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// synthesis translate_off
`timescale 1ns / 100ps
// synthesis translate_on
module SD_DAT (
                // inputs:
                 address,
                 chipselect,
                 clk,
                 reset_n,
                 write_n,
                 writedata,

                // outputs:
                 bidir_port,
                 readdata
              );

  inout            bidir_port;
  output           readdata;
  input   [  1: 0] address;
  input            chipselect;
  input            clk;
  input            reset_n;
  input            write_n;
  input            writedata;

  wire             bidir_port;
  wire             clk_en;
  reg              data_dir;
  wire             data_in;
  reg              data_out;
  wire             read_mux_out;
  reg              readdata;
  assign clk_en = 1;
  //s1, which is an e_avalon_slave
  assign read_mux_out = ({1 {(address == 0)}} & data_in) |
    ({1 {(address == 1)}} & data_dir);

  always @(posedge clk or negedge reset_n)
    begin
      if (reset_n == 0)
          readdata <= 0;
      else if (clk_en)
          readdata <= read_mux_out;
    end


  always @(posedge clk or negedge reset_n)
    begin
      if (reset_n == 0)
          data_out <= 0;
      else if (chipselect && ~write_n && (address == 0))
          data_out <= writedata;
    end


  assign bidir_port = data_dir ? data_out : 1'bZ;
  assign data_in = bidir_port;
  always @(posedge clk or negedge reset_n)
    begin
      if (reset_n == 0)
          data_dir <= 0;
      else if (chipselect && ~write_n && (address == 1))
          data_dir <= writedata;
    end




endmodule