简单的axi lite奴隶应用

时间:2015-12-08 16:44:49

标签: vhdl vivado zynq

我正在使用Vivado 2015.3和Zybo板,我正在尝试实现一个非常简单的AXI lite IP,它从PS接收一个字符并发回相同的值+1。

我刚刚从planahead转换为生成的IP文件的vhdl文件非常简单(在我看来),现在我找不到任何有用的教程。

我的问题是在2个生成的vhdl文件(my_ip_0_v1_0_S00_AXI和my_ip_0_v1_0)内部应该添加" + 1"?

谢谢:)

my_ip_0_v1_0_S00_AXI.vhd:

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

entity my_ip_0_v1_0_S00_AXI is
generic (
    -- Users to add parameters here

    -- User parameters ends
    -- Do not modify the parameters beyond this line

    -- Width of S_AXI data bus
    C_S_AXI_DATA_WIDTH  : integer   := 32;
    -- Width of S_AXI address bus
    C_S_AXI_ADDR_WIDTH  : integer   := 4
);
port (
    -- Users to add ports here

    -- User ports ends
    -- Do not modify the ports beyond this line

    -- Global Clock Signal
    S_AXI_ACLK  : in std_logic;
    -- Global Reset Signal. This Signal is Active LOW
    S_AXI_ARESETN   : in std_logic;
    -- Write address (issued by master, acceped by Slave)
    S_AXI_AWADDR    : in std_logic_vector(C_S_AXI_ADDR_WIDTH-1 downto 0);
    -- Write channel Protection type. This signal indicates the
        -- privilege and security level of the transaction, and whether
        -- the transaction is a data access or an instruction access.
    S_AXI_AWPROT    : in std_logic_vector(2 downto 0);
    -- Write address valid. This signal indicates that the master signaling
        -- valid write address and control information.
    S_AXI_AWVALID   : in std_logic;
    -- Write address ready. This signal indicates that the slave is ready
        -- to accept an address and associated control signals.
    S_AXI_AWREADY   : out std_logic;
    -- Write data (issued by master, acceped by Slave) 
    S_AXI_WDATA : in std_logic_vector(C_S_AXI_DATA_WIDTH-1 downto 0);
    -- Write strobes. This signal indicates which byte lanes hold
        -- valid data. There is one write strobe bit for each eight
        -- bits of the write data bus.    
    S_AXI_WSTRB : in std_logic_vector((C_S_AXI_DATA_WIDTH/8)-1 downto 0);
    -- Write valid. This signal indicates that valid write
        -- data and strobes are available.
    S_AXI_WVALID    : in std_logic;
    -- Write ready. This signal indicates that the slave
        -- can accept the write data.
    S_AXI_WREADY    : out std_logic;
    -- Write response. This signal indicates the status
        -- of the write transaction.
    S_AXI_BRESP : out std_logic_vector(1 downto 0);
    -- Write response valid. This signal indicates that the channel
        -- is signaling a valid write response.
    S_AXI_BVALID    : out std_logic;
    -- Response ready. This signal indicates that the master
        -- can accept a write response.
    S_AXI_BREADY    : in std_logic;
    -- Read address (issued by master, acceped by Slave)
    S_AXI_ARADDR    : in std_logic_vector(C_S_AXI_ADDR_WIDTH-1 downto 0);
    -- Protection type. This signal indicates the privilege
        -- and security level of the transaction, and whether the
        -- transaction is a data access or an instruction access.
    S_AXI_ARPROT    : in std_logic_vector(2 downto 0);
    -- Read address valid. This signal indicates that the channel
        -- is signaling valid read address and control information.
    S_AXI_ARVALID   : in std_logic;
    -- Read address ready. This signal indicates that the slave is
        -- ready to accept an address and associated control signals.
    S_AXI_ARREADY   : out std_logic;
    -- Read data (issued by slave)
    S_AXI_RDATA : out std_logic_vector(C_S_AXI_DATA_WIDTH-1 downto 0);
    -- Read response. This signal indicates the status of the
        -- read transfer.
    S_AXI_RRESP : out std_logic_vector(1 downto 0);
    -- Read valid. This signal indicates that the channel is
        -- signaling the required read data.
    S_AXI_RVALID    : out std_logic;
    -- Read ready. This signal indicates that the master can
        -- accept the read data and response information.
    S_AXI_RREADY    : in std_logic
);
end my_ip_0_v1_0_S00_AXI;

