vhdl二选一case
时间: 2023-09-14 19:11:51 浏览: 95
在VHDL中,二选一(mux)可以通过使用case语句来实现。以下是一个例子:
```
library ieee;
use ieee.std_logic_1164.all;
entity mux_2to1 is
port (
sel : in std_logic; -- 选择信号
in_0 : in std_logic; -- 输入0
in_1 : in std_logic; -- 输入1
out : out std_logic -- 输出
);
end entity;
architecture Behavioral of mux_2to1 is
begin
process (sel, in_0, in_1)
begin
case sel is
when '0' => out <= in_0; -- 如果sel为0,则输出in_0
when '1' => out <= in_1; -- 如果sel为1,则输出in_1
when others => out <= 'X'; -- 如果sel不为0或1,则输出未定义状态
end case;
end process;
end architecture;
```
在上面的代码中,process语句包含sel、in_0和in_1作为输入,并根据sel的值选择输出。当sel为0时,输出in_0;当sel为1时,输出in_1;否则输出未定义状态('X')。这样就实现了一个二选一(mux)电路。
相关问题
vhdl四选一数据选择器
以下是一个基于 VHDL 的 4 选 1 数据选择器的代码示例:
```
entity data_selector is
port (
data0 : in std_logic_vector(7 downto 0);
data1 : in std_logic_vector(7 downto 0);
data2 : in std_logic_vector(7 downto 0);
data3 : in std_logic_vector(7 downto 0);
select : in std_logic_vector(1 downto 0);
output : out std_logic_vector(7 downto 0)
);
end entity;
architecture Behavioral of data_selector is
begin
process (data0, data1, data2, data3, select)
begin
case select is
when "00" =>
output <= data0;
when "01" =>
output <= data1;
when "10" =>
output <= data2;
when others =>
output <= data3;
end case;
end process;
end architecture;
```
这个代码实现了一个 4 选 1 的数据选择器,它有四个输入端口 data0, data1, data2, data3,一个选择端口 select,和一个输出端口 output。当 select 等于 "00" 时,输出值为 data0;当 select 等于 "01" 时,输出值为 data1;以此类推。如果 select 输入其他值,则输出 data3。
vhdl16选一数据选择器
以下是一个简单的 16 选 1 数据选择器的 VHDL 代码示例:
```vhdl
entity data_selector is
port (
data_in : in std_logic_vector(15 downto 0);
sel : in std_logic_vector(3 downto 0);
data_out : out std_logic_vector(15 downto 0)
);
end data_selector;
architecture Behavioral of data_selector is
begin
process(data_in, sel)
begin
case sel is
when "0000" =>
data_out <= data_in(0);
when "0001" =>
data_out <= data_in(1);
when "0010" =>
data_out <= data_in(2);
when "0011" =>
data_out <= data_in(3);
when "0100" =>
data_out <= data_in(4);
when "0101" =>
data_out <= data_in(5);
when "0110" =>
data_out <= data_in(6);
when "0111" =>
data_out <= data_in(7);
when "1000" =>
data_out <= data_in(8);
when "1001" =>
data_out <= data_in(9);
when "1010" =>
data_out <= data_in(10);
when "1011" =>
data_out <= data_in(11);
when "1100" =>
data_out <= data_in(12);
when "1101" =>
data_out <= data_in(13);
when "1110" =>
data_out <= data_in(14);
when "1111" =>
data_out <= data_in(15);
when others =>
data_out <= (others => '0');
end case;
end process;
end Behavioral;
```
这个 16 选 1 数据选择器使用 4 个输入端口来选择输入数据中的一个。输入 sel 是一个 4 位二进制数,可以选择 16 个不同的输入数据。在上面的代码中,我们使用 case 语句来根据选择信号 sel 选择正确的输入数据,并将其赋值给输出 data_out。