24 bit wide z. Can't do this parameterized, unfortunately.

git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@10256 221aa14e-8319-0410-a670-987f0aec2ac5

diff --git a/usrp2/fpga/sdr_lib/cordic_z24.v b/usrp2/fpga/sdr_lib/cordic_z24.v
new file mode 100644 (file)
index 0000000..cf668d5
--- /dev/null
+++ b/usrp2/fpga/sdr_lib/cordic_z24.v
@@ -0,0 +1,126 @@
+// -*- verilog -*-
+//
+//  USRP - Universal Software Radio Peripheral
+//
+//  Copyright (C) 2003, 2007 Matt Ettus
+//
+//  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 2 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, write to the Free Software
+//  Foundation, Inc., 51 Franklin Street, Boston, MA  02110-1301  USA
+//
+
+module cordic_z24(clock, reset, enable, xi, yi, zi, xo, yo, zo );
+   parameter bitwidth = 16;
+   parameter stages = 19;
+   localparam zwidth = 24;
+   
+   input clock;
+   input reset;
+   input enable;
+   input [bitwidth-1:0] xi, yi;
+   output [bitwidth-1:0] xo, yo;
+   input [zwidth-1:0] zi;
+   output [zwidth-1:0] zo;
+   
+   reg [bitwidth+1:0]   x0,y0;
+   reg [zwidth-2:0]     z0;
+   wire [bitwidth+1:0]          x1,x2,x3,x4,x5,x6,x7,x8,x9,x10,x11,x12,x13,x14,x15,x16,x17,x18,x19,x20;
+   wire [bitwidth+1:0]          y1,y2,y3,y4,y5,y6,y7,y8,y9,y10,y11,y12,y13,y14,y15,y16,y17,y18,y19,y20;
+   wire [zwidth-2:0]    z1,z2,z3,z4,z5,z6,z7,z8,z9,z10,z11,z12,z13,z14,z15,z16,z17,z18,z19,z20;
+   
+   wire [bitwidth+1:0] xi_ext = {{2{xi[bitwidth-1]}},xi};
+   wire [bitwidth+1:0] yi_ext = {{2{yi[bitwidth-1]}},yi};
+
+   // Compute consts.  Would be easier if vlog had atan...
+   // see gen_cordic_consts.py
+
+   // constants for 24 bit wide phase
+   localparam         c00 = 24'd2097152;
+   localparam         c01 = 24'd1238021;
+   localparam         c02 = 24'd654136;
+   localparam         c03 = 24'd332050;
+   localparam         c04 = 24'd166669;
+   localparam         c05 = 24'd83416;
+   localparam         c06 = 24'd41718;
+   localparam         c07 = 24'd20860;
+   localparam         c08 = 24'd10430;
+   localparam         c09 = 24'd5215;
+   localparam         c10 = 24'd2608;
+   localparam         c11 = 24'd1304;
+   localparam         c12 = 24'd652;
+   localparam         c13 = 24'd326;
+   localparam         c14 = 24'd163;
+   localparam         c15 = 24'd81;
+   localparam         c16 = 24'd41;
+   localparam         c17 = 24'd20;
+   localparam         c18 = 24'd10;
+   localparam         c19 = 24'd5;
+   localparam         c20 = 24'd3;
+   localparam         c21 = 24'd1;
+   localparam         c22 = 24'd1;
+   localparam         c23 = 24'd0;
+
+   always @(posedge clock)
+     if(reset)
+       begin
+         x0   <= 0; y0   <= 0;  z0   <= 0;
+       end
+     else// if(enable)
+       begin
+         z0 <= zi[zwidth-2:0];
+         case (zi[zwidth-1:zwidth-2])
+           2'b00, 2'b11 : 
+             begin
+                x0 <= xi_ext;
+                y0 <= yi_ext;
+             end
+           2'b01, 2'b10 :
+             begin
+                x0 <= -xi_ext;
+                y0 <= -yi_ext;
