用VHDL实现3S计数
时间: 2024-02-20 16:56:04 浏览: 19
以下是一个简单的 VHDL 实现 3S 计数器的例子:
```vhdl
library ieee;
use ieee.std_logic_1164.all;
entity counter_3s is
port (
clk : in std_logic;
rst : in std_logic;
count : out std_logic_vector(1 downto 0)
);
end entity counter_3s;
architecture behavioral of counter_3s is
signal s_count : std_logic_vector(1 downto 0);
begin
process (clk, rst)
begin
if (rst = '1') then
s_count <= "00";
elsif (rising_edge(clk)) then
case s_count is
when "00" =>
s_count <= "01";
when "01" =>
s_count <= "10";
when "10" =>
s_count <= "11";
when others =>
s_count <= "00";
end case;
end if;
end process;
count <= s_count;
end architecture behavioral;
```
上面的代码中,使用 `std_logic_vector` 类型的 `s_count` 信号来存储计数器的值,初始值为 "00"。在时钟上升沿的时候,根据当前值更新计数器的值,当计数器的值为 "11" 的时候,将计数器重置为 "00"。计数器的重置信号通过 `rst` 输入给出。计数器的当前值通过 `count` 输出。