Hazard3/hdl/debug/cdc/hazard3_reset_sync.v

/*****************************************************************************\
|                      Copyright (C) 2021-2022 Luke Wren                      |
|                     SPDX-License-Identifier: Apache-2.0                     |
\*****************************************************************************/

// The output is asserted asynchronously when the input is asserted,
// but deasserted synchronously when clocked with the input deasserted.
// Input and output are both active-low.
//
// This is a baseline implementation -- you should replace it with cells
// specific to your FPGA/process

`ifndef HAZARD3_REG_KEEP_ATTRIBUTE
`define HAZARD3_REG_KEEP_ATTRIBUTE (* keep = 1'b1 *)
`endif

`default_nettype none

module hazard3_reset_sync #(
	parameter N_STAGES = 2 // Should be >= 2
) (
	input  wire clk,
	input  wire rst_n_in,
	output wire rst_n_out
);

`HAZARD3_REG_KEEP_ATTRIBUTE reg [N_STAGES-1:0] delay;

always @ (posedge clk or negedge rst_n_in)
	if (!rst_n_in)
		delay <= {N_STAGES{1'b0}};
	else
		delay <= {delay[N_STAGES-2:0], 1'b1};

assign rst_n_out = delay[N_STAGES-1];

endmodule

`default_nettype wire