「HDLBits题解」Counters

本专栏的目的是分享可以通过HDLBits仿真的Verilog代码 以提供参考 各位可同时参考我的代码和官方题解代码 或许会有所收益

---

题目链接：Count15 - HDLBits

module top_module (
    input clk,
    input reset,      // Synchronous active-high reset
    output [3:0] q
); 
    always @(posedge clk) begin
        if (reset) q <= 0 ; 
        else q <= q == 15 ? 0 : q + 1 ; 
    end

endmodule

---

题目链接：Count10 - HDLBits

module top_module (
    input clk,
    input reset,      // Synchronous active-high reset
    output [3:0] q
); 
    always @(posedge clk) begin
        if (reset) q <= 0 ; 
        else q <= q == 9 ? 0 : q + 1 ; 
    end

endmodule

---

题目链接：Count1to10 - HDLBits

module top_module (
    input clk,
    input reset,      // Synchronous active-high reset
    output reg [3:0] q
); 
    always @(posedge clk) begin
        if (reset) q <= 1 ; 
        else q <= q == 10 ? 1 : q + 1 ; 
    end

endmodule

---

题目链接：Countslow - HDLBits

module top_module (
    input clk,
    input slowena,
    input reset,
    output reg [3:0] q
);
    always @(posedge clk) begin
        if (reset) q <= 0 ; 
        else if (slowena) q <= q == 9 ? 0 : q + 1 ; 
        else q <= q ; 
    end

endmodule

---

题目链接：Exams/ece241 2014 q7a - HDLBits

module top_module (
    input clk,
    input reset,
    input enable,
    output reg [3:0] Q,
    output c_enable,
    output c_load,
    output [3:0] c_d
); 
    reg [3:0] cnt_4o ;

    always @(posedge clk) begin
        if (reset) Q <= 1 ; 
        else if (enable) Q <= Q == 12 ? 1 : Q + 1 ;
        else Q <= Q ; 
    end

    assign c_enable = enable ; 
    assign c_load = reset | (enable && Q == 12) ; 
    assign c_d = c_load ? 1 : 0 ; 

    count4 the_counter (clk, c_enable, c_load, c_d, cnt_4o);

endmodule

---

题目链接：Exams/ece241 2014 q7b - HDLBits

module top_module (
    input clk,
    input reset,
    output OneHertz,
    output [2:0] c_enable
); 
    reg [3:0] q0, q1, q2 ;

    bcdcount counter0 (clk, reset, c_enable[0], q0);
    bcdcount counter1 (clk, reset, c_enable[1], q1);
    bcdcount counter2 (clk, reset, c_enable[2], q2);

    assign c_enable = {q0 == 9 & q1 == 9, q0 == 9, 1'b1}; 
    assign OneHertz = q2 == 9 & q1 == 9 & q0 == 9 ; 

endmodule

---

题目链接：Countbcd - HDLBits

module top_module (
    input clk,
    input reset,   // Synchronous active-high reset
    output [3:1] ena,
    output reg [15:0] q
);
    always @ (*) begin 
        if (q[3:0] == 9 && q[7:4] == 9 && q[11:8] == 9) ena = 7 ; 
        else if (q[3:0] == 9 && q[7:4] == 9) ena = 3 ; 
        else if (q[3:0] == 9) ena = 1 ; 
        else ena = 0 ;
    end

    sub_cnt u1(clk, reset, 1'b1, q[3:0]) ;
    sub_cnt u2(clk, reset, ena[1], q[7:4]) ;
    sub_cnt u3(clk, reset, ena[2], q[11:8]) ;
    sub_cnt u4(clk, reset, ena[3], q[15:12]) ;

endmodule 
       
module sub_cnt (
    input clk,
    input reset,      // Synchronous active-high reset
    input enable, 
    output reg [3:0] q
); 
    always @(posedge clk) begin
        if (reset) q <= 0 ; 
        else if (enable) q <= q == 9 ? 0 : q + 1 ; 
        else q <= q ; 
    end

endmodule

---

题目链接：Count clock - HDLBits

module top_module(
    input clk,
    input reset,
    input ena,
    output reg pm,
    output reg [7:0] hh,
    output reg [7:0] mm,
    output reg [7:0] ss
); 
    wire [2:0] enable ; 

    assign enable = {mm == 8'h59 & ss == 8'h59 & ena, ss == 8'h59 & ena, ena} ; 

    cnt60 uss(clk, reset, enable[0], ss) ; 
    cnt60 umm(clk, reset, enable[1], mm) ; 

    always @(posedge clk) begin
        if (reset) begin 
            hh <= 8'h12 ; 
            pm <= 0 ; 
        end
        else 
            if (enable[2]) 
                if (hh == 8'h12) hh <= 8'h1 ; 
                else if (hh == 8'h11) begin 
                    pm <= ~pm ; 
                    hh[3:0] <= hh[3:0] + 1'h1 ; 
                end
                else 
                    if (hh[3:0] == 4'h9) begin 
                        hh[3:0] <= 4'h0 ; 
                        hh[7:4] <= hh[7:4] + 1'h1 ; 
                    end
                    else 
                        hh[3:0] <= hh[3:0] + 1'h1 ; 
            else 
                hh <= hh ;
    end
endmodule

module cnt60(
    input clk, 
    input reset, 
    input ena, 
    output reg [7:0] q 
);
    always @(posedge clk) begin
        if (reset) q <= 8'h0 ; 
        else 
            if (ena) 
                if (q[3:0] == 4'h9) 
                    if 
                        (q[7:4] == 4'h5) q <= 8'h0 ; 
                    else begin 
                        q[7:4] <= q[7:4] + 1'h1 ; 
                        q[3:0] <= 4'h0 ; 
                    end
                else 
                    q[3:0] <= q[3:0] + 1'h1 ; 
            else 
                q <= q ; 
    end
endmodule