-- Moore State Machine with explicit state encoding
-- dowload from: www.fpga.com.cn & www.pld.com.cn
library ieee;
use ieee.std_logic_1164.all;
entity moore2 is port(
clk, rst: in std_logic;
id: in std_logic_vector(3 downto 0);
y: out std_logic_vector(1 downto 0));
end moore2;
architecture archmoore2 of moore2 is
signal state: std_logic_vector(2 downto 0);
-- State assignment is such that 2 LSBs are outputs
constant state0: std_logic_vector(2 downto 0) := "000";
constant state1: std_logic_vector(2 downto 0) := "010";
constant state2: std_logic_vector(2 downto 0) := "011";
constant state3: std_logic_vector(2 downto 0) := "110";
constant state4: std_logic_vector(2 downto 0) := "111";
begin
moore: process (clk, rst)
begin
if rst='1' then
state <= state0;
elsif (clk'event and clk='1') then
case state is
when state0 =>
if id = x"3" then
state <= state1;
else
state <= state0;
end if;
when state1 =>
state <= state2;
when state2 =>
if id = x"7" then
state <= state3;
else
state <= state2;
end if;
when state3 =>
if id < x"7" then
state <= state0;
elsif id = x"9" then
state <= state4;
else
state <= state3;
end if;
when state4 =>
if id = x"b" then
state <= state0;
else
state <= state4;
end if;
when others =>
state <= state0;
end case;
end if;
end process;
--assign state outputs (equal to state std_logics)
y <= state(1 downto 0);
end archmoore2;