`define USE_EIM

module eim
  (
   // EIM interface pins from CPU
   input wire 	       eim_bclk, // EIM burst clock. Started by the CPU.
   input wire 	       eim_cs0_n, // Chip select (active low).
   inout wire [15 : 0] eim_da, // Bidirectional address and data port.
   input wire [18: 16] eim_a, // MSB part of address port.                     
   input wire 	       eim_lba_n, // Latch address signal (active low).
   input wire 	       eim_wr_n, // write enable signal (active low).
   input wire 	       eim_oe_n, // output enable signal (active low).
   output wire 	       eim_wait_n, // Data wait signal (active low).

   // system clock and reset
   input wire 	       sys_clk,
   input wire 	       sys_rst_n,

   // EIM interface to cores
   output wire [16: 0] sys_eim_addr,
   output wire 	       sys_eim_wr,
   output wire 	       sys_eim_rd,
   output wire [31: 0] sys_eim_dout,
   input wire [31: 0]  sys_eim_din,

   // Novena utility ports
   output wire 	       led_pin		// LED on edge close to the FPGA.
   );

   //----------------------------------------------------------------
   // EIM Arbiter
   //
   // EIM arbiter handles EIM access and transfers it into
   // `sys_clk' clock domain.
   //----------------------------------------------------------------

   eim_arbiter eim
     (
      .eim_bclk(eim_bclk),
      .eim_cs0_n(eim_cs0_n),
      .eim_da(eim_da),
      .eim_a(eim_a),
      .eim_lba_n(eim_lba_n),
      .eim_wr_n(eim_wr_n),
      .eim_oe_n(eim_oe_n),
      .eim_wait_n(eim_wait_n),

      .sys_clk(sys_clk),

      .sys_addr(sys_eim_addr),
      .sys_wren(sys_eim_wr),
      .sys_data_out(sys_eim_dout),
      .sys_rden(sys_eim_rd),
      .sys_data_in(sys_eim_din)
      );


   //----------------------------------------------------------------
   // LED Driver
   //
   // A simple utility LED driver that turns on the Novena
   // board LED when the EIM interface is active.
   //----------------------------------------------------------------
   eim_indicator led
     (
      .sys_clk(sys_clk),
      .sys_rst_n(sys_rst_n),
      .eim_active(sys_eim_wr | sys_eim_rd),
      .led_out(led_pin)
      );


endmodule // eim