architecture arch_imp of my_ip_0_v1_0_S00_AXI is

-- AXI4LITE signals
signal axi_awaddr   : std_logic_vector(C_S_AXI_ADDR_WIDTH-1 downto 0);
signal axi_awready  : std_logic;
signal axi_wready   : std_logic;
signal axi_bresp    : std_logic_vector(1 downto 0);
signal axi_bvalid   : std_logic;
signal axi_araddr   : std_logic_vector(C_S_AXI_ADDR_WIDTH-1 downto 0);
signal axi_arready  : std_logic;
signal axi_rdata    : std_logic_vector(C_S_AXI_DATA_WIDTH-1 downto 0);
signal axi_rresp    : std_logic_vector(1 downto 0);
signal axi_rvalid   : std_logic;

-- Example-specific design signals
-- local parameter for addressing 32 bit / 64 bit C_S_AXI_DATA_WIDTH
-- ADDR_LSB is used for addressing 32/64 bit registers/memories
-- ADDR_LSB = 2 for 32 bits (n downto 2)
-- ADDR_LSB = 3 for 64 bits (n downto 3)
constant ADDR_LSB  : integer := (C_S_AXI_DATA_WIDTH/32)+ 1;
constant OPT_MEM_ADDR_BITS : integer := 1;
------------------------------------------------
---- Signals for user logic register space example
--------------------------------------------------
---- Number of Slave Registers 4
signal slv_reg0 :std_logic_vector(C_S_AXI_DATA_WIDTH-1 downto 0);
signal slv_reg1 :std_logic_vector(C_S_AXI_DATA_WIDTH-1 downto 0);
signal slv_reg2 :std_logic_vector(C_S_AXI_DATA_WIDTH-1 downto 0);
signal slv_reg3 :std_logic_vector(C_S_AXI_DATA_WIDTH-1 downto 0);
signal slv_reg_rden : std_logic;
signal slv_reg_wren : std_logic;
signal reg_data_out :std_logic_vector(C_S_AXI_DATA_WIDTH-1 downto 0);
signal byte_index   : integer;

begin
-- I/O Connections assignments

S_AXI_AWREADY   <= axi_awready;
S_AXI_WREADY    <= axi_wready;
S_AXI_BRESP <= axi_bresp;
S_AXI_BVALID    <= axi_bvalid;
S_AXI_ARREADY   <= axi_arready;
S_AXI_RDATA <= axi_rdata;
S_AXI_RRESP <= axi_rresp;
S_AXI_RVALID    <= axi_rvalid;
-- Implement axi_awready generation
-- axi_awready is asserted for one S_AXI_ACLK clock cycle when both
-- S_AXI_AWVALID and S_AXI_WVALID are asserted. axi_awready is
-- de-asserted when reset is low.

process (S_AXI_ACLK)
begin
  if rising_edge(S_AXI_ACLK) then 
    if S_AXI_ARESETN = '0' then
      axi_awready <= '0';
    else
      if (axi_awready = '0' and S_AXI_AWVALID = '1' and S_AXI_WVALID = '1')         then
        -- slave is ready to accept write address when
        -- there is a valid write address and write data
        -- on the write address and data bus. This design 
        -- expects no outstanding transactions. 
        axi_awready <= '1';
      else
        axi_awready <= '0';
      end if;
    end if;
  end if;
end process;

-- Implement axi_awaddr latching
-- This process is used to latch the address when both 
-- S_AXI_AWVALID and S_AXI_WVALID are valid. 

process (S_AXI_ACLK)
begin
  if rising_edge(S_AXI_ACLK) then 
    if S_AXI_ARESETN = '0' then
      axi_awaddr <= (others => '0');
    else
      if (axi_awready = '0' and S_AXI_AWVALID = '1' and S_AXI_WVALID = '1') then
        -- Write Address latching
        axi_awaddr <= S_AXI_AWADDR;
      end if;
    end if;
  end if;                   
end process; 

