|
- module hc139( //74HC139 二组 二线到四线译码器 VCC:Pin16 GND:Pin8
- input aA, //Pin2
- input bA, //Pin3
- input eA, //Pin1
- input aB, //Pin14
- input bB, //Pin13
- input eB, //Pin15
- output [3:0] yA, //Pin7~Pin4
- output [3:0] yB //Pin9~Pin12
- );
- reg [3:0] a;
- reg [3:0] b;
- assign yA = a;
- assign yB = b;
- always @(*) begin
- if(eA) begin
- a = 4'hF;
- end else begin
- a = ~(4'h1 << {bA,aA});
- end
- end
- always @(*) begin
- if(eB) begin
- b = 4'hF;
- end else begin
- b = ~(4'h1 << {bB,aB});
- end
- end
- endmodule
- module main(
- input clk,
- output reg led
- );
- wire [3:0] a;
- wire [3:0] b;
- hc139 U1(
- .aA(1),
- .bA(1),
- .eA(0),
- .aB(0),
- .bB(1),
- .eB(0),
- .yA(a),
- .yB(b),
- );
- always @(posedge clk) begin
- if(a == 4'b0111 && b == 4'b1011) begin
- led <= 0;
- end else begin
- led <= 1;
- end
- end
- endmodule
复制代码 |
|