Initial Commit

1 files changed, 57 insertions, 0 deletions

diff --git a/Countdown.v b/Countdown.v
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+`timescale 1ns / 1ps
+//////////////////////////////////////////////////////////////////////////////////
+// Company: 
+// Engineer: 
+// 
+// Create Date:    14:51:02 03/16/2012 
+// Design Name: 
+// Module Name:    Countdown 
+// Project Name: 
+// Target Devices: 
+// Tool versions: 
+// Description: 
+//
+// Dependencies: 
+//
+// Revision: 
+// Revision 0.01 - File Created
+// Additional Comments: 
+//
+//////////////////////////////////////////////////////////////////////////////////
+module Countdown(
+    input clk_1hz,
+    input rst,
+    input start,
+    input [7:0] init,
+    output [7:0] t
+    );
+
+reg [7:0] t;
+reg running = 0;
+
+always @(init) begin
+	if (!running) begin
+		t = init;
+	end else begin
+		t = t;
+	end
+end
+
+always @(posedge clk_1hz) begin
+	if (running) begin
+		t <= t - 1;
+	end else begin
+		t <= init;
+	end
+end
+
+always @(posedge start) begin
+	running = 1;
+end
+
+always @(rst) begin
+	running = 0;
+	t = 0;
+end
+
+endmodule