一个简单的状态机程序，感觉仿真波形有点问题呢
--moore状态机--**************库定义、 包定义********************
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;
--**************实体定义********************
entity moore IS
port(
clk,ready,read_write : in std_logic;
reset : in std_logic;--复位输入
oe,we : out std_logic
);
end moore;
--**************构造体定义********************
architecture state_machine of moore is
type state_type is(idle,decision,read,write);--自定义信号类型
signal present_state,next_state:state_type;
begin
state_comb : process(present_state,ready,read_write)
begin
case present_state is
when idle=> --空闲状态
oe<='1';
we<='1';
if ready='1' then
next_state<=decision;
else
next_state<=idle;
end if;
when decision=> --判定状态
oe<='0';
we<='0';
if read_write='1' then
next_state<=read;
else
next_state<=write;
end if;
when read=> --读状态
oe<='1';
we<='0';
if ready='1' then
next_state<=idle;
else
next_state<=read;
end if;
when write=> --写状态
oe<='0';
we<='1';
if ready='1' then
next_state<=idle;
else
next_state<=write;
end if;
end case;
end process state_comb;
state_clocked: process(clk,reset)
begin
if(reset = '0') then
present_state<=idle;
elsif rising_edge(clk) then
present_state<=next_state;
end if;
end process;
end state_machine;下面是仿真前加入的信号，给reset两个复位信号，read_write一个低电平信号：
仿真结果：
前部分展开图：
比较疑惑的问题是，为何第二个reset信号完之后，后面就没有波形了，按住程序来说在还没到read_write的低电平来之前应该还重复前面的波形啊？？？
顶一下。
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