原创 状态机

我看了好几天这个状态机，总是不能达到我的要求100MHZ，放几天，要用状态机的时候在看看！

第一个程序：VHDL设计MOORE型有限状态机时速度问题的探讨

第二个程序：LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;
USE IEEE.STD_LOGIC_UNSIGNED.ALL;
USE IEEE.STD_LOGIC_ARITH.ALL;

ENTITY moo IS
PORT(clk:IN STD_LOGIC;
     ready:IN STD_LOGIC;
     we,oe:OUT STD_LOGIC;
     read_write:IN STD_LOGIC
);
END moo;

ARCHITECTURE behavioul OF moo IS
TYPE state_type IS(idle,decision,write1,read1);
SIGNAL present_state,next_state:state_type;

BEGIN

state_cmd:PROCESS(clk,present_state,ready,read_write)
BEGIN

     CASE present_state IS
          WHEN idle=>oe<='0';we<='0';
               IF ready='1'THEN
                  next_state<=decision;
               ELSE
                  next_state<=idle;
               END IF;
          WHEN decision=>oe<='0';we<='0';
                IF read_write='1'THEN
                   next_state<=read1;
                ELSE
                   next_state<=write1;
                END IF;
          WHEN read1=>oe<='1';we<='0';
                IF ready='1'THEN
                   next_state<=idle;
                ELSE
                   next_state<=read1;
                END IF;
          WHEN write1=>oe<='0';we<='1';
                IF ready='1'THEN
                   next_state<=idle;
                ELSE
                   next_state<=write1;
                END IF;
      END CASE;

END PROCESS state_cmd;

state:PROCESS(clk)
BEGIN
      IF clk'EVENT AND clk='1' THEN
         present_state<=next_state;
      END IF;
END PROCESS state;

END behavioul;

当我的周期是10NS的时候输出没有