LIBRARY IEEE; USE IEEE.STD_LOGIC_1164.ALL; USE IEEE.STD_LOGIC_UNSIGNED.ALL; ENTITY counter1 IS PORT(clr,en,clk: IN STD_LOGIC; Q : OUT STD_LOGIC_VECTOR(4 DOWNTO 0)); END counter1; ARCHITECTURE count OF counter1 IS SIGNAL count: STD_LOGIC_VECTOR(3 DOWNTO 0); BEGIN PROCESS(clk,clr) BEGIN IF(clr='1') THEN count<=(others=>'0'); ELSIF(rising_edge(clk)) THEN IF(en='1') THEN IF(count="1011") THEN count="0000"; ELSE count=count+'1'; END IF; END IF; END PROCESS; Q<=count; END counter1;找出里面的错误并更改
时间: 2024-02-14 13:13:34 浏览: 18
在代码中 `count` 是一个四位向量,但在 `count<= '0000'` 中只有三个零。应该将其修改为 `count<=(others=>'0')`。另外,在时序逻辑中,不能将多个敏感信号(如 `clk` 和 `clr`)放在同一个敏感列表中,应该将其分开。修改后的代码如下:
```
LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;
USE IEEE.STD_LOGIC_UNSIGNED.ALL;
ENTITY counter1 IS
PORT(
clr, en, clk: IN STD_LOGIC;
Q: OUT STD_LOGIC_VECTOR(4 DOWNTO 0)
);
END counter1;
ARCHITECTURE count OF counter1 IS
SIGNAL count: STD_LOGIC_VECTOR(4 DOWNTO 0);
BEGIN
PROCESS(clk)
BEGIN
IF(clr = '1') THEN
count <= (OTHERS => '0');
ELSIF(rising_edge(clk)) THEN
IF(en = '1') THEN
IF(count = "1011") THEN
count <= "0000";
ELSE
count <= count + '1';
END IF;
END IF;
END IF;
END PROCESS;
Q <= count;
END count;
```