首页module shiftreg_nb_V05 (output reg A,input E, clk, rst); reg B, C, D; always @ (posedge clk, posedge rst) begin if (rst == 1'b1) begin A <= 0; B <= 0; C <= 0; D <= 0; end else begin A <= B; // D <= E; B <= C; // C <= D; C <= D; // B <= C; D <= E; // A <= B; end end endmodule

module shiftreg_nb_V05 (output reg A,input E, clk, rst); reg B, C, D; always @ (posedge clk, posedge rst) begin if (rst == 1'b1) begin A <= 0; B <= 0; C <= 0; D <= 0; end else begin A <= B; // D <= E; B <= C; // C <= D; C <= D; // B <= C; D <= E; // A <= B; end end endmodule

时间: 2024-04-26 14:26:37 浏览: 139

xapp199 module testbench

writing efficient testbenches `timescale 1 ns/1 ps module testbench; reg clock; reg load; reg reset; wire [4:0] shiftreg; reg [4:0] data; reg [1:0] sel; shift_reg u1 ( .clock (clock), .load (load), .reset (reset), .shiftreg (shiftreg), .data (data), .sel (sel)); initial begin clock = 0; forever #50 clock = ~clock; end initial begin reset = 1; data = 5'b00000; load = 0; sel = 2'b00; #200 reset = 0; load = 1; #200 data = 5'b00001; #100 sel = 2'b01; load = 0; #200 sel = 2'b10; #1000 $stop; // #1000 $finish; end endmodule

这是一个Verilog HDL写的模块，实现了一个四位移位寄存器，输入为 E，时钟为 clk，复位为 rst，输出为 A。在时钟上升沿或者复位信号为高电平时，寄存器的状态会发生改变。具体来说，在复位信号为高电平时，四位寄存器的值都会被清空为0；在时钟上升沿时，寄存器内的值会按照如下规则更新： A <= B, B <= C, C <= D, D <= E。其中，符号“<=”表示将右侧的值赋给左侧的变量。

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