DreamSourceLab_DSLogic-hdl/src/reset.v

/*
 * This file is part of the DSLogic-hdl project.
 *
 * Copyright (C) 2014 DreamSourceLab <support@dreamsourcelab.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
 */

`timescale 1ns/100ps
`define D #1

module reset(
	// -- raw
	input	core_clk,
	input	sample_clk,
	input	sd_clk,
	input	usb_clk,
	input	sys_rst,
	input	sys_clr,

	// -- sync
	output	core_rst,
	output	sample_rst,
	output	sd_rst,
	output	sdram_rst_,
	output	cfg_rst,
	output	usb_rst
);

wire	clr_rst;
assign clr_rst = sys_rst | sys_clr;

// --
// core reset sync & stretch
// --
reg	[3:0]	core_rst_reg;
wire	[3:0]	core_rst_reg_nxt;

assign core_rst = core_rst_reg[3];
assign core_rst_reg_nxt = {core_rst_reg[2:0], 1'b0};
always @(posedge core_clk or posedge clr_rst)
begin
	if (clr_rst)
		core_rst_reg <= `D 4'b1111;
	else
		core_rst_reg <= `D core_rst_reg_nxt;
end

// --
// sample reset sync & stretch
// --
reg	[17:0]	sample_rst_reg;
wire	[17:0]	sample_rst_reg_nxt;

assign sample_rst = sample_rst_reg[17];
assign sample_rst_reg_nxt = {sample_rst_reg[16:0], 1'b0};
always @(posedge sample_clk or posedge clr_rst)
begin
	if (clr_rst)
		sample_rst_reg <= `D 18'b111111111111111111;
	else
		sample_rst_reg <= `D sample_rst_reg_nxt;
end

// --
// dwrite/dread reset sync & stretch
// --
reg	[3:0]	sd_rst_reg;
wire	[3:0]	sd_rst_reg_nxt;

assign sd_rst = sd_rst_reg[3];
assign sd_rst_reg_nxt = {sd_rst_reg[2:0], 1'b0};
always @(posedge sd_clk or posedge clr_rst)
begin
	if (clr_rst)
		sd_rst_reg <= `D 4'b1111;
	else
		sd_rst_reg <= `D sd_rst_reg_nxt;
end

// --
// sdram controller reset sync & stretch
// --
reg	[3:0]	sdram_rst_reg = 4'b0;
wire	[3:0]	sdram_rst_reg_nxt;

assign sdram_rst_ = sdram_rst_reg[3];
assign sdram_rst_reg_nxt = {sdram_rst_reg[2:0], 1'b1};
always @(posedge sd_clk)
begin
		sdram_rst_reg <= `D sdram_rst_reg_nxt;
end

// --
// cfg reset sync & stretch
// --
reg	[3:0]	cfg_rst_reg;
wire	[3:0]	cfg_rst_reg_nxt;

assign cfg_rst = cfg_rst_reg[3];
assign cfg_rst_reg_nxt = {cfg_rst_reg[2:0], 1'b0};
always @(posedge usb_clk or posedge sys_rst)
begin
	if (sys_rst)
		cfg_rst_reg <= `D 4'b1111;
	else
		cfg_rst_reg <= `D cfg_rst_reg_nxt;
end

// --
// usb controller reset sync & stretch
// --
reg	[3:0]	usb_rst_reg;
wire	[3:0]	usb_rst_reg_nxt;

assign usb_rst = usb_rst_reg[3];
assign usb_rst_reg_nxt = {usb_rst_reg[2:0], 1'b0};
always @(posedge usb_clk or posedge clr_rst)
begin
	if (clr_rst)
		usb_rst_reg <= `D 4'b1111;
	else
		usb_rst_reg <= `D usb_rst_reg_nxt;
end


endmodule