vivado HDL实现VGA显示白底黑字“FPGA”

要在VGA上显示“FPGA”字符，需要使用VHDL或Verilog编写代码来生成HDL模块，并使用Vivado工具将其综合到FPGA芯片中。以下是示例VHDL代码：

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;
use IEEE.NUMERIC_STD.ALL;

entity VGA_display is
    Port ( clk : in  STD_LOGIC;
           reset : in  STD_LOGIC;
           hsync : out  STD_LOGIC;
           vsync : out  STD_LOGIC;
           r : out  STD_LOGIC_VECTOR (3 downto 0);
           g : out  STD_LOGIC_VECTOR (3 downto 0);
           b : out  STD_LOGIC_VECTOR (3 downto 0));
end VGA_display;

architecture Behavioral of VGA_display is

    -- VGA timing parameters
    constant H_DISPLAY : integer := 640;
    constant H_FRONT_PORCH : integer := 16;
    constant H_SYNC : integer := 96;
    constant H_BACK_PORCH : integer := 48;
    constant V_DISPLAY : integer := 480;
    constant V_FRONT_PORCH : integer := 10;
    constant V_SYNC : integer := 2;
    constant V_BACK_PORCH : integer := 33;

    -- Counters
    signal hcount : integer range 0 to H_DISPLAY+H_FRONT_PORCH+H_SYNC+H_BACK_PORCH-1 := 0;
    signal vcount : integer range 0 to V_DISPLAY+V_FRONT_PORCH+V_SYNC+V_BACK_PORCH-1 := 0;

    -- VGA colors
    constant BLACK : std_logic_vector(3 downto 0) := "0000";
    constant WHITE : std_logic_vector(3 downto 0) := "1111";

    -- Display character "FPGA"
    constant F : std_logic_vector(6 downto 0) := "0111111";
    constant P : std_logic_vector(6 downto 0) := "1111001";
    constant G : std_logic_vector(6 downto 0) := "1011011";
    constant A : std_logic_vector(6 downto 0) := "1110111";

    -- Display buffer
    signal buffer : std_logic_vector(31 downto 0) := (others => '0');

begin

    process (clk, reset)
    begin
        if (reset = '1') then
            hcount <= 0;
            vcount <= 0;
            buffer <= (others => '0');
        elsif (rising_edge(clk)) then
            -- Horizontal counter
            if (hcount = H_DISPLAY+H_FRONT_PORCH+H_SYNC+H_BACK_PORCH-1) then
                hcount <= 0;
                -- Vertical counter
                if (vcount = V_DISPLAY+V_FRONT_PORCH+V_SYNC+V_BACK_PORCH-1) then
                    vcount <= 0;
                else
                    vcount <= vcount + 1;
                end if;
            else
                hcount <= hcount + 1;
            end if;
        end if;
    end process;

    -- Generate VGA signals
    hsync <= '1' when ((hcount >= H_DISPLAY+H_FRONT_PORCH) and (hcount < H_DISPLAY+H_FRONT_PORCH+H_SYNC)) else '0';
    vsync <= '1' when ((vcount >= V_DISPLAY+V_FRONT_PORCH) and (vcount < V_DISPLAY+V_FRONT_PORCH+V_SYNC)) else '0';

    -- Generate display buffer
    process (clk)
    begin
        if (rising_edge(clk)) then
            case hcount is
                when 0 to 7 =>
                    buffer <= F & BLACK & BLACK & BLACK;
                when 8 to 15 =>
                    buffer <= BLACK & F & BLACK & BLACK;
                when 16 to 23 =>
                    buffer <= BLACK & BLACK & F & BLACK;
                when 24 to 31 =>
                    buffer <= BLACK & BLACK & BLACK & F;
                when H_DISPLAY+H_FRONT_PORCH+H_SYNC to H_DISPLAY+H_FRONT_PORCH+H_SYNC+7 =>
                    buffer <= P & BLACK & BLACK & BLACK;
                when H_DISPLAY+H_FRONT_PORCH+H_SYNC+8 to H_DISPLAY+H_FRONT_PORCH+H_SYNC+15 =>
                    buffer <= BLACK & P & BLACK & BLACK;
                when H_DISPLAY+H_FRONT_PORCH+H_SYNC+16 to H_DISPLAY+H_FRONT_PORCH+H_SYNC+23 =>
                    buffer <= BLACK & BLACK & P & BLACK;
                when H_DISPLAY+H_FRONT_PORCH+H_SYNC+24 to H_DISPLAY+H_FRONT_PORCH+H_SYNC+31 =>
                    buffer <= BLACK & BLACK & BLACK & P;
                when H_DISPLAY+H_FRONT_PORCH+H_SYNC+32 to H_DISPLAY+H_FRONT_PORCH+H_SYNC+39 =>
                    buffer <= G & BLACK & BLACK & BLACK;
                when H_DISPLAY+H_FRONT_PORCH+H_SYNC+40 to H_DISPLAY+H_FRONT_PORCH+H_SYNC+47 =>
                    buffer <= BLACK & G & BLACK & BLACK;
                when H_DISPLAY+H_FRONT_PORCH+H_SYNC+48 to H_DISPLAY+H_FRONT_PORCH+H_SYNC+55 =>
                    buffer <= BLACK & BLACK & G & BLACK;
                when H_DISPLAY+H_FRONT_PORCH+H_SYNC+56 to H_DISPLAY+H_FRONT_PORCH+H_SYNC+63 =>
                    buffer <= BLACK & BLACK & BLACK & G;
                when H_DISPLAY+H_FRONT_PORCH+H_SYNC+64 to H_DISPLAY+H_FRONT_PORCH+H_SYNC+71 =>
                    buffer <= A & BLACK & BLACK & BLACK;
                when H_DISPLAY+H_FRONT_PORCH+H_SYNC+72 to H_DISPLAY+H_FRONT_PORCH+H_SYNC+79 =>
                    buffer <= BLACK & A & BLACK & BLACK;
                when H_DISPLAY+H_FRONT_PORCH+H_SYNC+80 to H_DISPLAY+H_FRONT_PORCH+H_SYNC+87 =>
                    buffer <= BLACK & BLACK & A & BLACK;
                when H_DISPLAY+H_FRONT_PORCH+H_SYNC+88 to H_DISPLAY+H_FRONT_PORCH+H_SYNC+95 =>
                    buffer <= BLACK & BLACK & BLACK & A;
                when others =>
                    buffer <= (others => '0');
            end case;
        end if;
    end process;

    -- Output VGA colors
    r <= buffer(31 downto 28);
    g <= buffer(27 downto 24);
    b <= buffer(23 downto 20);

end Behavioral;

在这个示例中，我们使用了一个计数器来控制VGA信号的生成，并使用一个缓冲区来生成要在屏幕上显示的像素数据。我们将HDL模块的输出连接到FPGA芯片的VGA引脚上。在每个时钟周期内，我们根据计数器的值来确定当前的像素所应该显示的颜色。在这个示例中，我们使用了四种颜色：黑色、白色、红色和绿色，来显示“FPGA”字符。