题解 | #游戏机计费程序#

`timescale 1ns/1ns

module game_count
    (
		input rst_n, //异位复位信号，低电平有效
        input clk, 	//时钟信号
        input [9:0]money,
        input set,
		input boost,
		output reg[9:0]remain,
		output reg yellow,
		output reg red
    );

    always@(posedge clk, negedge rst_n) begin
        if(!rst_n) begin yellow <= 1'b0; red <= 1'b0; end
        else if(remain > 'd0 && remain < 'd10) begin yellow <= 1'b1; red <= 1'b0; end
        else if(remain == 'd0) begin yellow <= 1'b0; red <= 1'b1; end
        else begin yellow <= 1'b0; red <= 1'b0; end
    end

    always@(posedge clk, negedge rst_n) begin
        if(!rst_n) remain <= 'd0;
        else if(set) remain <= remain + money;
        else if(!boost) remain <= remain - 'd1;
        else if(boost) remain <= remain - 'd2;
    end

endmodule