aboutsummaryrefslogtreecommitdiffstats
path: root/fpga/usrp2/sdr_lib/ddc_chain.v
diff options
context:
space:
mode:
Diffstat (limited to 'fpga/usrp2/sdr_lib/ddc_chain.v')
-rw-r--r--fpga/usrp2/sdr_lib/ddc_chain.v190
1 files changed, 0 insertions, 190 deletions
diff --git a/fpga/usrp2/sdr_lib/ddc_chain.v b/fpga/usrp2/sdr_lib/ddc_chain.v
deleted file mode 100644
index c32c9f491..000000000
--- a/fpga/usrp2/sdr_lib/ddc_chain.v
+++ /dev/null
@@ -1,190 +0,0 @@
-//
-// Copyright 2011-2012 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/>.
-//
-
-//! The USRP digital down-conversion chain
-
-module ddc_chain
- #(
- parameter BASE = 0,
- parameter DSPNO = 0,
- parameter WIDTH = 24
- )
- (input clk, input rst, input clr,
- input set_stb, input [7:0] set_addr, input [31:0] set_data,
- input set_stb_user, input [7:0] set_addr_user, input [31:0] set_data_user,
-
- // From RX frontend
- input [WIDTH-1:0] rx_fe_i,
- input [WIDTH-1:0] rx_fe_q,
-
- // To RX control
- output [31:0] sample,
- input run,
- output strobe,
- output [31:0] debug
- );
-
- localparam cwidth = 25;
- localparam zwidth = 24;
-
- wire ddc_enb;
- wire [31:0] phase_inc;
- reg [31:0] phase;
-
- wire [17:0] scale_factor;
- wire [cwidth-1:0] i_cordic, q_cordic;
- wire [WIDTH-1:0] i_cordic_clip, q_cordic_clip;
- wire [WIDTH-1:0] i_cic, q_cic;
- wire [WIDTH-1:0] i_hb1, q_hb1;
- wire [WIDTH-1:0] i_hb2, q_hb2;
-
- wire strobe_cic, strobe_hb1, strobe_hb2;
- wire enable_hb1, enable_hb2;
- wire [7:0] cic_decim_rate;
-
- reg [WIDTH-1:0] rx_fe_i_mux, rx_fe_q_mux;
- wire realmode;
- wire swap_iq;
-
- setting_reg #(.my_addr(BASE+0)) sr_0
- (.clk(clk),.rst(rst),.strobe(set_stb),.addr(set_addr),
- .in(set_data),.out(phase_inc),.changed());
-
- setting_reg #(.my_addr(BASE+1), .width(18)) sr_1
- (.clk(clk),.rst(rst),.strobe(set_stb),.addr(set_addr),
- .in(set_data),.out(scale_factor),.changed());
-
- setting_reg #(.my_addr(BASE+2), .width(10)) sr_2
- (.clk(clk),.rst(rst),.strobe(set_stb),.addr(set_addr),
- .in(set_data),.out({enable_hb1, enable_hb2, cic_decim_rate}),.changed());
-
- setting_reg #(.my_addr(BASE+3), .width(2)) sr_3
- (.clk(clk),.rst(rst),.strobe(set_stb),.addr(set_addr),
- .in(set_data),.out({realmode,swap_iq}),.changed());
-
- // MUX so we can do realmode signals on either input
-
- always @(posedge clk)
- if(swap_iq)
- begin
- rx_fe_i_mux <= rx_fe_q;
- rx_fe_q_mux <= realmode ? 0 : rx_fe_i;
- end
- else
- begin
- rx_fe_i_mux <= rx_fe_i;
- rx_fe_q_mux <= realmode ? 0 : rx_fe_q;
- end
-
- // NCO
- always @(posedge clk)
- if(rst)
- phase <= 0;
- else if(~ddc_enb)
- phase <= 0;
- else
- phase <= phase + phase_inc;
-
- //sign extension of cordic input
- wire [WIDTH-1:0] to_ddc_chain_i, to_ddc_chain_q;
- wire [cwidth-1:0] to_cordic_i, to_cordic_q;
- sign_extend #(.bits_in(WIDTH), .bits_out(cwidth)) sign_extend_cordic_i (.in(to_ddc_chain_i), .out(to_cordic_i));
- sign_extend #(.bits_in(WIDTH), .bits_out(cwidth)) sign_extend_cordic_q (.in(to_ddc_chain_q), .out(to_cordic_q));
-
- // CORDIC 24-bit I/O
- cordic_z24 #(.bitwidth(cwidth))
- cordic(.clock(clk), .reset(rst), .enable(ddc_enb),
- .xi(to_cordic_i),. yi(to_cordic_q), .zi(phase[31:32-zwidth]),
- .xo(i_cordic),.yo(q_cordic),.zo() );
-
- clip_reg #(.bits_in(cwidth), .bits_out(WIDTH)) clip_i
