如何在VHDL中初始化std_logic_vector?

时间:2015-05-18 09:41:18

标签: vhdl hdl xilinx-ise

我有一个std_logic_vector(4096 downto 0)信号,我想像下面那样初始化它:

architecture Behavioral of test is

    type ram_type is array(4095 downto 0) of std_logic_vector(15 downto 0);
    signal ram : ram_type;
    ram(0) := "0010000000000100";   
    ram(1) := "0001000000000101";
    ram(2) := "0011000000000110";
    ram(3) := "0111000000000001";
    ram(4) := "0000000000001100";
    ram(5) := "0000000000000011";
    ram(6) := "0000000000000000";
    ram(4095 downto 7) := (others => (others => '0'));
    begin
   "some code"
end behavioral

由于某些原因我需要用这些值初始化它(我不能将这些值分配给它,它必须初始化) 还有什么方法可以做到吗?我尝试了上面的代码,它没有工作

1 个答案:

答案 0 :(得分:4)

ram可以初始化为:

architecture Behavioral of test is
    type ram_type is array(4095 downto 0) of std_logic_vector(15 downto 0);
    signal ram : ram_type := (0 => "0010000000000100",
                              1 => "0001000000000101",
                              2 => "0011000000000110",
                              3 => "0111000000000001",
                              4 => "0000000000001100",
                              5 => "0000000000000011",
                              6 => "0000000000000000",
                              others => (others => '0'));
begin
  -- Concurrent code
end Behavioral;

但您可能需要查看具体的FPGA和工具功能,看看是否有一些特定的方法应该将初始值赋予RAM,以便综合工具可以正确映射它。