Mt2015 q4b

• 来源：Mt2015 q4b - HDLBits

Problem Statement

Taken from 2015 midterm question 4

Circuit B can be described by the following simulation waveform: 

Implement this circuit.

Official Solution

module top_module(
    input x,
    input y,
    output z);

    // The simulation waveforms gives you a truth table:
    // y x   z
    // 0 0   1
    // 0 1   0
    // 1 0   0
    // 1 1   1   
    // Two minterms: 
    // assign z = (~x & ~y) | (x & y);

    // Or: Notice this is an XNOR.
    assign z = ~(x^y);

endmodule

My Solution

module top_module ( input x, input y, output z );

    assign z = x & y | ~x & ~y;

endmodule

Note

• 根据波形图列真值表

x	y	z
0	0	1
1	0	0
0	1	0
1	1	1
- 根据真值表列卡诺图

x/y	0	1
0	1	0
1	0	1
- 根据卡诺图可得：$z = xy + \overline{x}\overline{y}=x\bigodot y$