（1）自加LED显示代码 本模块用于检测或者验证LED的电路，以及性能，一般人都会用到。
//`timescale 1ns/1ns module led_addr_display#( parameter LED_WIDTH = 8)( //global clock input clk, input rst_n, //user led output output reg [LED_WIDTH-1:0] led_data); //----------------------------------- localparam DELAY_TOP = 24‘hff_ffff;reg [23:0] delay_cnt;always@(posedge clk or negedge rst_n)begin if(!rst_n) delay_cnt <= 0; else if(delay_cnt < DELAY_TOP) delay_cnt <= delay_cnt + 1‘b1; else delay_cnt <= 0;endwire delay_done = (delay_cnt == DELAY_TOP) ? 1‘b1 : 1‘b0; //----------------------------------- always@(posedge clk or negedge rst_n)begin if(!rst_n) led_data <= 0; else if(delay_done) led_data <= led_data + 1‘b1; else led_data <= led_data;endendmodule（2）LED外部输入显示
本模块用于外部数据/信号的数据，便于直观的显示结果，方便校验。
`timescale 1ns/1nsmodule led_input_display#( parameter LED_WIDTH = 8)( //global clock input clk, input rst_n, //user interface for led input led_en, input [LED_WIDTH-1:0] led_value, output reg [LED_WIDTH-1:0] led_data); //-------------------------------------- always@(posedge clk or negedge rst_n)begin if(!rst_n) led_data <= {LED_WIDTH{1‘b0}}; else if(led_en) led_data <= led_value; else led_data <= led_data;endendmodule（3）LED移位流水灯显示
本模块只是一个花样的功能，当然写好一个流水的，也许有很多很多的方法，比如状态机，Case， if else语句，到底哪种方法好与不好，其实事到如今，你应该思考：如何设计电路才是最完美的！例如：
`timescale 1ns/1nsmodule led_water_display#( parameter LED_WIDTH = 8)( //global clock input clk, input rst_n, //user led output output reg [LED_WIDTH-1:0] led_data); //----------------------------------- localparam DELAY_TOP = 24‘hff_ffff;//localparam DELAY_TOP = 24‘hf;reg [23:0] delay_cnt;always@(posedge clk or negedge rst_n)begin if(!rst_n) delay_cnt <= 0; else if(delay_cnt < DELAY_TOP) delay_cnt <= delay_cnt + 1‘b1; else delay_cnt <= 0;endwire delay_done = (delay_cnt == DELAY_TOP) ? 1‘b1 : 1‘b0;//-----------------------------------reg [2:0] led_cnt; //led countreg left_done, right_done; //led water done edgealways@(posedge clk or negedge rst_n)begin if(!rst_n) begin led_data <= 1; led_cnt <= 0; {left_done, right_done} <= 2‘b10; end else if(delay_done) begin led_cnt <= (led_cnt < LED_WIDTH - 2‘d2) ? led_cnt + 1‘b1 : 3‘d0; //water edge exchange if(led_cnt == LED_WIDTH - 2‘d2) {left_done, right_done} <= ~{left_done, right_done}; else {left_done, right_done} <= {left_done, right_done}; //water led exchange case({left_done, right_done}) 2‘b10: led_data <= (led_data << 1); 2‘b01: led_data <= (led_data >> 1); default:; endcase end else begin led_data <= led_data; led_cnt <= led_cnt; {left_done, right_done} <= {left_done, right_done}; endend原文：http://www.cnblogs.com/ffpp/p/4222173.html