Decade counter

Build a decade counter that counts from 0 through 9, inclusive, with a period of 10. The reset input is synchronous, and should reset the counter to 0.

題目網站

 1 module top_module (
 2     input clk,
 3     input reset,        // Synchronous active-high reset
 4     output [3:0] q);
 5 always @(posedge clk)begin
 6     if(reset || q >= 4'd9)begin   //這裡是什麼意思?
 7             q<=4'b0;
 8         end
 9         else begin
10             q<=q+1'b1;
11         end
12     end
13 
14 endmodule

再寫：

構建一個十進位制計數器，從0-9，迴圈

對於註釋“if(reset || q >= 4'd9)begin //這裡是什麼意思?”，這裡等於是將兩種情況，一個是重置，一個是迴圈到頭，兩者一起寫了

module top_module (
    input clk,
    input reset,        // Synchronous active-high reset
    output [3:0] q);
    always@(posedge clk)begin
        if(reset)begin
           q<=0; 
        end
        else begin
            if(q==4'd9)begin
                q<=0;
            end
            else begin
                q<=q+1'b1;
            end
        end
    end
endmodule