-- Implement axi_wready generation
-- axi_wready is asserted for one S_AXI_ACLK clock cycle when both
-- S_AXI_AWVALID and S_AXI_WVALID are asserted. axi_wready is 
-- de-asserted when reset is low. 

process (S_AXI_ACLK)
begin
  if rising_edge(S_AXI_ACLK) then 
    if S_AXI_ARESETN = '0' then
      axi_wready <= '0';
    else
      if (axi_wready = '0' and S_AXI_WVALID = '1' and S_AXI_AWVALID = '1') then
          -- slave is ready to accept write data when 
          -- there is a valid write address and write data
          -- on the write address and data bus. This design 
          -- expects no outstanding transactions.           
          axi_wready <= '1';
      else
        axi_wready <= '0';
      end if;
    end if;
  end if;
end process; 

-- Implement memory mapped register select and write logic generation
-- The write data is accepted and written to memory mapped registers when
-- axi_awready, S_AXI_WVALID, axi_wready and S_AXI_WVALID are asserted. Write strobes are used to
-- select byte enables of slave registers while writing.
-- These registers are cleared when reset (active low) is applied.
-- Slave register write enable is asserted when valid address and data are available
-- and the slave is ready to accept the write address and write data.
slv_reg_wren <= axi_wready and S_AXI_WVALID and axi_awready and S_AXI_AWVALID ;

process (S_AXI_ACLK)
variable loc_addr :std_logic_vector(OPT_MEM_ADDR_BITS downto 0); 
begin
  if rising_edge(S_AXI_ACLK) then 
    if S_AXI_ARESETN = '0' then
      slv_reg0 <= (others => '0');
      slv_reg1 <= (others => '0');
      slv_reg2 <= (others => '0');
      slv_reg3 <= (others => '0');
    else
      loc_addr := axi_awaddr(ADDR_LSB + OPT_MEM_ADDR_BITS downto ADDR_LSB);
      if (slv_reg_wren = '1') then
        case loc_addr is
          when b"00" =>
            for byte_index in 0 to (C_S_AXI_DATA_WIDTH/8-1) loop
              if ( S_AXI_WSTRB(byte_index) = '1' ) then
                -- Respective byte enables are asserted as per write strobes                   
                -- slave registor 0
                slv_reg0(byte_index*8+7 downto byte_index*8) <= S_AXI_WDATA(byte_index*8+7 downto byte_index*8);
              end if;
            end loop;
          when b"01" =>
            for byte_index in 0 to (C_S_AXI_DATA_WIDTH/8-1) loop
              if ( S_AXI_WSTRB(byte_index) = '1' ) then
                -- Respective byte enables are asserted as per write strobes                   
                -- slave registor 1
                slv_reg1(byte_index*8+7 downto byte_index*8) <= S_AXI_WDATA(byte_index*8+7 downto byte_index*8);
              end if;
            end loop;
          when b"10" =>
            for byte_index in 0 to (C_S_AXI_DATA_WIDTH/8-1) loop
              if ( S_AXI_WSTRB(byte_index) = '1' ) then
                -- Respective byte enables are asserted as per write strobes                   
                -- slave registor 2
                slv_reg2(byte_index*8+7 downto byte_index*8) <= S_AXI_WDATA(byte_index*8+7 downto byte_index*8);
              end if;
            end loop;
          when b"11" =>
            for byte_index in 0 to (C_S_AXI_DATA_WIDTH/8-1) loop
              if ( S_AXI_WSTRB(byte_index) = '1' ) then
                -- Respective byte enables are asserted as per write strobes                   
                -- slave registor 3
                slv_reg3(byte_index*8+7 downto byte_index*8) <= S_AXI_WDATA(byte_index*8+7 downto byte_index*8);
              end if;
            end loop;
          when others =>
            slv_reg0 <= slv_reg0;
            slv_reg1 <= slv_reg1;
            slv_reg2 <= slv_reg2;
            slv_reg3 <= slv_reg3;
        end case;
      end if;
    end if;
  end if;                   
end process; 

