pluto_hdl_adi/library/util_axis_fifo/address_gray_pipelined.v

139 lines
3.9 KiB
Verilog

// ***************************************************************************
// ***************************************************************************
// Copyright 2014 - 2017 (c) Analog Devices, Inc. All rights reserved.
//
// This core 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.
//
// Redistribution and use of source or resulting binaries, with or without modification
// of this file, are permitted under one of the following two license terms:
//
// 1. The GNU General Public License version 2 as published by the
// Free Software Foundation, which can be found in the top level directory of
// the repository (LICENSE_GPL2), and at: <https://www.gnu.org/licenses/old-licenses/gpl-2.0.html>
//
// OR
//
// 2. An ADI specific BSD license as noted in the top level directory, or on-line at:
// https://github.com/analogdevicesinc/hdl/blob/master/LICENSE_ADIBSD
// This will allow to generate bit files and not release the source code,
// as long as it attaches to an ADI device.
//
// ***************************************************************************
// ***************************************************************************
module fifo_address_gray_pipelined (
input m_axis_aclk,
input m_axis_aresetn,
input m_axis_ready,
output reg m_axis_valid,
output [ADDRESS_WIDTH-1:0] m_axis_raddr,
output reg [ADDRESS_WIDTH:0] m_axis_level,
input s_axis_aclk,
input s_axis_aresetn,
output reg s_axis_ready,
input s_axis_valid,
output reg s_axis_empty,
output [ADDRESS_WIDTH-1:0] s_axis_waddr,
output reg [ADDRESS_WIDTH:0] s_axis_room
);
parameter ADDRESS_WIDTH = 4;
reg [ADDRESS_WIDTH:0] _s_axis_waddr = 'h00;
reg [ADDRESS_WIDTH:0] _s_axis_waddr_next;
wire [ADDRESS_WIDTH:0] _s_axis_raddr;
reg [ADDRESS_WIDTH:0] _m_axis_raddr = 'h00;
reg [ADDRESS_WIDTH:0] _m_axis_raddr_next;
wire [ADDRESS_WIDTH:0] _m_axis_waddr;
assign s_axis_waddr = _s_axis_waddr[ADDRESS_WIDTH-1:0];
assign m_axis_raddr = _m_axis_raddr[ADDRESS_WIDTH-1:0];
always @(*)
begin
if (s_axis_ready && s_axis_valid)
_s_axis_waddr_next <= _s_axis_waddr + 1;
else
_s_axis_waddr_next <= _s_axis_waddr;
end
always @(posedge s_axis_aclk)
begin
if (s_axis_aresetn == 1'b0) begin
_s_axis_waddr <= 'h00;
end else begin
_s_axis_waddr <= _s_axis_waddr_next;
end
end
always @(*)
begin
if (m_axis_ready && m_axis_valid)
_m_axis_raddr_next <= _m_axis_raddr + 1;
else
_m_axis_raddr_next <= _m_axis_raddr;
end
always @(posedge m_axis_aclk)
begin
if (m_axis_aresetn == 1'b0) begin
_m_axis_raddr <= 'h00;
end else begin
_m_axis_raddr <= _m_axis_raddr_next;
end
end
sync_gray #(
.DATA_WIDTH(ADDRESS_WIDTH + 1)
) i_waddr_sync (
.in_clk(s_axis_aclk),
.in_resetn(s_axis_aresetn),
.out_clk(m_axis_aclk),
.out_resetn(m_axis_aresetn),
.in_count(_s_axis_waddr),
.out_count(_m_axis_waddr)
);
sync_gray #(
.DATA_WIDTH(ADDRESS_WIDTH + 1)
) i_raddr_sync (
.in_clk(m_axis_aclk),
.in_resetn(m_axis_aresetn),
.out_clk(s_axis_aclk),
.out_resetn(s_axis_aresetn),
.in_count(_m_axis_raddr),
.out_count(_s_axis_raddr)
);
always @(posedge s_axis_aclk)
begin
if (s_axis_aresetn == 1'b0) begin
s_axis_ready <= 1'b1;
s_axis_empty <= 1'b1;
s_axis_room <= 2**ADDRESS_WIDTH;
end else begin
s_axis_ready <= (_s_axis_raddr[ADDRESS_WIDTH] == _s_axis_waddr_next[ADDRESS_WIDTH] ||
_s_axis_raddr[ADDRESS_WIDTH-1:0] != _s_axis_waddr_next[ADDRESS_WIDTH-1:0]);
s_axis_empty <= _s_axis_raddr == _s_axis_waddr_next;
s_axis_room <= _s_axis_raddr - _s_axis_waddr_next + 2**ADDRESS_WIDTH;
end
end
always @(posedge m_axis_aclk)
begin
if (m_axis_aresetn == 1'b0) begin
m_axis_valid <= 1'b0;
m_axis_level <= 'h00;
end else begin
m_axis_valid <= _m_axis_waddr != _m_axis_raddr_next;
m_axis_level <= _m_axis_waddr - _m_axis_raddr_next;
end
end
endmodule