题解 | #自动贩售机1#

`timescale 1ns/1ns module seller1( input wire clk , input wire rst , input wire d1 , input wire d2 , input wire d3 ,

output reg out1,
output reg [1:0]out2

); //**code//

reg [2:0] cnt1;
reg [1:0] cnt2;
reg cnt3;

always@(posedge clk or negedge rst)
    begin
        if(!rst)
            begin
                cnt1<=0;
                cnt2<=0;
                cnt3<=0;
            end
        else
            begin
                if(d1)
                    cnt1<=cnt1+1;
                if(d2)
                    cnt2<=cnt2+1;
                if(d3)
                    cnt3<=cnt3+1;
                
                if(money >= 3) //如果用out1的话会迟1个clk
                    begin
                       cnt1<=0;
                       cnt2<=0;
                       cnt3<=0; 
                    end
            end
    end

wire [3:0] money;
assign money = cnt1+{cnt2,1'b0}+{cnt3,2'b0};

always@(posedge clk or negedge rst)
    begin
        if(!rst)
            begin
                out1<=0;
                out2<=0;
            end
        else
            begin
                if(money >= 3)
                    begin
                        out1<=1;
                        out2<=money-3;
                    end
                else
                    begin
                        out1<=0;
                        out2<=0;
                    end
            end
    end

//**code// endmodule