dsp rework: u2_core test implementation

1 files changed, 145 insertions, 0 deletions

diff --git a/usrp2/sdr_lib/ddc_chain.v b/usrp2/sdr_lib/ddc_chain.v
new file mode 100644
index 000000000..7f51d2865
--- /dev/null
+++ b/usrp2/sdr_lib/ddc_chain.v
@@ -0,0 +1,145 @@
+//
+// 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/>.
+//
+
+//! The USRP digital down-conversion chain
+
+module ddc_chain
+  #(parameter BASE = 160)
+  (input clk, input rst,
+   input set_stb, input [7:0] set_addr, input [31:0] set_data,
+
+   input [23:0] adc_i,
+   input [23:0] adc_q,
+   
+   output [31:0] sample,
+   input run,
+   output strobe,
+   output [31:0] debug
+   );
+
+   wire [31:0] phase_inc;
+   reg [31:0]  phase;
+
+   wire [24:0] i_cordic, q_cordic;
+   wire [23:0] i_cordic_clip, q_cordic_clip;
+   wire [23:0] i_cic, q_cic;
+   wire [23:0] i_hb1, q_hb1;
+   wire [23:0] i_hb2, q_hb2;
+   
+   wire        strobe_cic, strobe_hb1, strobe_hb2;
+   wire        enable_hb1, enable_hb2;
+   wire [7:0]  cic_decim_rate;
+
+   reg [23:0]  adc_i_mux, adc_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)) sr_1
+     (.clk(clk),.rst(rst),.strobe(set_stb),.addr(set_addr),
+      .in(set_data),.out({scale_i,scale_q}),.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
+	  adc_i_mux <= adc_q;
+	  adc_q_mux <= realmode ? 24'd0 : adc_i;
+       end
+     else
+       begin
+	  adc_i_mux <= adc_i;
+	  adc_q_mux <= realmode ? 24'd0 : adc_q;
+       end
+
+   // NCO
+   always @(posedge clk)
+     if(rst)
+       phase <= 0;
+     else if(~run)
+       phase <= 0;
+     else
+       phase <= phase + phase_inc;
+
+   // CORDIC  24-bit I/O
+   cordic_z24 #(.bitwidth(25))
+     cordic(.clock(clk), .reset(rst), .enable(run),
+	    .xi({adc_i_mux[23],adc_i_mux}),. yi({adc_q_mux[23],adc_q_mux}), .zi(phase[31:8]),
+	    .xo(i_cordic),.yo(q_cordic),.zo() );
+
+   clip_reg #(.bits_in(25), .bits_out(24)) clip_i
+     (.clk(clk), .in(i_cordic), .strobe_in(1'b1), .out(i_cordic_clip));
+   clip_reg #(.bits_in(25), .bits_out(24)) 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(run),.rate(cic_decim_rate),
+			   .strobe_fast(1),.strobe_slow(strobe_cic) );
+
+   cic_decim #(.bw(24))
+     decim_i (.clock(clk),.reset(rst),.enable(run),
+	      .rate(cic_decim_rate),.strobe_in(1'b1),.strobe_out(strobe_cic),
+	      .signal_in(i_cordic_clip),.signal_out(i_cic));
+   
+   cic_decim #(.bw(24))
+     decim_q (.clock(clk),.reset(rst),.enable(run),
+	      .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(24)) small_hb_i
+     (.clk(clk),.rst(rst),.bypass(~enable_hb1),.run(run),
+      .stb_in(strobe_cic),.data_in(i_cic),.stb_out(strobe_hb1),.data_out(i_hb1));
+   
+   small_hb_dec #(.WIDTH(24)) small_hb_q
+     (.clk(clk),.rst(rst),.bypass(~enable_hb1),.run(run),
+      .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(24)) hb_i
+     (.clk(clk),.rst(rst),.bypass(~enable_hb2),.run(run),.cpi(cpi_hb),
+      .stb_in(strobe_hb1),.data_in(i_hb1),.stb_out(strobe_hb2),.data_out(i_hb2));
+
+   hb_dec #(.WIDTH(24)) hb_q
+     (.clk(clk),.rst(rst),.bypass(~enable_hb2),.run(run),.cpi(cpi_hb),
+      .stb_in(strobe_hb1),.data_in(q_hb1),.stb_out(),.data_out(q_hb2));
+
+   // Round final answer to 16 bits
+   round_sd #(.WIDTH_IN(24),.WIDTH_OUT(16)) round_i
+     (.clk(clk),.reset(rst), .in(i_hb2),.strobe_in(strobe_hb2), .out(sample[31:16]), .strobe_out(strobe));
+
+   round_sd #(.WIDTH_IN(24),.WIDTH_OUT(16)) round_q
+     (.clk(clk),.reset(rst), .in(q_hb2),.strobe_in(strobe_hb2), .out(sample[15:0]), .strobe_out());
+   
+   assign      debug = {enable_hb1, enable_hb2, run, strobe, strobe_cic, strobe_hb1, strobe_hb2};
+   
+endmodule // ddc_chain