-- Implement write response logic generation
-- The write response and response valid signals are asserted by the slave 
-- when axi_wready, S_AXI_WVALID, axi_wready and S_AXI_WVALID are asserted.  
-- This marks the acceptance of address and indicates the status of 
-- write transaction.

process (S_AXI_ACLK)
begin
  if rising_edge(S_AXI_ACLK) then 
    if S_AXI_ARESETN = '0' then
      axi_bvalid  <= '0';
      axi_bresp   <= "00"; --need to work more on the responses
    else
      if (axi_awready = '1' and S_AXI_AWVALID = '1' and axi_wready = '1' and S_AXI_WVALID = '1' and axi_bvalid = '0'  ) then
        axi_bvalid <= '1';
        axi_bresp  <= "00"; 
      elsif (S_AXI_BREADY = '1' and axi_bvalid = '1') then   --check if bready is asserted while bvalid is high)
        axi_bvalid <= '0';                                 -- (there is a possibility that bready is always asserted high)
      end if;
    end if;
  end if;                   
end process; 

-- Implement axi_arready generation
-- axi_arready is asserted for one S_AXI_ACLK clock cycle when
-- S_AXI_ARVALID is asserted. axi_awready is 
-- de-asserted when reset (active low) is asserted. 
-- The read address is also latched when S_AXI_ARVALID is 
-- asserted. axi_araddr is reset to zero on reset assertion.

process (S_AXI_ACLK)
begin
  if rising_edge(S_AXI_ACLK) then 
    if S_AXI_ARESETN = '0' then
      axi_arready <= '0';
      axi_araddr  <= (others => '1');
    else
      if (axi_arready = '0' and S_AXI_ARVALID = '1') then
        -- indicates that the slave has acceped the valid read address
        axi_arready <= '1';
        -- Read Address latching 
        axi_araddr  <= S_AXI_ARADDR;           
      else
        axi_arready <= '0';
      end if;
    end if;
  end if;                   
end process; 

-- Implement axi_arvalid generation
-- axi_rvalid is asserted for one S_AXI_ACLK clock cycle when both 
-- S_AXI_ARVALID and axi_arready are asserted. The slave registers 
-- data are available on the axi_rdata bus at this instance. The 
-- assertion of axi_rvalid marks the validity of read data on the 
-- bus and axi_rresp indicates the status of read transaction.axi_rvalid 
-- is deasserted on reset (active low). axi_rresp and axi_rdata are 
-- cleared to zero on reset (active low).  
process (S_AXI_ACLK)
begin
  if rising_edge(S_AXI_ACLK) then
    if S_AXI_ARESETN = '0' then
      axi_rvalid <= '0';
      axi_rresp  <= "00";
    else
      if (axi_arready = '1' and S_AXI_ARVALID = '1' and axi_rvalid = '0') then
        -- Valid read data is available at the read data bus
        axi_rvalid <= '1';
        axi_rresp  <= "00"; -- 'OKAY' response
      elsif (axi_rvalid = '1' and S_AXI_RREADY = '1') then
        -- Read data is accepted by the master
        axi_rvalid <= '0';
      end if;            
    end if;
  end if;
end process;

-- Implement memory mapped register select and read logic generation
-- Slave register read enable is asserted when valid address is available
-- and the slave is ready to accept the read address.
slv_reg_rden <= axi_arready and S_AXI_ARVALID and (not axi_rvalid) ;

process (slv_reg0, slv_reg1, slv_reg2, slv_reg3, axi_araddr, S_AXI_ARESETN, slv_reg_rden)
variable loc_addr :std_logic_vector(OPT_MEM_ADDR_BITS downto 0);
begin
    -- Address decoding for reading registers
    loc_addr := axi_araddr(ADDR_LSB + OPT_MEM_ADDR_BITS downto ADDR_LSB);
    case loc_addr is
      when b"00" =>
        reg_data_out <= slv_reg0;
      when b"01" =>
        reg_data_out <= slv_reg1;
      when b"10" =>
        reg_data_out <= slv_reg2;
      when b"11" =>
        reg_data_out <= slv_reg3;
      when others =>
        reg_data_out  <= (others => '0');
    end case;
end process; 