- (.clk(clk), .in(i_cordic), .strobe_in(1'b1), .out(i_cordic_clip));
- clip_reg #(.bits_in(cwidth), .bits_out(WIDTH)) clip_q
- (.clk(clk), .in(q_cordic), .strobe_in(1'b1), .out(q_cordic_clip));
-
- // CIC decimator 24 bit I/O
- cic_strober cic_strober(.clock(clk),.reset(rst),.enable(ddc_enb),.rate(cic_decim_rate),
- .strobe_fast(1),.strobe_slow(strobe_cic) );
-
- cic_decim #(.bw(WIDTH))
- decim_i (.clock(clk),.reset(rst),.enable(ddc_enb),
- .rate(cic_decim_rate),.strobe_in(1'b1),.strobe_out(strobe_cic),
- .signal_in(i_cordic_clip),.signal_out(i_cic));
-
- cic_decim #(.bw(WIDTH))
- decim_q (.clock(clk),.reset(rst),.enable(ddc_enb),
- .rate(cic_decim_rate),.strobe_in(1'b1),.strobe_out(strobe_cic),
- .signal_in(q_cordic_clip),.signal_out(q_cic));
-
- // First (small) halfband 24 bit I/O
- small_hb_dec #(.WIDTH(WIDTH)) small_hb_i
- (.clk(clk),.rst(rst),.bypass(~enable_hb1),.run(ddc_enb),
- .stb_in(strobe_cic),.data_in(i_cic),.stb_out(strobe_hb1),.data_out(i_hb1));
-
- small_hb_dec #(.WIDTH(WIDTH)) small_hb_q
- (.clk(clk),.rst(rst),.bypass(~enable_hb1),.run(ddc_enb),
- .stb_in(strobe_cic),.data_in(q_cic),.stb_out(),.data_out(q_hb1));
-
- // Second (large) halfband 24 bit I/O
- wire [8:0] cpi_hb = enable_hb1 ? {cic_decim_rate,1'b0} : {1'b0,cic_decim_rate};
- hb_dec #(.WIDTH(WIDTH)) hb_i
- (.clk(clk),.rst(rst),.bypass(~enable_hb2),.run(ddc_enb),.cpi(cpi_hb),
- .stb_in(strobe_hb1),.data_in(i_hb1),.stb_out(strobe_hb2),.data_out(i_hb2));
-
- hb_dec #(.WIDTH(WIDTH)) hb_q
- (.clk(clk),.rst(rst),.bypass(~enable_hb2),.run(ddc_enb),.cpi(cpi_hb),
- .stb_in(strobe_hb1),.data_in(q_hb1),.stb_out(),.data_out(q_hb2));
-
- //scalar operation (gain of 6 bits)
- wire [35:0] prod_i, prod_q;
-
- MULT18X18S mult_i
- (.P(prod_i), .A(i_hb2[WIDTH-1:WIDTH-18]), .B(scale_factor), .C(clk), .CE(strobe_hb2), .R(rst) );
- MULT18X18S mult_q
- (.P(prod_q), .A(q_hb2[WIDTH-1:WIDTH-18]), .B(scale_factor), .C(clk), .CE(strobe_hb2), .R(rst) );
-
- //pipeline for the multiplier (gain of 10 bits)
- reg [WIDTH-1:0] prod_reg_i, prod_reg_q;
- reg strobe_mult;
-
- always @(posedge clk) begin
- strobe_mult <= strobe_hb2;
- prod_reg_i <= prod_i[33:34-WIDTH];
- prod_reg_q <= prod_q[33:34-WIDTH];
- end
-
- // Round final answer to 16 bits
- wire [31:0] ddc_chain_out;
- wire ddc_chain_stb;
-
- round_sd #(.WIDTH_IN(WIDTH),.WIDTH_OUT(16)) round_i
- (.clk(clk),.reset(rst), .in(prod_reg_i),.strobe_in(strobe_mult), .out(ddc_chain_out[31:16]), .strobe_out(ddc_chain_stb));
-
- round_sd #(.WIDTH_IN(WIDTH),.WIDTH_OUT(16)) round_q
- (.clk(clk),.reset(rst), .in(prod_reg_q),.strobe_in(strobe_mult), .out(ddc_chain_out[15:0]), .strobe_out());
-
- dsp_rx_glue #(.DSPNO(DSPNO), .WIDTH(WIDTH)) custom(
- .clock(clk), .reset(rst), .clear(clr), .enable(run),
- .set_stb(set_stb_user), .set_addr(set_addr_user), .set_data(set_data_user),
- .frontend_i(rx_fe_i_mux), .frontend_q(rx_fe_q_mux),
- .ddc_in_i(to_ddc_chain_i), .ddc_in_q(to_ddc_chain_q),
- .ddc_out_sample(ddc_chain_out), .ddc_out_strobe(ddc_chain_stb), .ddc_out_enable(ddc_enb),
- .bb_sample(sample), .bb_strobe(strobe));
-
- assign debug = {enable_hb1, enable_hb2, run, strobe, strobe_cic, strobe_hb1, strobe_hb2};
-
-endmodule // ddc_chain
generated by cgit v1.2.3 (git 2.39.1) at 2025-08-05 18:05:37 +0000