那avalon总线主设备更复杂的代码什么样子呢

Avalon总线主设备的代码通常比较复杂，因为主设备需要实现许多功能，如初始化Avalon总线、处理来自从设备的读写请求、生成中断等。

以下是一个简单的Avalon总线主设备代码示例：

module avalon_master (
  input clk,
  input reset_n,
  output reg [31:0] data_out,
  input [31:0] data_in,
  output reg write,
  output reg read,
  output reg [31:0] address,
  input [31:0] read_data,
  input ack
);

  // Avalon总线状态机定义
  typedef enum {
    IDLE = 0,
    READ_REQ,
    READ_WAIT,
    WRITE_REQ,
    WRITE_WAIT
  } state_t;

  reg [1:0] state;
  reg [31:0] counter;

  // 初始化状态机和计数器
  always @ (posedge clk) begin
    if (!reset_n) begin
      state <= IDLE;
      counter <= 0;
    end else begin
      case (state)
        IDLE: begin
          write <= 0;
          read <= 0;
          state <= READ_REQ;
        end
        READ_REQ: begin
          write <= 0;
          read <= 1;
          address <= counter;
          state <= READ_WAIT;
        end
        READ_WAIT: begin
          if (ack) begin
            data_out <= read_data;
            counter <= counter + 1;
            if (counter == 255) begin
              state <= WRITE_REQ;
            end else begin
              state <= READ_REQ;
            end
          end
        end
        WRITE_REQ: begin
          write <= 1;
          read <= 0;
          address <= counter;
          data_out <= data_in;
          state <= WRITE_WAIT;
        end
        WRITE_WAIT: begin
          if (ack) begin
            counter <= counter + 1;
            if (counter == 255) begin
              state <= IDLE;
            end else begin
              state <= READ_REQ;
            end
          end
        end
      endcase
    end
  end
endmodule

这个模块实现了一个简单的Avalon总线主设备，它在每个时钟周期上，根据当前状态执行不同的操作。在这个示例中，主设备从从设备读取数据并将其保存在data_out寄存器中，在写操作中，它通过data_in输入寄存器将数据写入从设备。计数器用于跟踪要访问的地址，并在达到最大值时返回IDLE状态。