Description
Part A) Q1(70 Marks):
Decoders can be regarded as a kind of Converters.
From The truth table convert the BCD to 7 segment to specified output functions: H,T,L,K,M,L,N
a. Simplify the output function using Kmap (SOP or POS which ever is more direct).
Make sure to use the “DON’T CARE” conditions as part of map.
b. Draw a circuit for each of your simplified functions in the simulator. Attach switches
for inputs, and light bulbs for outputs ( or 7 segment led).
c. Attach led to each output of the function
BCD(8421) | OUTPUTS
DEC A B C D H I J K L M N
0 0 0 0 0 1 1 1 1 1 1 0
1 0 0 0 1 0 1 1 0 0 0 0
2 0 0 1 0 1 1 0 1 1 0 1
3 0 0 1 1 1 1 1 1 0 0 1
4 0 1 0 0 0 1 1 0 0 1 1
5 0 1 0 1 1 0 1 1 0 1 1
6 0 1 1 0 1 0 1 1 1 1 1
7 0 1 1 1 1 1 1 0 0 0 0
8 1 0 0 0 1 1 1 1 1 1 1
9 1 0 0 1 1 1 1 1 0 1 1
10 1 0 1 0 x x x x x x x
11 1 0 1 1 x x x x x x x
12 1 1 0 0 x x x x x x x
13 1 1 0 1 x x x x x x x
14 1 1 1 0 x x x x x x x
15 1 1 1 1 x x x x x x x
Part B) (130 marks)
Design a circuit which take in 2 sets of 4bits and add them together, display resulting sum value as
decimal digit(s) on 2 seven segments led. To display the binary sum (c+4bits) on 2 seven segments led
you may have to custom design a new converter, or create one using 2 adders along with gates.
Draw circuit using Logisim. Make sure to add input switch for the 4 Xi and Yi.
To get full marks your circuit must be able to display from the min to max range of adding 2 set of 4 bits.
You may use prebuilt adder from Logisim or from your prior works. You may use your BCD to 7 segment
circuit from part A or the one provided to you on Dec 3rd.
Make to show all your works for part A & B.
Submit: one document showing you derivations and one circuit file with all your circuits
Hint for part B converter: look at decay counter detection gate for the one with using adders,
And for custom design think ‘5-8’ converter: self investigate >4 literals kmap
Binary sum (c +4 bits ) BCD ( 2×4)
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