Fpga ram乒乓操作vhdl代码

以下是一个简单的FPGA RAM乒乓操作的VHDL代码示例：

library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;

entity ram_ping_pong is
    port (
        clk: in std_logic;
        wren: in std_logic;
        ren: in std_logic;
        addr: in unsigned(7 downto 0);
        data_in: in unsigned(7 downto 0);
        data_out: out unsigned(7 downto 0)
    );
end entity ram_ping_pong;

architecture Behavioral of ram_ping_pong is

    signal ram: unsigned(7 downto 0) := (others => '0');
    signal ping_pong: std_logic := '0';

begin

    process(clk)
    begin
        if rising_edge(clk) then
            if ping_pong = '0' then
                if wren = '1' then
                    ram(to_integer(addr)) <= data_in;
                end if;
                if ren = '1' then
                    data_out <= ram(to_integer(addr));
                end if;
                ping_pong <= '1';
            else
                if wren = '1' then
                    ram(to_integer(addr) + 128) <= data_in;
                end if;
                if ren = '1' then
                    data_out <= ram(to_integer(addr) + 128);
                end if;
                ping_pong <= '0';
            end if;
        end if;
    end process;

end architecture Behavioral;

该代码实现了一个具有单个端口的RAM，该端口可在时钟上升沿时进行读写操作。它使用一个名为`ping_pong`的信号来切换RAM的两个不同位置，以实现乒乓操作。在`ping_pong`等于`0`时，RAM的地址范围是`0`到`127`，在`ping_pong`等于`1`时，RAM的地址范围是`128`到`255`。在写入时，将数据写入到地址和`ping_pong`的值加上对应的128。在读取时，从地址和`ping_pong`的值加上对应的128处读取数据。