用rtl写一个AXI4的Master接口

以下是一个简单的 AXI4 Master 接口的RTL实现：

module axi4_master (
    input clk,
    input rst,
    input [31:0] awaddr,
    input [7:0] awlen,
    input [2:0] awsize,
    input [1:0] awburst,
    input [3:0] awcache,
    input [2:0] awprot,
    input awvalid,
    output awready,
    input [31:0] wdata,
    input [3:0] wstrb,
    input wlast,
    input wvalid,
    output wready,
    output [31:0] bresp,
    output bvalid,
    input bready,
    input [31:0] araddr,
    input [7:0] arlen,
    input [2:0] arsize,
    input [1:0] arburst,
    input [3:0] arcache,
    input [2:0] arprot,
    input arvalid,
    output arready,
    output [31:0] rdata,
    output [1:0] rresp,
    output rlast,
    output rvalid,
    input rready
);

// 内部信号
reg [31:0] awaddr_reg;
reg [7:0] awlen_reg;
reg [2:0] awsize_reg;
reg [1:0] awburst_reg;
reg [3:0] awcache_reg;
reg [2:0] awprot_reg;
reg awvalid_reg;
wire awready_int;
assign awready = awready_int && !rst;
reg [31:0] wdata_reg;
reg [3:0] wstrb_reg;
reg wlast_reg;
reg wvalid_reg;
wire wready_int;
assign wready = wready_int && !rst;
wire [1:0] bresp_int;
assign bresp = bresp_int;
reg bvalid_reg;
wire bready_int;
assign bready_int = bready && !rst;
reg [31:0] araddr_reg;
reg [7:0] arlen_reg;
reg [2:0] arsize_reg;
reg [1:0] arburst_reg;
reg [3:0] arcache_reg;
reg [2:0] arprot_reg;
reg arvalid_reg;
wire arready_int;
assign arready = arready_int && !rst;
wire [1:0] rresp_int;
assign rresp = rresp_int;
wire rlast_int;
assign rlast = rlast_int;
wire rvalid_int;
assign rvalid = rvalid_int && !rst;
reg [31:0] rdata_reg;
wire rdata_int;
assign rdata = rdata_int;

// AW信号处理
always @(posedge clk) begin
    if (rst) begin
        awaddr_reg <= 0;
        awlen_reg <= 0;
        awsize_reg <= 0;
        awburst_reg <= 0;
        awcache_reg <= 0;
        awprot_reg <= 0;
        awvalid_reg <= 0;
    end else begin
        if (awvalid && awready_int) begin
            awaddr_reg <= awaddr;
            awlen_reg <= awlen;
            awsize_reg <= awsize;
            awburst_reg <= awburst;
            awcache_reg <= awcache;
            awprot_reg <= awprot;
            awvalid_reg <= 0;
        end else if (!awvalid) begin
            awvalid_reg <= 1;
        end
    end
end

// AWREADY信号处理
assign awready_int = 1'b1;

// W信号处理
always @(posedge clk) begin
    if (rst) begin
        wdata_reg <= 0;
        wstrb_reg <= 0;
        wlast_reg <= 0;
        wvalid_reg <= 0;
    end else begin
        if (wvalid && wready_int) begin
            wdata_reg <= wdata;
            wstrb_reg <= wstrb;
            wlast_reg <= wlast;
            wvalid_reg <= 0;
        end else if (!wvalid) begin
            wvalid_reg <= 1;
        end
    end
end

// WREADY信号处理
assign wready_int = 1'b1;

// B信号处理
always @(posedge clk) begin
    if (rst) begin
        bvalid_reg <= 0;
    end else begin
        if (bready_int && !bvalid_reg && awvalid && awready_int && wvalid && wready_int) begin
            bvalid_reg <= 1;
            bresp_int <= 0;
        end else if (bvalid_reg && bready_int) begin
            bvalid_reg <= 0;
        end
    end
end

// AR信号处理
always @(posedge clk) begin
    if (rst) begin
        araddr_reg <= 0;
        arlen_reg <= 0;
        arsize_reg <= 0;
        arburst_reg <= 0;
        arcache_reg <= 0;
        arprot_reg <= 0;
        arvalid_reg <= 0;
    end else begin
        if (arvalid && arready_int) begin
            araddr_reg <= araddr;
            arlen_reg <= arlen;
            arsize_reg <= arsize;
            arburst_reg <= arburst;
            arcache_reg <= arcache;
            arprot_reg <= arprot;
            arvalid_reg <= 0;
        end else if (!arvalid) begin
            arvalid_reg <= 1;
        end
    end
end

// ARREADY信号处理
assign arready_int = 1'b1;

// R信号处理
always @(posedge clk) begin
    if (rst) begin
        rdata_reg <= 0;
        rvalid_int <= 0;
        rlast_int <= 0;
    end else begin
        if (rready_int && !rvalid_int && arvalid && arready_int) begin
            rdata_reg <= rdata_int;
            rvalid_int <= 1;
            rlast_int <= 0;
            rresp_int <= 0;
        end else if (rvalid_int && rready_int) begin
            rvalid_int <= 0;
            rlast_int <= 1;
            rresp_int <= 0;
        end
    end
end

endmodule

这个接口实现了 AXI4 协议的所有必要信号。你可以将这个代码段作为一个开始，来根据你自己的需求进行修改和扩展。