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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/>.
//
// Mux packets from multiple FIFO interfaces onto a single one.
// Can alternate or give priority to one port (port 0)
// In prio mode, port 1 will never get access if port 0 is always busy
module fifo36_mux
#(parameter prio = 0)
(input clk, input reset, input clear,
input [35:0] data0_i, input src0_rdy_i, output dst0_rdy_o,
input [35:0] data1_i, input src1_rdy_i, output dst1_rdy_o,
output [35:0] data_o, output src_rdy_o, input dst_rdy_i);
wire [35:0] data0_int, data1_int;
wire src0_rdy_int, dst0_rdy_int, src1_rdy_int, dst1_rdy_int;
fifo_short #(.WIDTH(36)) mux_fifo_in0
(.clk(clk), .reset(reset), .clear(clear),
.datain(data0_i), .src_rdy_i(src0_rdy_i), .dst_rdy_o(dst0_rdy_o),
.dataout(data0_int), .src_rdy_o(src0_rdy_int), .dst_rdy_i(dst0_rdy_int));
fifo_short #(.WIDTH(36)) mux_fifo_in1
(.clk(clk), .reset(reset), .clear(clear),
.datain(data1_i), .src_rdy_i(src1_rdy_i), .dst_rdy_o(dst1_rdy_o),
.dataout(data1_int), .src_rdy_o(src1_rdy_int), .dst_rdy_i(dst1_rdy_int));
localparam MUX_IDLE0 = 0;
localparam MUX_DATA0 = 1;
localparam MUX_IDLE1 = 2;
localparam MUX_DATA1 = 3;
reg [1:0] state;
wire eof0 = data0_int[33];
wire eof1 = data1_int[33];
wire [35:0] data_int;
wire src_rdy_int, dst_rdy_int;
always @(posedge clk)
if(reset | clear)
state <= MUX_IDLE0;
else
case(state)
MUX_IDLE0 :
if(src0_rdy_int)
state <= MUX_DATA0;
else if(src1_rdy_int)
state <= MUX_DATA1;
MUX_DATA0 :
if(src0_rdy_int & dst_rdy_int & eof0)
state <= prio ? MUX_IDLE0 : MUX_IDLE1;
MUX_IDLE1 :
if(src1_rdy_int)
state <= MUX_DATA1;
else if(src0_rdy_int)
state <= MUX_DATA0;
MUX_DATA1 :
if(src1_rdy_int & dst_rdy_int & eof1)
state <= MUX_IDLE0;
default :
state <= MUX_IDLE0;
endcase // case (state)
assign dst0_rdy_int = (state==MUX_DATA0) ? dst_rdy_int : 0;
assign dst1_rdy_int = (state==MUX_DATA1) ? dst_rdy_int : 0;
assign src_rdy_int = (state==MUX_DATA0) ? src0_rdy_int : (state==MUX_DATA1) ? src1_rdy_int : 0;
assign data_int = (state==MUX_DATA0) ? data0_int : data1_int;
fifo_short #(.WIDTH(36)) mux_fifo
(.clk(clk), .reset(reset), .clear(clear),
.datain(data_int), .src_rdy_i(src_rdy_int), .dst_rdy_o(dst_rdy_int),
.dataout(data_o), .src_rdy_o(src_rdy_o), .dst_rdy_i(dst_rdy_i));
endmodule // fifo36_demux
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