问(vcom-1339)案例陈述的选择仅涵盖10个案例中的6个。

EN

library ieee;
use IEEE.std_logic_1164.all;
use ieee.numeric_std.all;

entity FSMM is
port (CLK : in std_logic; --Clock, active high
 RSTn : in std_logic; --Async. Reset, active low
 CoinIn : in std_logic_vector (1 downto 0); --Which coin was inserted
 gum : out std_logic; --Is Soda dispensed ?
 CoinOut : out std_logic_vector (1 downto 0) --Which coin is dispensed?
 );

end entity;

architecture behavior of FSMM is
-- add your code here
type state_type is (idle, --start state/reset
 put_money, --waiting to enter money
 in_5c,in_10c,in_15c,in_20c,in_25c,in_30c,in_35c, --represent the current sum of money after returning change
 gum_out --dispence soda can.
 ); --type of state machine.
signal current_s,next_s: state_type; --current and next state declaration.

begin

process(CLK,RSTn)
begin
 if(RSTn = '0') then
 current_s <= idle; --defualt state is on RESET
 elsif(clk'event and clk = '1') then
 current_s <= next_s;
 end if;
end process;
--------------------
--FSM process:
process(current_s,CoinIn)
begin
case current_s is
 when idle => --state reset or idle
 gum <= '0';
 CoinOut <= "00";
 next_s <= put_money;
 ------------------------------------------------------
 when put_money => --wait for money to be entered
 if(CoinIn = "00")then
 gum <= '0';
 CoinOut <= "00";
 next_s <= put_money;
 elsif(CoinIn = "01")then --insert 5$
 gum <= '0';
 CoinOut <= "00";
 next_s <= in_5c;
elsif(CoinIn = "10")then --insert 10$
 gum <= '0';
 CoinOut <= "00";
 next_s <= in_10c;
elsif(CoinIn = "11")then --insert 25$
 gum <= '0';
 CoinOut <= "00";
 next_s <= in_25c;
 end if;
 ------------------------------------------------------
 when in_5c => 
 if(CoinIn = "00") then--stay on the same state
 gum <= '0';
 CoinOut <= "00";
 next_s <= in_5c;
 elsif(CoinIn = "01") then--inserted another 1$
 gum <= '0';
 CoinOut <= "00";
 next_s <= in_10c;
 elsif(CoinIn = "01") then--inserted another 2$
 gum <= '0';
 CoinOut <= "00";
 next_s <= in_15c;
 elsif(CoinIn = "01") then--inserted another 2$
 gum <= '0';
 CoinOut <= "00";
 next_s <= in_20c;
 elsif(CoinIn = "01") then--inserted another 2$
 gum <= '0';
 CoinOut <= "00";
 next_s <= in_25c;
 elsif(CoinIn = "01") then--inserted another 2$
 gum <= '0';
 CoinOut <= "00";
 next_s <= in_30c;
 elsif(CoinIn = "01") then--inserted another 2$
 gum <= '0';
 CoinOut <= "00";
 next_s <= in_35c;
 elsif(CoinIn = "01") then--inserted another 2$
 gum <= '0';
 CoinOut <= "00";
 next_s <= gum_out;
 end if;
------------------------------------------------------
 when in_10c => 
 if(CoinIn = "00") then--stay on the same state
 gum <= '0';
 CoinOut <= "00";
 next_s <= in_10c;
 elsif(CoinIn = "10") then--inserted another 1$
 gum <= '0';
 CoinOut <= "00";
 next_s <= in_20c;
 elsif(CoinIn = "10") then--inserted another 1$
 gum <= '0';
 CoinOut <= "00";
 next_s <= in_30c;
 elsif(CoinIn = "10") then--inserted another 1$
 gum <= '0';
 CoinOut <= "00";
 next_s <= gum_out;
 end if;
------------------------------------------------------
 when in_25c => 
 if(CoinIn = "00") then--stay on the same state
 gum <= '0';
 CoinOut <= "00";
 next_s <= in_25c;
 elsif(CoinIn = "01") then--inserted another 1$
 gum <= '0';
 CoinOut <= "00";
 next_s <= in_30c;
 elsif(CoinIn = "01") then--inserted another 1$
 gum <= '0';
 CoinOut <= "00";
 next_s <= in_35c;
 elsif(CoinIn = "01") then--inserted another 1$
 gum <= '0';
 CoinOut <= "00";
 next_s <= gum_out;
 end if;
 ------------------------------------------------------
 when gum_out =>
 gum <= '1';
 CoinOut <= "00";
 next_s <= put_money; 

end case;
end process;
end behavior;