题解 | #自动贩售机2#

`timescale 1ns/1ns

module seller2(
	input wire clk  ,
	input wire rst  ,
	input wire d1 ,
	input wire d2 ,
	input wire sel ,
	
	output reg out1,
	output reg out2,
	output reg out3
);
//*************code***********//
reg [2:0] money;

wire [2:0] charge;

assign charge = sel ? 5 : 3;

always@(posedge clk or negedge rst) begin
	if(!rst) begin
		money  <= '0;
		out1   <= '0;
		out2   <= '0;
		out3   <= '0;
	end
	else begin
		if (money < charge) begin
			money  <= money + {d2, d1};
			out1 <= 0;
			out2 <= 0;
			out3 <= 0;
		end
		else begin
			money  <= 0;
			if (sel)
				out2 <= 1;
			else
				out1 <= 1;
			out3 <= money - charge;
		end
	end
end

//*************code***********//
endmodule