xilinx ise vhdl 示例代码
时间: 2023-05-13 12:03:53 浏览: 74
Xilinx ISE是一款流行的FPGA设计工具。使用ISE编写VHDL代码可以实现各种功能。以下是一些用VHDL编写的示例代码:
1. 具有时序逻辑的计数器:该计数器可以在时钟触发下递增,并在达到特定计数器时触发输出。
```vhdl
entity counter is
Port ( clk : in std_logic;
reset : in std_logic;
count : out std_logic_vector (3 downto 0));
end counter;
architecture Behavioral of counter is
signal reg_count : std_logic_vector(3 downto 0);
begin
process(clk, reset)
begin
if (reset = '1') then
reg_count <= (others => '0');
elsif (rising_edge(clk)) then
if (reg_count = "1001") then
reg_count <= (others => '0');
else
reg_count <= reg_count + 1;
end if;
end if;
end process;
count <= reg_count;
end Behavioral;
```
2. 带有并行访问的ROM:该ROM可以在指定地址位置检索数据。
```vhdl
entity rom is
Port ( addr : in std_logic_vector(5 downto 0);
q : out std_logic_vector(7 downto 0));
end rom;
architecture Behavioral of rom is
type rom_array is array(0 to 63) of std_logic_vector(7 downto 0);
constant rom_data : rom_array := (
"00000001",
"00000010",
"00000011",
...
"11111101",
"11111110",
"11111111"
);
begin
q <= rom_data(to_integer(unsigned(addr)));
end Behavioral;
```
3. 通过乘法器实现的低通滤波器:该滤波器可以通过去除高频成分来平滑输入信号。
```vhdl
entity low_pass_filter is
Port ( clk : in std_logic;
reset : in std_logic;
filter_in : in std_logic_vector(7 downto 0);
filter_out : out std_logic_vector(7 downto 0));
end low_pass_filter;
architecture Behavioral of low_pass_filter is
signal reg_x : std_logic_vector(7 downto 0);
signal reg_y : std_logic_vector(15 downto 0);
begin
process(clk, reset)
begin
if (reset = '1') then
reg_x <= (others => '0');
reg_y <= (others => '0');
elsif (rising_edge(clk)) then
reg_x <= filter_in;
reg_y <= std_logic_vector(unsigned(reg_x) * 65535 + unsigned(reg_y));
end if;
end process;
filter_out <= std_logic_vector(unsigned(reg_y) / 65535);
end Behavioral;
```
这些示例代码可以用于学习和实践VHDL设计。对于更复杂的设计,还需要使用其他工具和技术。