///////////////////////////////////////////////////////////////////////////////
//
// Pushbutton Debounce Module 
//
///////////////////////////////////////////////////////////////////////////////

module debounce (reset, clk, noisy, clean);
   input reset, clk, noisy;
   output clean;

   parameter NDELAY = 650000;
   parameter NBITS = 20;

   reg [NBITS-1:0] count;
   reg xnew, clean;

   always @(posedge clk)
     if (reset) begin xnew <= noisy; clean <= noisy; count <= 0; end
     else if (noisy != xnew) begin xnew <= noisy; count <= 0; end
     else if (count == NDELAY) clean <= xnew;
     else count <= count+1;

endmodule