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//
// Copyright 2011 Ettus Research LLC
//
// 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 3 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, see <http://www.gnu.org/licenses/>.
//
module packet_generator
(input clk, input reset, input clear,
output reg [7:0] data_o, output sof_o, output eof_o,
input [127:0] header,
output src_rdy_o, input dst_rdy_i);
localparam len = 32'd2000;
reg [31:0] state;
reg [31:0] seq;
reg [31:0] crc_out;
wire calc_crc = src_rdy_o & dst_rdy_i & ~(state[31:2] == 30'h3FFF_FFFF);
always @(posedge clk)
if(reset | clear)
seq <= 0;
else
if(eof_o & src_rdy_o & dst_rdy_i)
seq <= seq + 1;
always @(posedge clk)
if(reset | clear)
state <= 0;
else
if(src_rdy_o & dst_rdy_i)
if(state == (len - 1))
state <= 32'hFFFF_FFFC;
else
state <= state + 1;
always @*
case(state)
0 : data_o <= len[31:24];
1 : data_o <= len[23:16];
2 : data_o <= len[15:8];
3 : data_o <= len[7:0];
4 : data_o <= seq[31:24];
5 : data_o <= seq[23:16];
6 : data_o <= seq[15:8];
7 : data_o <= seq[7:0];
8 : data_o <= header[7:0];
9 : data_o <= header[15:8];
10 : data_o <= header[23:16];
11 : data_o <= header[31:24];
12 : data_o <= header[39:32];
13 : data_o <= header[47:40];
14 : data_o <= header[55:48];
15 : data_o <= header[63:56];
16 : data_o <= header[71:64];
17 : data_o <= header[79:72];
18 : data_o <= header[87:80];
19 : data_o <= header[95:88];
20 : data_o <= header[103:96];
21 : data_o <= header[111:104];
22 : data_o <= header[119:112];
23 : data_o <= header[127:120];
32'hFFFF_FFFC : data_o <= crc_out[31:24];
32'hFFFF_FFFD : data_o <= crc_out[23:16];
32'hFFFF_FFFE : data_o <= crc_out[15:8];
32'hFFFF_FFFF : data_o <= crc_out[7:0];
default : data_o <= state[7:0];
endcase // case (state)
assign src_rdy_o = 1;
assign sof_o = (state == 0);
assign eof_o = (state == 32'hFFFF_FFFF);
wire clear_crc = eof_o & src_rdy_o & dst_rdy_i;
// crc crc(.clk(clk), .reset(reset), .clear(clear_crc), .data(data_o),
// .calc(calc_crc), .crc_out(crc_out), .match());
always @(posedge clk)
if(reset | clear | clear_crc)
crc_out <= 0;
else
if(calc_crc)
crc_out <= crc_out + data_o;
endmodule // packet_generator
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