经典设计整理之一——————获取信号的上升沿和下降沿

川长思鸟来 2022-10-02 14:45 195阅读 0赞

有的时候需要获取信号的上升沿或下降沿，如延时消抖。在此特准备了一个简单的代码，以便以后用。

获取上升沿和下降沿代码：

1 /*********************************************************************************
     2     Company:        
     3     Engineer:            中华小虾
     4     Project Name:    
     5     Module Name:    acq_edge.v
     6     Function Description:捕捉上升沿和下降沿
     7             
     8     Revision History: 
     9             v1.0     2013.3.17      Description: Initial Release.
    10 ***********************************************************************************/
    11 
    12 module acq_edge(clk,rst_n,signal,pos_edge,neg_edge);
    13 
    14     input clk;
    15     input rst_n;
    16     input signal;
    17     output pos_edge;
    18     output neg_edge;
    19     
    20     reg [1:0] acq;
    21     
    22     always @(posedge clk or negedge rst_n)
    23     begin
    24         if(!rst_n)
    25             acq <= 0;
    26         else
    27             acq <= {acq[0],signal};
    28     end 
    29     
    30     assign pos_edge = ~acq[1] & acq[0];            //捕捉上升沿
    31     assign neg_edge = acq[1] & ~acq[0];            //捕捉下升沿
    32     
    33 endmodule

测试文件：

1 /*********************************************************************************
     2     Company:        
     3     Engineer:            中华小虾
     4     Project Name:    
     5     Module Name:    edge_tb.v
     6     Function Description:测试acq_edge.v
     7             
     8     Revision History: 
     9             v1.0     2013.3.17      Description: Initial Release.
    10 ***********************************************************************************/
    11 
    12 module edge_tb;
    13 
    14     reg     clk;
    15     reg     rst_n;
    16     reg     signal;
    17     wire     pos_edge;
    18     wire     neg_edge;
    19     
    20     acq_edge unit(
    21                         .clk(clk),
    22                         .rst_n(rst_n),
    23                         .signal(signal),
    24                         .pos_edge(pos_edge),
    25                         .neg_edge(neg_edge)
    26                     );
    27 
    28 //设置监视信号
    29     initial
    30     begin
    31         $monitor ($time,"pos_edge = %b, neg_edge = %b", pos_edge,neg_edge);
    32     end
    33                     
    34 //设置时钟
    35     initial
    36     begin
    37         clk = 0;
    38         forever #5 clk = ~clk;                //设clk为100MHz
    39     end
    40     
    41 //控制清零信号
    42     initial
    43     begin
    44         rst_n = 0;                            
    45         repeat (5) @(negedge clk);
    46         rst_n = 1;
    47     end
    48                 
    49 //施加激励信号
    50     initial
    51     begin
    52         signal = 0;
    53         repeat (10) @(negedge clk);    signal = 1;
    54         repeat (1) @(negedge clk);    signal = 0;    
    55         repeat (10) @(negedge clk);    signal = 1;
    56         repeat (10) @(negedge clk);    signal = 0;
    57         repeat (1) @(negedge clk);    signal = 1;
    58         repeat (5) @(negedge clk);    signal = 0;
    59         
    60         repeat (10) @(negedge clk);    $stop;
    61         
    62     end
    63                 
    64 endmodule

Isim仿真：

![17194340-3e3e4e7be7864670ba95f49a09bcb8e2.jpg][]

转载于:https://www.cnblogs.com/zhonghuaxiaoxia/archive/2013/03/17/2964841.html

[17194340-3e3e4e7be7864670ba95f49a09bcb8e2.jpg]: /images/20220109/b67e2749ffb3487598cd5d2191357038.png