case (currentstate)Р S1: money_out= 3'b001; //状态1退币0.5Р S2: money_out= 3'b010; //状态2退币1Р S3: money_out= 3'b011; //状态3退币1.5Р S4: money_out= 3'b100; //状态4退币2Р default: money_out= 3'b000;Р endcaseР end Р else money_out= 3'b000; РendmoduleР4.5.2 测试程序Рmodule softdrink_testbench;Рreg rst, clk; Р reg check;Р reg [1:0] money_in; Р wire charge; Р wire drink_out; Р wire [2:0] money_out;Р softdrinkFSM m1(clk,rst,check,money_in,charge,drink_out,money_out);Р always #25 clk=~clk;РinitialР beginР clk=1;Р rst=0;Р check=0;Р money_in=2'b00;Р #25 rst=1;Р #25 rst=0;Р //投3个1元,共3元Р #50 rst=1;Р #50 money_in=2'b10;Р #50 money_in=2'b10;Р #50 money_in=2'b10;Р #50 money_in<=2'b00;Р #50 rst<=0;Р check<=0;Р Р//投1个5角和2个1元,共2.5元Р#50 rst=1;Р#50 money_in=2'b01;?Р#50 money_in=2'b10;Р#50 money_in=2'b10;Р#50 money_in<=2'b00;