题解 | #游戏机计费程序#
游戏机计费程序
https://www.nowcoder.com/practice/50188fb7e23b4eee86f8c463c8284f5e
充钱的一分钟应该扣钱，而且要分情况讨论，与当前状态和boost都有关，代码如下：
`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
);
reg [1:0] cstate,nstate;
parameter s0 = 2'b00,s1 = 2'b01, s2 = 2'b10;
always@(posedge clk or negedge rst_n)begin
if(!rst_n)begin
cstate <= s1;
end
else begin
cstate <= nstate;
end
end
always@(*)begin
if(!rst_n)begin
nstate <= s1;
end
else begin
case(cstate)
s1:begin
if(boost == 1'b1)
nstate <= s2;
end
s2:begin
if(boost == 'b0)
nstate <= s1;
end
endcase
end
end
always@(posedge clk or negedge rst_n)begin
if(!rst_n)begin
remain <= 'd0;
end
else begin
case(boost)
'd0:begin
if(remain > 'd0)begin
if(set == 'b1)
remain <= remain + money -'d1;
else
remain <= remain - 'd1;
end
else begin
if(set == 'b1)
remain <= remain + money;
else
remain <= remain;
end
end
'd1:begin
if(cstate == s1)begin
if(remain > 'd0)begin
if(set == 'b1)
remain <= remain + money -'d2;
else
remain <= remain - 'd2;
end
else begin
if(set == 'b1)
remain <= remain + money;
else
remain <= remain;
end
end
else if(cstate == s2)begin
if(remain > 'd1)begin
if(set == 'b1)
remain <= remain + money -'d2;
else
remain <= remain - 'd2;
end
else begin
if(set == 'b1)
remain <= remain + money;
else
remain <= remain;
end
end
end
endcase
end
end
always@(posedge clk or negedge rst_n)begin
if(!rst_n)begin
yellow <= 'd0;
red <= 'd0;
end
else begin
if(remain <= 'd0)begin
red <= 1'b1;
yellow <= 1'b0;
end
else if(remain < 'd10)begin
red <= 'd0;
yellow <= 'd1;
end
else begin
red <= 'd0;
yellow <= 'd0;
end
end
end
endmodule
