
0111.......................07
1000.......................08
1001.......................09 (output in binary 0 1001)
1010.......................10 (output in binary 1 0000)

Ok This can be the truth table and this is the requirement. But how to develop circuit which which give me five output for four input bit with BCD values.

I hope you have understood my requirement
 
Top