DE2 Quartus debounced circuit

In case it's useful, this is a general purpose filter I use for IO pins. Debouncing is a special case. The logic is very tight and fast. You'll need to adjust the freq, limit, and N to suit your needs.

module filter(input clock,
              input in,
              output reg out,  // out a filtered version of in
              output reg strobe); // true for one cycle synchronous with a change
   parameter freq = 25_000_000; // 25MHz
   parameter limit =    50_000; // 50kHz
   parameter dur = freq / limit;
   parameter N = 14; // INV: 2**N > dur;
   reg  countdown;
   // Filter out any meta stability
   reg       in_, in__;
   always @(posedge clock) begin
      strobe <= 0;
      in_ <= in;
      in__ <= in_;
      if (in__ == out)
        countdown <= dur - 1;
        // Note, we depend on countdown being reset here.
      else if (~countdown)
        countdown <= countdown - 1;
      else begin
         out <= ~out;
         strobe <= 1;
      end
   end
endmodule