Squashed B200 FPGA Source. Code from Josh Blum, Ian Buckley, and Matt Ettus.

1 files changed, 146 insertions, 0 deletions

diff --git a/fpga/usrp3/lib/dsp/duc_chain.v b/fpga/usrp3/lib/dsp/duc_chain.v
new file mode 100644
index 000000000..06c87bd34
--- /dev/null
+++ b/fpga/usrp3/lib/dsp/duc_chain.v
@@ -0,0 +1,146 @@
+//
+// Copyright 2011-2013 Ettus Research LLC
+//
+
+
+//! The USRP digital up-conversion chain
+
+module duc_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,
+
+   // To TX frontend
+   output [WIDTH-1:0] tx_fe_i,
+   output [WIDTH-1:0] tx_fe_q,
+
+   // From TX control
+   input [31:0] sample,
+   input run,
+   output strobe,
+   output [31:0] debug
+   );
+
+   wire [17:0] scale_factor;
+   wire [31:0] phase_inc;
+   reg [31:0]  phase;
+   wire [7:0]  interp_rate;
+   wire [3:0]  tx_femux_a, tx_femux_b;
+   wire        enable_hb1, enable_hb2;
+   wire        rate_change;
+   
+   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, interp_rate}),.changed(rate_change));
+
+   // Strobes are all now delayed by 1 cycle for timing reasons
+   wire        strobe_cic_pre, strobe_hb1_pre, strobe_hb2_pre;
+   reg 	       strobe_cic = 1;
+   reg 	       strobe_hb1 = 1;
+   reg 	       strobe_hb2 = 1;
+
+  assign strobe = strobe_hb1;
+   
+   cic_strober #(.WIDTH(8))
+     cic_strober(.clock(clk),.reset(rst),.enable(run & ~rate_change),.rate(interp_rate),
+		 .strobe_fast(1),.strobe_slow(strobe_cic_pre) );
+   cic_strober #(.WIDTH(2))
+     hb2_strober(.clock(clk),.reset(rst),.enable(run & ~rate_change),.rate(enable_hb2 ? 2 : 1),
+		 .strobe_fast(strobe_cic_pre),.strobe_slow(strobe_hb2_pre) );
+   cic_strober #(.WIDTH(2))
+     hb1_strober(.clock(clk),.reset(rst),.enable(run & ~rate_change),.rate(enable_hb1 ? 2 : 1),
+		 .strobe_fast(strobe_hb2_pre),.strobe_slow(strobe_hb1_pre) );
+   
+   always @(posedge clk) strobe_hb1 <= strobe_hb1_pre;
+   always @(posedge clk) strobe_hb2 <= strobe_hb2_pre;
+   always @(posedge clk) strobe_cic <= strobe_cic_pre;
+
+   // NCO
+   always @(posedge clk)
+     if(rst)
+       phase <= 0;
+     else if(~run)
+       phase <= 0;
+     else
+       phase <= phase + phase_inc;
+   
+   wire        signed [17:0] da, db;
+   wire        signed [35:0] prod_i, prod_q;
+
+   assign tx_fe_i = prod_i[33:34-WIDTH];
+   assign tx_fe_q = prod_q[33:34-WIDTH];
+
+   wire [17:0] i_interp, q_interp;
+
+   wire [17:0] hb1_i, hb1_q, hb2_i, hb2_q;
+
+   wire [7:0]  cpo = enable_hb2 ? ({interp_rate,1'b0}) : interp_rate;
+   // Note that max CIC rate is 128, which would give an overflow on cpo if enable_hb2 is true,
+   //   but the default case inside hb_interp handles this
+   
+   hb_interp #(.IWIDTH(18),.OWIDTH(18),.ACCWIDTH(WIDTH)) hb_interp_i
+     (.clk(clk),.rst(rst),.bypass(~enable_hb1),.cpo(cpo),.stb_in(strobe_hb1),.data_in({sample[31:16], 2'b0}),.stb_out(strobe_hb2),.data_out(hb1_i));
+   hb_interp #(.IWIDTH(18),.OWIDTH(18),.ACCWIDTH(WIDTH)) hb_interp_q
+     (.clk(clk),.rst(rst),.bypass(~enable_hb1),.cpo(cpo),.stb_in(strobe_hb1),.data_in({sample[15:0], 2'b0}),.stb_out(strobe_hb2),.data_out(hb1_q));
+   
+   small_hb_int #(.WIDTH(18)) small_hb_interp_i
+     (.clk(clk),.rst(rst),.bypass(~enable_hb2),.stb_in(strobe_hb2),.data_in(hb1_i),
+      .output_rate(interp_rate),.stb_out(strobe_cic),.data_out(hb2_i));
+   small_hb_int #(.WIDTH(18)) small_hb_interp_q
+     (.clk(clk),.rst(rst),.bypass(~enable_hb2),.stb_in(strobe_hb2),.data_in(hb1_q),
+      .output_rate(interp_rate),.stb_out(strobe_cic),.data_out(hb2_q));
+   
+   cic_interp  #(.bw(18),.N(4),.log2_of_max_rate(7))
+     cic_interp_i(.clock(clk),.reset(rst),.enable(run & ~rate_change),.rate(interp_rate),
+		  .strobe_in(strobe_cic),.strobe_out(1),
+		  .signal_in(hb2_i),.signal_out(i_interp));
+   
+   cic_interp  #(.bw(18),.N(4),.log2_of_max_rate(7))
+     cic_interp_q(.clock(clk),.reset(rst),.enable(run & ~rate_change),.rate(interp_rate),
+		  .strobe_in(strobe_cic),.strobe_out(1),
+		  .signal_in(hb2_q),.signal_out(q_interp));
+
+   localparam  cwidth = WIDTH;  // was 18
+   localparam  zwidth = 24;  // was 16
+
+   wire [cwidth-1:0] da_c, db_c;
+   
+   cordic_z24 #(.bitwidth(cwidth))
+     cordic(.clock(clk), .reset(rst), .enable(run),
+	    .xi({i_interp,{(cwidth-18){1'b0}}}),.yi({q_interp,{(cwidth-18){1'b0}}}),
+	    .zi(phase[31:32-zwidth]),
+	    .xo(da_c),.yo(db_c),.zo() );
+   
+   MULT18X18S MULT18X18S_inst 
+     (.P(prod_i),    // 36-bit multiplier output
+      .A(da_c[cwidth-1:cwidth-18]),    // 18-bit multiplier input
+      .B(scale_factor),    // 18-bit multiplier input
+      .C(clk),    // Clock input
+      .CE(1),  // Clock enable input
+      .R(rst)     // Synchronous reset input
+      );
+   
+   MULT18X18S MULT18X18S_inst_2 
+     (.P(prod_q),    // 36-bit multiplier output
+      .A(db_c[cwidth-1:cwidth-18]),    // 18-bit multiplier input
+      .B(scale_factor),    // 18-bit multiplier input
+      .C(clk),    // Clock input
+      .CE(1),  // Clock enable input
+      .R(rst)     // Synchronous reset input
+      );
+
+   assign      debug = {strobe_cic, strobe_hb1, strobe_hb2,run};
+
+endmodule // duc_chain