-- Output register or memory read data
process( S_AXI_ACLK ) is
begin
  if (rising_edge (S_AXI_ACLK)) then
    if ( S_AXI_ARESETN = '0' ) then
      axi_rdata  <= (others => '0');
    else
      if (slv_reg_rden = '1') then
        -- When there is a valid read address (S_AXI_ARVALID) with 
        -- acceptance of read address by the slave (axi_arready), 
        -- output the read dada 
        -- Read address mux
          axi_rdata <= reg_data_out;     -- register read data
      end if;   
    end if;
  end if;
end process;


-- Add user logic here

-- User logic ends

end arch_imp;

my_ip_0_v1_0.vhd:

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

entity my_ip_0_v1_0 is
generic (
    -- Users to add parameters here

    -- User parameters ends
    -- Do not modify the parameters beyond this line


    -- Parameters of Axi Slave Bus Interface S00_AXI
    C_S00_AXI_DATA_WIDTH    : integer   := 32;
    C_S00_AXI_ADDR_WIDTH    : integer   := 4
);
port (
    -- Users to add ports here

    -- User ports ends
    -- Do not modify the ports beyond this line


    -- Ports of Axi Slave Bus Interface S00_AXI
    s00_axi_aclk    : in std_logic;
    s00_axi_aresetn : in std_logic;
    s00_axi_awaddr  : in std_logic_vector(C_S00_AXI_ADDR_WIDTH-1 downto 0);
    s00_axi_awprot  : in std_logic_vector(2 downto 0);
    s00_axi_awvalid : in std_logic;
    s00_axi_awready : out std_logic;
    s00_axi_wdata   : in std_logic_vector(C_S00_AXI_DATA_WIDTH-1 downto 0);
    s00_axi_wstrb   : in std_logic_vector((C_S00_AXI_DATA_WIDTH/8)-1 downto 0);
    s00_axi_wvalid  : in std_logic;
    s00_axi_wready  : out std_logic;
    s00_axi_bresp   : out std_logic_vector(1 downto 0);
    s00_axi_bvalid  : out std_logic;
    s00_axi_bready  : in std_logic;
    s00_axi_araddr  : in std_logic_vector(C_S00_AXI_ADDR_WIDTH-1 downto 0);
    s00_axi_arprot  : in std_logic_vector(2 downto 0);
    s00_axi_arvalid : in std_logic;
    s00_axi_arready : out std_logic;
    s00_axi_rdata   : out std_logic_vector(C_S00_AXI_DATA_WIDTH-1 downto 0);
    s00_axi_rresp   : out std_logic_vector(1 downto 0);
    s00_axi_rvalid  : out std_logic;
    s00_axi_rready  : in std_logic
);
end my_ip_0_v1_0;

architecture arch_imp of my_ip_0_v1_0 is

-- component declaration
component my_ip_0_v1_0_S00_AXI is
    generic (
    C_S_AXI_DATA_WIDTH  : integer   := 32;
    C_S_AXI_ADDR_WIDTH  : integer   := 4
    );
    port (
    S_AXI_ACLK  : in std_logic;
    S_AXI_ARESETN   : in std_logic;
    S_AXI_AWADDR    : in std_logic_vector(C_S_AXI_ADDR_WIDTH-1 downto 0);
    S_AXI_AWPROT    : in std_logic_vector(2 downto 0);
    S_AXI_AWVALID   : in std_logic;
    S_AXI_AWREADY   : out std_logic;
    S_AXI_WDATA : in std_logic_vector(C_S_AXI_DATA_WIDTH-1 downto 0);
    S_AXI_WSTRB : in std_logic_vector((C_S_AXI_DATA_WIDTH/8)-1 downto 0);
    S_AXI_WVALID    : in std_logic;
    S_AXI_WREADY    : out std_logic;
    S_AXI_BRESP : out std_logic_vector(1 downto 0);
    S_AXI_BVALID    : out std_logic;
    S_AXI_BREADY    : in std_logic;
    S_AXI_ARADDR    : in std_logic_vector(C_S_AXI_ADDR_WIDTH-1 downto 0);
    S_AXI_ARPROT    : in std_logic_vector(2 downto 0);
    S_AXI_ARVALID   : in std_logic;
    S_AXI_ARREADY   : out std_logic;
    S_AXI_RDATA : out std_logic_vector(C_S_AXI_DATA_WIDTH-1 downto 0);
    S_AXI_RRESP : out std_logic_vector(1 downto 0);
    S_AXI_RVALID    : out std_logic;
    S_AXI_RREADY    : in std_logic
    );
end component my_ip_0_v1_0_S00_AXI;

