1 files changed, 75 insertions, 0 deletions
diff --git a/src/rtl/eim.v b/src/rtl/eim.v
new file mode 100644
index 0000000..dcbd226
--- /dev/null
+++ b/src/rtl/eim.v
@@ -0,0 +1,75 @@
+`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,
+
+   // 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.
+   );
+
+   // XXX add NAME0/NAME1/VERSION
+
+   //----------------------------------------------------------------
+   // 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(sys_rst),
+      .eim_active(sys_eim_wr | sys_eim_rd),
+      .led_out(led_pin)
+      );
+
+
+endmodule // eim