InterruptConverter

module InterruptConverter (/*AUTOARG*/
   // Outputs
   edge_irq, irq_counter,
   // Inputs
   clk, rst_n, level_irq
   ) ;
   input clk;
   input rst_n;

   input            level_irq;
   output reg       edge_irq;
   output reg [7:0] irq_counter = 0;

   reg        [3:0] shift_register = 0;

   always @ ( posedge clk or negedge rst_n ) begin
      if (!rst_n) begin
        shift_register <= 0;
      end  else begin
          shift_register <= { shift_register[2:0], level_irq };

          if (shift_register[3] == 1 &&
              shift_register[2:0] != 3'b111) begin
             edge_irq <= 1;
          end else begin
             edge_irq <= 0;
          end
      end
   end

   always @ ( negedge level_irq or negedge rst_n ) begin
      if (!rst_n) begin
        irq_counter <= 0;
      end else begin
        irq_counter <= irq_counter + 1;
      end
   end

endmodule // InterruptConverter