begin

-- Instantiation of Axi Bus Interface S00_AXI
my_ip_0_v1_0_S00_AXI_inst : my_ip_0_v1_0_S00_AXI
generic map (
    C_S_AXI_DATA_WIDTH  => C_S00_AXI_DATA_WIDTH,
    C_S_AXI_ADDR_WIDTH  => C_S00_AXI_ADDR_WIDTH
)
port map (
    S_AXI_ACLK  => s00_axi_aclk,
    S_AXI_ARESETN   => s00_axi_aresetn,
    S_AXI_AWADDR    => s00_axi_awaddr,
    S_AXI_AWPROT    => s00_axi_awprot,
    S_AXI_AWVALID   => s00_axi_awvalid,
    S_AXI_AWREADY   => s00_axi_awready,
    S_AXI_WDATA => s00_axi_wdata,
    S_AXI_WSTRB => s00_axi_wstrb,
    S_AXI_WVALID    => s00_axi_wvalid,
    S_AXI_WREADY    => s00_axi_wready,
    S_AXI_BRESP => s00_axi_bresp,
    S_AXI_BVALID    => s00_axi_bvalid,
    S_AXI_BREADY    => s00_axi_bready,
    S_AXI_ARADDR    => s00_axi_araddr,
    S_AXI_ARPROT    => s00_axi_arprot,
    S_AXI_ARVALID   => s00_axi_arvalid,
    S_AXI_ARREADY   => s00_axi_arready,
    S_AXI_RDATA => s00_axi_rdata,
    S_AXI_RRESP => s00_axi_rresp,
    S_AXI_RVALID    => s00_axi_rvalid,
    S_AXI_RREADY    => s00_axi_rready
);

-- Add user logic here

-- User logic ends

end arch_imp;

1 个答案:

答案 0 :(得分:3)

my_ip_0_v1_0.vhd实例化my_ip_0_v1_0_S00_AXI.vhd,因此my_ip_0_v1_0.vhd是最高级别,您应该(如评论所述)将自定义代码放入my_ip_0_v1_0_S00_AXI.vhd。但事情有点复杂:在Zynq核心中,PS使用AXI总线协议与PL通信。因此,如果你想实现你的+1模块,最复杂的部分将是AXI协议(5个通道,握手......)并且自动生成的包装器过于复杂。您应该考虑查看AXI lite规范并实现最小的AXI lite兼容硬件。

无论如何,假设您想要将字符存储在地址0(b"00"),最低字节位置并且在写入时递增,您可以在内存映射寄存器选择中添加自定义代码,写逻辑生成进程:

when b"00" =>
  for byte_index in 0 to (C_S_AXI_DATA_WIDTH/8-1) loop
    if ( S_AXI_WSTRB(byte_index) = '1' ) then
      if byte_index = 0 then
        slv_reg0(7 downto 0) <= std_logic_vector(unsigned(S_AXI_WDATA(7 downto 0)) + 1);
      else
        slv_reg0(byte_index*8+7 downto byte_index*8) <= S_AXI_WDATA(byte_index*8+7 downto byte_index*8);
      end if;
    end if;
  end loop;

在外设地址空间的地址0处写入任何32位值,应保存未修改的24个最高有效位,并增加8个最低有效位(自动环绕0xff)。当然,要注意这一点,你必须回读地址0。