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AShar42
Beginner
894 Views

My code is making a random LED generator using LSFR. But, I want to turn on only one LED at a time, but my program is randomly generating 1-3 LED at a time.

module Memorygame

#(parameter BITS = 5)

(clk, rst_n, out); 

input clk;

input rst_n;

output reg [3:0] out;

reg [3:0] out_next;

integer count=0;

reg clk_1hz;

 

always @ (posedge clk) begin // slows our clock from 50mhz to 1hz 

if (count<25000000)

count = count +1; 

else begin 

clk_1hz = ~clk_1hz;

count = 0;

end 

end 

 

always @* begin // responsible for determing the blinking of the leds

  out_next = out;

   repeat(BITS) begin

out_next = {out_next[2:0],(out_next[3]^out_next[0])};

end

end

 

always @(posedge clk_1hz or negedge rst_n) begin

   if(!rst_n)

     out <= 4'h1f;

   else

     out <= out_next;

    end

endmodule

1 Reply
Abe
Valued Contributor II
52 Views

There are a couple of issues.. check out this code and try if it works.. this is the correct way to implement a LFSR.

 

`timescale 1ns/1ns module Memorygame ( input wire clk, input wire rst_n, output reg [3:0] out );   integer count; reg clk_1hz; wire lf; // linear feedback of XORed bits.   always @ (posedge clk or negedge rst_n) begin // slows our clock from 50mhz to 1hz if(!rst_n) begin count = 0; clk_1hz <= 1'b0; end else begin if (count<250000) count <= count + 1; else begin clk_1hz <= ~clk_1hz; count <= 0; end end end //always assign lf = !(out[3] ^ out[0]); always @(posedge clk_1hz or negedge rst_n) begin if(!rst_n) out <= 4'b0000; else begin out <= {out[2],out[1], out[0], lf}; end end //always

 

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