// pulse_stretch.sv
module pulse_stretch #(
  parameter int N = 4
) (
  input  logic clk, rst, in_pulse,
  output logic out
);
  localparam int CW = $clog2(N + 1);
  logic [CW-1:0] cnt;
  always_ff @(posedge clk)
    if (rst)              cnt <= '0;
    else if (in_pulse)    cnt <= CW'(N);       // (re)start the window
    else if (cnt != '0)   cnt <= cnt - 1'b1;
  assign out = (cnt != '0);
endmodule