diff options
Diffstat (limited to 'fpga/usrp2/fifo/fifo36_to_fifo19.v')
-rw-r--r-- | fpga/usrp2/fifo/fifo36_to_fifo19.v | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/fpga/usrp2/fifo/fifo36_to_fifo19.v b/fpga/usrp2/fifo/fifo36_to_fifo19.v new file mode 100644 index 000000000..cb93e10ad --- /dev/null +++ b/fpga/usrp2/fifo/fifo36_to_fifo19.v @@ -0,0 +1,80 @@ +// +// 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/>. +// + + +// Parameter LE tells us if we are little-endian. +// Little-endian means send lower 16 bits first. +// Default is big endian (network order), send upper bits first. + +module fifo36_to_fifo19 + #(parameter LE=0) + (input clk, input reset, input clear, + input [35:0] f36_datain, + input f36_src_rdy_i, + output f36_dst_rdy_o, + + output [18:0] f19_dataout, + output f19_src_rdy_o, + input f19_dst_rdy_i ); + + wire [18:0] f19_data_int; + wire f19_src_rdy_int, f19_dst_rdy_int; + wire [35:0] f36_data_int; + wire f36_src_rdy_int, f36_dst_rdy_int; + + // Shortfifo on input to guarantee no deadlock + fifo_short #(.WIDTH(36)) head_fifo + (.clk(clk),.reset(reset),.clear(clear), + .datain(f36_datain), .src_rdy_i(f36_src_rdy_i), .dst_rdy_o(f36_dst_rdy_o), + .dataout(f36_data_int), .src_rdy_o(f36_src_rdy_int), .dst_rdy_i(f36_dst_rdy_int), + .space(),.occupied() ); + + // Main fifo36_to_fifo19, needs shortfifos to guarantee no deadlock + wire [1:0] f36_occ_int = f36_data_int[35:34]; + wire f36_sof_int = f36_data_int[32]; + wire f36_eof_int = f36_data_int[33]; + + reg phase; + wire half_line = f36_eof_int & ((f36_occ_int==1)|(f36_occ_int==2)); + + assign f19_data_int[15:0] = (LE ^ phase) ? f36_data_int[15:0] : f36_data_int[31:16]; + assign f19_data_int[16] = phase ? 0 : f36_sof_int; + assign f19_data_int[17] = phase ? f36_eof_int : half_line; + assign f19_data_int[18] = f19_data_int[17] & ((f36_occ_int==1)|(f36_occ_int==3)); + + assign f19_src_rdy_int = f36_src_rdy_int; + assign f36_dst_rdy_int = (phase | half_line) & f19_dst_rdy_int; + + wire f19_xfer = f19_src_rdy_int & f19_dst_rdy_int; + wire f36_xfer = f36_src_rdy_int & f36_dst_rdy_int; + + always @(posedge clk) + if(reset) + phase <= 0; + else if(f36_xfer) + phase <= 0; + else if(f19_xfer) + phase <= 1; + + // Shortfifo on output to guarantee no deadlock + fifo_short #(.WIDTH(19)) tail_fifo + (.clk(clk),.reset(reset),.clear(clear), + .datain(f19_data_int), .src_rdy_i(f19_src_rdy_int), .dst_rdy_o(f19_dst_rdy_int), + .dataout(f19_dataout), .src_rdy_o(f19_src_rdy_o), .dst_rdy_i(f19_dst_rdy_i), + .space(),.occupied() ); + +endmodule // fifo36_to_fifo19 |