- Construct a 5-to-32 line decoder with four 3-to-8 line decoder with enable and a 2-to-4 line decoder. Use block diagrams for the components, label all inputs and outputs.
- A combinational circuit is defined by the following three Boolean functions:
F 1 = ( y ′ + x ) z
F 2 = y ′ z ′ + x ′ y + y z ′
F 3 = ( x + y ) z
Design the circuit with a decoder and external gates. Draw the diagram, and label all inputs and outputs. (Hints: turn each function to sum of minterms.)
- Design an active high BCD-to-decimal decoder using the unused combinations of the BCD code as don’t-care conditions
- Construct a 16×1 multiplexer with two 8×1 and one 2×1 multiplexers. Use block diagrams and label all inputs and outputs.
- Implement a full adder with two 4×1 multiplexers. Draw the truth-table, diagram and label the inputs and outputs.
- An 8×1 multiplexer has inputs A, B, And C connected to the selection inputs S2, S1, and S0, respectively. The data inputs I0 through I7 are as follows
I1 = I2 = 0, I3 = I7 = 1; I4 = I5 = D’; and I0 = I6 = D;
Determine the Boolean function that the multiplexer implements.
- Using a case statement, write an HDL behavioral description of an eight-bit arithmetic logic unit (ALU). The circuit has a three-bit select bus (Sel), 8-bit input datapaths (A[7:0] and B[7:0]), an eight-bit output datapath (y[7:0]), and performs the arithmetic and logic operations listed below.
Sel Operation Description
000 y = 8’b0
001 y = A & B Bitwise AND
010 y = A | B Bitwise OR
011 y = A ^ B Bitwise exclusive OR
100 y = ~ A Bitwise complement
101 y = A – B Subtract
110 y = A + B Add (Assume A and B are unsigned)
111 y = 8’hFF