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endmodule

//74HC148²âÊÔƽ̨´úÂë `timescale 1ns/1ns module test_HC148; reg ei; reg [7:0]i; wire [2:0]a; wire gs,eo;

HC148 u1(ei,i,a,gs,eo); initial begin ei=1; #20 ei=0;

i=8'b11111111; #20 i=8'b11111110; #20 i=8'b11111101; #20 i=8'b11111011; #20 i=8'b11110111; #20 i=8'b11101111; #20 i=8'b11011111; #20 i=8'b10111111; #20 i=8'b01111111; end endmodule

//74HC138´úÂë

module HC138(E1,E2,E3,A,Y); input E1,E2,E3; input [2:0]A; output [7:0]Y; reg [7:0]Y; integer I;

always@(E1,E2,E3,A) begin

if(E1==1||E2==1||E3==0) Y=8'b11111111; else

Y=1'b1<

//74HC138²âÊÔƽ̨´úÂë module test_HC138; reg e1,e2,e3;

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reg [2:0]a; wire [7:0]y;

HC138 u2(e1,e2,e3,a,y); initial begin a=0;

repeat(20)

#20 a=$random; end initial begin e1=1; #10 e2=1; #10 e3=0; #10 e1=0; #10 e2=0; #10 e3=1; end endmodule

//74HC153´úÂë

module HC153(S,I1,I2,E1,E2,Y1,Y2); input [1:0]S; input [3:0]I1; input [3:0]I2; input E1,E2; output Y1,Y2; reg Y1,Y2;

always@(S,I1,I2,E1,E2) begin if(E1) Y1=0; else

Y1=I1[S]; if(E2) Y2=0; else

Y2=I2[S]; end endmodule

//74HC153²âÊÔƽ̨´úÂë module test_HC153; reg [1:0]s; reg[3:0]i1;

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reg[3:0]i2; reg e1,e2; wire y1,y2;

HC153 u3(s,i1,i2,e1,e2,y1,y2); initial begin e1=1; e2=1;

#15 e1=0;e2=0; end initial begin

s=0;i1=0;i2=0;

#10 i1=4'b1001;i2=4'b1100; #10 s=1; #10 s=2; #10 s=3; end endmodule

//74HC85´úÂë

module HC85(A,B,I,Q); input [3:0]A,B; input [2:0]I; output [2:0]Q; reg [2:0]Q; always@(A,B) begin

if(A>B) Q=3'b100; else if(A

else if(I==3'b101) Q=3'b000; else if(I==0) Q=3'b101; else Q=I; end endmodule

//74HC85²âÊÔƽ̨´úÂë module test_HC85;

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reg [3:0]a,b; reg [2:0]i; wire [2:0]q;

HC85 u4(a,b,i,q); initial begin i=0; repeat(4)

#10 i=$random; end initial begin

a=3;b=1; #10

a=1;b=4; #10

a=0;b=0; #10

a=6;b=1; #10

a=5;b=9; end endmodule

//74HC283´úÂë

module HC283(CIN,A,B,COUT,S); input CIN; input [3:0]A,B; output COUT; output [3:0]S; reg COUT; reg [3:0]S;

always@(CIN,A,B) begin

{COUT,S}=CIN+A+B; end endmodule

//74HC283²âÊÔƽ̨´úÂë module test_HC283; reg cin; reg [3:0]a,b; wire cout; wire [3:0]s;

HC283 u5(cin,a,b,cout,s);

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