sel_stamp.v

可实现找钱功能的自动售邮票机

module sel_stamp(m10,m5,confirm,cancel,charge,owe_led,out_led,rst,out_coin,out_stamp,incoin1,
                 incoin10,incoin5,incount,count,clk);
input m10,m5,confirm,cancel,charge,incoin1,incoin5,incoin10,rst,clk;
output reg[1:0] out_stamp;
output reg[2:0] out_coin;
output reg[5:0] incount,count;
output reg owe_led,out_led;
        reg[2:0] state,nstate;

parameter idle=3'b0,
          start=3'b001,
          A=3'b010,
          B=3'b011,
          C=3'b100;
always@(posedge clk)
if(rst)
state<=idle;
else
state<=nstate;
 
 always@(posedge m10,posedge m5,posedge confirm,posedge cancel,posedge charge,
posedge incoin1,posedge incoin5,posedge incoin10,rst)        
          
          case(state)
              
          idle: begin
               nstate=start;
               incount=0;
               owe_led=0;
               out_led=0;
               count=0;
               out_stamp=0;
               out_coin=0;
               
           end
          
              start:begin
                  out_coin=0;
                  owe_led=1'b0;
                  out_led=1'b0;
              if(m10)
                      begin
                          nstate=A;
                          count='d10;
                      end
                       else if(m5)
                     begin
                         count='d5;
                         nstate=A;
                     end else
                     nstate=start;
                     
                 end
                  A:  if(incoin1==1)
                      begin
                       incount=incount+1;
                       if(incount<count)
                       begin
                       nstate=A;
                       owe_led=1'b1;
                   end
                       else
                       begin
                       nstate=B;
                       owe_led=1'b0;
                   end
                   end
                       else if(incoin5==1)
                       begin
                       incount=incount+5;
                       if(incount<count)
                       begin
                       nstate=A;
                       owe_led=1'b1;
                   end
                       else
                       begin
                       nstate=B;
                       owe_led=1'b0;
                   end
                   end
                       else if(incoin10==1)
                       begin
                       incount=incount+10;
                       if(incount<count)
                       begin
                       nstate=A;
                       owe_led=1'b1;
                   end
                    else
                    begin
                    nstate=B;
                    owe_led=1'b0;
                     out_led=1'b1;
                end
            end
                   else if(cancel==1)
                        nstate=C; 
                   B: begin
                       out_led=0;
                   if(confirm)
                       begin
                           if(count==4'b0101)
                           begin
                               incount=incount-5'b0101;
                               out_stamp=2'b01;
                           end
                           else if(count==10)
                            begin
                                incount=incount-5'b1010;
                                out_stamp=2'b10;
                            end
                            nstate=C;     
                        end
                        else 
                        nstate=C;
                    end
                            
                   C:begin
                       out_stamp=2'b0;
                       out_led=0;
                    if (charge)
                      begin
                          if(incount<5)
                          begin
                              out_coin=3'b001;
                              incount=incount-1;
                              if(!incount)
                                 nstate=start;
                             else
                                nstate=C;
                          end
                          else if(incount<10)
                          begin
                              out_coin=3'b010;
                              incount=incount-'d5;
                              if(!incount)
                                 nstate=start;
                             else
                                nstate=C;
                          end
                          else if(incount<=20)
                          begin
                              out_coin=3'b100;
                              incount=incount-'d10;
                              if(!incount)
                                 nstate=start;
                             else
                                nstate=C;
                          end 
                          else
                          nstate=start;
                      end 
                      else 
                      begin
                      nstate=start;
                      incount=0;
                  end
              end
                      default:nstate=start;
              endcase
      endmodule