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Diffstat (limited to 'fpga/usrp3/lib/rfnoc/periodic_framer.v')
| -rw-r--r-- | fpga/usrp3/lib/rfnoc/periodic_framer.v | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/fpga/usrp3/lib/rfnoc/periodic_framer.v b/fpga/usrp3/lib/rfnoc/periodic_framer.v new file mode 100644 index 000000000..3e83bcf8d --- /dev/null +++ b/fpga/usrp3/lib/rfnoc/periodic_framer.v @@ -0,0 +1,151 @@ +// +// Copyright 2014 Ettus Research LLC +// Copyright 2018 Ettus Research, a National Instruments Company +// +// SPDX-License-Identifier: LGPL-3.0-or-later +// + +module periodic_framer #( + parameter SR_FRAME_LEN = 0, + parameter SR_GAP_LEN = 1, + parameter SR_OFFSET = 2, + parameter SR_NUMBER_SYMBOLS_MAX = 3, + parameter SR_NUMBER_SYMBOLS_SHORT = 4, + // Skip a set number of gaps at the beginning. Use 1 to properly frame 802.11 long preamble. + parameter SKIP_GAPS = 1, + parameter WIDTH = 32) +( + input clk, input reset, input clear, + input set_stb, input [7:0] set_addr, input [31:0] set_data, + input [WIDTH-1:0] stream_i_tdata, input stream_i_tlast, input stream_i_tvalid, output stream_i_tready, + output [WIDTH-1:0] stream_o_tdata, output stream_o_tlast, output stream_o_tvalid, input stream_o_tready, + output reg sof, output reg eof); + + wire [15:0] frame_len; + wire [15:0] gap_len; + wire [15:0] offset; + + wire [15:0] numsymbols_max, numsymbols_thisburst, numsymbols_short; + wire [15:0] burst_len; + wire set_numsymbols; + wire consume; + reg [15:0] counter; + reg [$clog2(SKIP_GAPS):0] skip_cnt; + reg [15:0] numsymbols; + + setting_reg #(.my_addr(SR_FRAME_LEN), .width(16)) reg_frame_len ( + .clk(clk), .rst(reset), .strobe(set_stb), .addr(set_addr), .in(set_data), + .out(frame_len), .changed()); + + setting_reg #(.my_addr(SR_GAP_LEN), .width(16)) reg_gap_len ( + .clk(clk), .rst(reset), .strobe(set_stb), .addr(set_addr), .in(set_data), + .out(gap_len), .changed()); + + setting_reg #(.my_addr(SR_OFFSET), .width(16)) reg_offset ( + .clk(clk), .rst(reset), .strobe(set_stb), .addr(set_addr), .in(set_data), + .out(offset), .changed()); + + setting_reg #(.my_addr(SR_NUMBER_SYMBOLS_MAX), .width(16)) reg_max_symbols ( + .clk(clk), .rst(reset), .strobe(set_stb), .addr(set_addr), .in(set_data), + .out(numsymbols_max), .changed()); + + setting_reg #(.my_addr(SR_NUMBER_SYMBOLS_SHORT), .width(16)) reg_symbols_short ( + .clk(clk), .rst(reset), .strobe(set_stb), .addr(set_addr), .in(set_data), + .out(numsymbols_short), .changed(set_numsymbols)); + + reg [1:0] state; + localparam ST_WAIT_FOR_TRIG = 2'd0; + localparam ST_DO_OFFSET = 2'd1; + localparam ST_FRAME = 2'd2; + localparam ST_GAP = 2'd3; + + reg shorten_burst; + always @(posedge clk) begin + if (reset | clear) begin + shorten_burst <= 1'b0; + end else if (set_numsymbols) begin + shorten_burst <= 1'b1; + end else if(state == ST_WAIT_FOR_TRIG) begin + shorten_burst <= 1'b0; + end + end + + assign numsymbols_thisburst = shorten_burst ? numsymbols_short : numsymbols_max; + + always @(posedge clk) begin + if (reset | clear) begin + eof <= 1'b0; + sof <= 1'b0; + counter <= 1; + skip_cnt <= 0; + numsymbols <= 16'd1; + state <= ST_WAIT_FOR_TRIG; + end else begin + if (consume) begin + case(state) + ST_WAIT_FOR_TRIG : begin + eof <= 1'b0; + skip_cnt <= 0; + if (stream_i_tlast) begin + counter <= 16'b1; + if (offset == 0) begin + state <= ST_FRAME; + end else begin + state <= ST_DO_OFFSET; + end + end + end + + ST_DO_OFFSET : begin + if (counter >= offset) begin + sof <= 1'b1; + counter <= 16'b1; + numsymbols <= 16'd1; + state <= ST_FRAME; + end else begin + counter <= counter + 16'd1; + end + end + + ST_FRAME : begin + if (counter >= frame_len) begin + sof <= 1'b0; + counter <= 1; + numsymbols <= numsymbols + 1; + if (numsymbols >= numsymbols_thisburst) begin + eof <= 1'b1; + state <= ST_WAIT_FOR_TRIG; + end else begin + if (skip_cnt < SKIP_GAPS) begin + skip_cnt <= skip_cnt + 1; + state <= ST_FRAME; + end else begin + state <= ST_GAP; + end + end + end else begin + counter <= counter + 16'd1; + end + end + + ST_GAP : begin + if (counter >= gap_len) begin + state <= ST_FRAME; + counter <= 1; + end else begin + counter <= counter + 16'd1; + end + end + endcase + end + end + end + + assign stream_o_tdata = stream_i_tdata; + assign stream_o_tlast = (state == ST_FRAME) & (counter >= frame_len); + assign stream_o_tvalid = stream_i_tvalid & (state == ST_FRAME); + + assign stream_i_tready = consume; + assign consume = stream_i_tvalid & ((state != ST_FRAME) | stream_o_tready); + +endmodule // periodic_framer |