用verilog写一个AXI4的Master接口

好的，以下是一个简单的AXI4 Master接口的Verilog代码示例：

module axi_master (
    input logic clk,
    input logic reset,
    input logic [31:0] write_data,
    output logic [31:0] read_data,
    input logic [31:0] address,
    input logic write_enable,
    input logic read_enable,
    output logic write_done,
    output logic read_done,
    output logic [1:0] response
);

// AXI4 write channel signals
logic [31:0] awaddr;
logic [7:0] awlen;
logic [2:0] awsize;
logic [1:0] awburst;
logic [1:0] awcache;
logic [3:0] awprot;
logic [3:0] awqos;
logic [1:0] awuser;
logic awvalid;
logic awready;
logic [31:0] wdata;
logic [3:0] wstrb;
logic wlast;
logic [1:0] wuser;
logic wvalid;
logic wready;
logic [1:0] buser;
logic bvalid;
logic bready;
logic [1:0] response_reg;

// AXI4 read channel signals
logic [31:0] araddr;
logic [7:0] arlen;
logic [2:0] arsize;
logic [1:0] arburst;
logic [1:0] arcache;
logic [3:0] arprot;
logic [3:0] arqos;
logic [1:0] aruser;
logic arvalid;
logic arready;
logic [31:0] rdata;
logic [1:0] ruser;
logic rvalid;
logic rready;

// Internal state machine
localparam IDLE = 2'b00;
localparam WRITE = 2'b01;
localparam READ = 2'b10;

logic [1:0] state;
logic write_complete;
logic read_complete;

always_ff @ (posedge clk) begin
    if (reset) begin
        state <= IDLE;
        awready <= 0;
        wready <= 0;
        bvalid <= 0;
        rvalid <= 0;
        response_reg <= 0;
        write_done <= 0;
        read_done <= 0;
    end
    else begin
        case (state)
            IDLE: begin
                if (write_enable) begin
                    state <= WRITE;
                    awaddr <= address;
                    awlen <= 0;
                    awsize <= 2'b10; // 32-bit transfers
                    awburst <= 2'b01; // Incrementing burst
                    awcache <= 2'b1111; // Non-cacheable
                    awprot <= 2'b0011; // Normal, Non-privileged access
                    awqos <= 0;
                    awuser <= 0;
                    awvalid <= 1;
                end
                else if (read_enable) begin
                    state <= READ;
                    araddr <= address;
                    arlen <= 0;
                    arsize <= 2'b10; // 32-bit transfers
                    arburst <= 2'b01; // Incrementing burst
                    arcache <= 2'b1111; // Non-cacheable
                    arprot <= 2'b0011; // Normal, Non-privileged access
                    arqos <= 0;
                    aruser <= 0;
                    arvalid <= 1;
                end
            end
            WRITE: begin
                if (awready && wready && !write_complete) begin
                    // Write address phase
                    awvalid <= 0;
                    wdata <= write_data;
                    wstrb <= {4{1'b1}}; // All bytes are valid
                    wlast <= 1;
                    wuser <= 0;
                    wvalid <= 1;
                    // Write data phase
                    awaddr <= awaddr + 4; // Increment address
                    awlen <= awlen + 1;
                    if (awlen == 0) begin
                        write_complete <= 1;
                    end
                end
                else if (bvalid) begin
                    response_reg <= response;
                    write_done <= 1;
                    state <= IDLE;
                end
            end
            READ: begin
                if (arready && !read_complete) begin
                    // Read address phase
                    arvalid <= 0;
                    // Read data phase
                    ruser <= 0;
                    rvalid <= 1;
                    if (rready) begin
                        read_data <= rdata;
                        read_complete <= 1;
                    end
                end
                else if (rvalid) begin
                    response_reg <= response;
                    read_done <= 1;
                    state <= IDLE;
                end
            end
        endcase
    end
end

// AXI4 write channel interface
assign awready = (state == WRITE) && !write_complete;
assign wready = (state == WRITE) && !write_complete;
assign buser = 0;
assign bready = 1;
assign response = response_reg;

// AXI4 read channel interface
assign arready = (state == READ) && !read_complete;
assign ruser = 0;
assign rready = 1;

endmodule

这个代码模块包含了一个简单的AXI4 Master接口，它支持单个32位地址和数据传输。它包括一个状态机，可以执行AXI4协议中的读和写事务，并在事务完成时发出完成信号。该模块可以作为一个IP核心，用于在FPGA中实现AXI4主设备接口。