package GlitchFilter;

import Cntrs::*;

(* always_enabled="_write",always_ready="_read" *)
module mkGlitchFilter(Integer hysteresis, bit init_value, Reg#(bit) ifc);
   Wire#(bit) in <- mkBypassWire();
   UCount cnt <- mkUCount(init_value == 0 ? 0 : hysteresis, hysteresis);
   Reg#(bit) out[2] <- mkCReg(2, init_value);

   (* no_implicit_conditions, fire_when_enabled *)
   rule incr (cnt.isLessThan(fromInteger(hysteresis)) && in == 1);
      cnt.incr(1);
   endrule

   (* no_implicit_conditions, fire_when_enabled *)
   rule decr (cnt.isGreaterThan(0) && in == 0);
      cnt.decr(1);
   endrule

   (* no_implicit_conditions, fire_when_enabled *)
   rule set_out (cnt.isEqual(0) || cnt.isEqual(fromInteger(hysteresis)));
      out[0] <= cnt.isEqual(0) ? 0 : 1;
   endrule

   method _write = in._write;
   method _read = out[1]._read;
endmodule

endpackage