1 files changed, 80 insertions, 17 deletions
diff --git a/hdl/main_sp605.v b/hdl/main_sp605.v
index 1b4f9f2..a5e25b3 100644
--- a/hdl/main_sp605.v
+++ b/hdl/main_sp605.v
@@ -1,31 +1,94 @@
-// very minimal example top-level module
+/*
+ * main_sp605.v
+ *
+ * Copyright: (C) 2013 LeafLabs, LLC
+ * License: MIT License (See LICENSE file)
+ * Author: Bryan Newbold <bnewbold@leaflabs.com>
+ * Date: May-June 2013
+ *
+ * This top-level module contains only device-specific instantiations and
+ * wiring. It connects central_core (the top-level functional module) with
+ * specific device resources (DCMs, buffers, etc) and I/O Pads.
+ *
+ * This file is for use with the Xilinx SP605 development board, for
+ * development purposes before porting to the LeafLabs WiredLeaf board.
+ *
+ * It is assumed that a 25MHz crystal is inserted into the User Clock module
+ * on the SP605, replacing the default 27MHz crystal.
+ *
+ * TODO: test this in hardware
+ */
 
 module main (
-    output reg [3:0] gpio_led,
-    input wire [3:0] gpio_switch,
-    input wire SYSTEMCLOCK,
-    input wire PUSH_BUTTON_RESET_RAW // this is active low
-    );
+    // Clocks
+    input wire reset_button,
+    input wire user_clock,
+
+    // GPIO, LEDs, Buttons
+    input wire[3:0] gpio_switch,
+    input wire[3:0] gpio_button,
+    inout wire[3:0] gpio_header,
+    output wire[3:0] gpio_led,
+
+    // UART
+    input wire uart_rx,
+    output wire uart_tx
+
+    );  // don't forget to remove trailing comma!
 
     wire reset;
-    assign reset = !PUSH_BUTTON_RESET_RAW;
+    assign reset = reset_button;
+    wire clock_25mhz;
+    assign clock_25mhz = user_clock;
+
+    reg [23:0] throb_counter = 0;
+    reg throb_led = 0;
+    assign gpio_led[0] = throb_led;
 
-    reg [25:0] throb_counter = 0;
+    wire [7:0] rx_byte;
+    wire [7:0] tx_byte;
+    wire uart_flag;
+    assign gpio_led[1] = uart_flag;
+    simple_uart #(
+        .CLOCK_DIVIDE(651) // for (non-standard) 25MHz clock 
+    ) simple_uart_inst (
+        .clk(clock_25mhz),
+        .rst(reset),
+        .rx(uart_rx),
+        .tx(uart_tx),
+        .transmit(uart_flag),
+        .tx_byte(tx_byte),
+        .received(uart_flag),
+        .rx_byte(rx_byte),
+        .is_receiving(),
+        .is_transmitting(),
+        .recv_error()
+    );
+
+    rot13 rot13_inst (
+        .clock(clock_25mhz),
+        .reset(reset),
+        .in_char(rx_byte),
+        .out_char(tx_byte)
+    );
 
-    always @(posedge SYSTEMCLOCK) begin
+    always @(posedge clock_25mhz) begin
         if (reset) begin
-            gpio_led <= 7'b1111;
-            throb_counter <= 26'd0;
+            throb_counter <= 0;
+            throb_led <= 0;
         end else begin
-            gpio_led[1:0] <= gpio_switch[1:0];
-            gpio_led[2] <= gpio_switch[2] || gpio_switch[3];
-            if (throb_counter >= 26'd50_000_000) begin
-                gpio_led[3] <= !gpio_led[3]; 
-                throb_counter <= 26'd0;
+            if (throb_counter >= 24'd12_500_000) begin
+                throb_led <= !throb_led;
+                throb_counter <= 24'd0;
             end else begin
-                throb_counter <= throb_counter + 26'd1;
+                throb_counter <= throb_counter + 24'd1;
             end
         end
     end
 
+    // Tie off extra signals
+    assign gpio_led[3:2] = 0;
+    assign gpio_header = gpio_switch;
+
 endmodule
+