+             end
+         endcase // case(zi[zwidth-1:zwidth-2])
+       end // else: !if(reset)
+   
+   // FIXME need to handle variable number of stages
+   // This would be easier if arrays worked better in vlog...
+   
+   cordic_stage #(bitwidth+2,zwidth-1,0) cordic_stage0 (clock,reset,enable,x0,y0,z0,c00,x1,y1,z1);
+   cordic_stage #(bitwidth+2,zwidth-1,1) cordic_stage1 (clock,reset,enable,x1,y1,z1,c01,x2,y2,z2);
+   cordic_stage #(bitwidth+2,zwidth-1,2) cordic_stage2 (clock,reset,enable,x2,y2,z2,c02,x3,y3,z3);
+   cordic_stage #(bitwidth+2,zwidth-1,3) cordic_stage3 (clock,reset,enable,x3,y3,z3,c03,x4,y4,z4);
+   cordic_stage #(bitwidth+2,zwidth-1,4) cordic_stage4 (clock,reset,enable,x4,y4,z4,c04,x5,y5,z5);
+   cordic_stage #(bitwidth+2,zwidth-1,5) cordic_stage5 (clock,reset,enable,x5,y5,z5,c05,x6,y6,z6);
+   cordic_stage #(bitwidth+2,zwidth-1,6) cordic_stage6 (clock,reset,enable,x6,y6,z6,c06,x7,y7,z7);
+   cordic_stage #(bitwidth+2,zwidth-1,7) cordic_stage7 (clock,reset,enable,x7,y7,z7,c07,x8,y8,z8);
+   cordic_stage #(bitwidth+2,zwidth-1,8) cordic_stage8 (clock,reset,enable,x8,y8,z8,c08,x9,y9,z9);
+   cordic_stage #(bitwidth+2,zwidth-1,9) cordic_stage9 (clock,reset,enable,x9,y9,z9,c09,x10,y10,z10);
+   cordic_stage #(bitwidth+2,zwidth-1,10) cordic_stage10 (clock,reset,enable,x10,y10,z10,c10,x11,y11,z11);
+   cordic_stage #(bitwidth+2,zwidth-1,11) cordic_stage11 (clock,reset,enable,x11,y11,z11,c11,x12,y12,z12);
+   cordic_stage #(bitwidth+2,zwidth-1,12) cordic_stage12 (clock,reset,enable,x12,y12,z12,c12,x13,y13,z13);
+   cordic_stage #(bitwidth+2,zwidth-1,13) cordic_stage13 (clock,reset,enable,x13,y13,z13,c13,x14,y14,z14);
+   cordic_stage #(bitwidth+2,zwidth-1,14) cordic_stage14 (clock,reset,enable,x14,y14,z14,c14,x15,y15,z15);
+   cordic_stage #(bitwidth+2,zwidth-1,15) cordic_stage15 (clock,reset,enable,x15,y15,z15,c15,x16,y16,z16);
+   cordic_stage #(bitwidth+2,zwidth-1,16) cordic_stage16 (clock,reset,enable,x16,y16,z16,c16,x17,y17,z17);
+   cordic_stage #(bitwidth+2,zwidth-1,17) cordic_stage17 (clock,reset,enable,x17,y17,z17,c17,x18,y18,z18);
+   cordic_stage #(bitwidth+2,zwidth-1,18) cordic_stage18 (clock,reset,enable,x18,y18,z18,c18,x19,y19,z19);
+   cordic_stage #(bitwidth+2,zwidth-1,19) cordic_stage19 (clock,reset,enable,x19,y19,z19,c19,x20,y20,z20);
+
+   assign xo = x20[bitwidth:1];  
+   assign yo = y20[bitwidth:1];
+   assign zo = z20;              
+   //assign xo = x20[bitwidth+1:2];  // CORDIC gain is ~1.6, plus gain from rotating vectors
+   //assign yo = y20[bitwidth+1:2];
+
+endmodule // cordic
+

diff --git a/usrp2/fpga/sdr_lib/dsp_core_rx.v b/usrp2/fpga/sdr_lib/dsp_core_rx.v
index 64c82bbda0cb0838f3b5be03874d3e3511348b09..716182f65c9162a63e14427d849b92aca200c0e0 100644 (file)
--- a/usrp2/fpga/sdr_lib/dsp_core_rx.v
+++ b/usrp2/fpga/sdr_lib/dsp_core_rx.v
@@ -107,9 +107,10 @@ module dsp_core_rx
       .R(rst)     // Synchronous reset input
       ); 
 
-   cordic #(.bitwidth(24))
+   
+   cordic_z24 #(.bitwidth(24))
      cordic(.clock(clk), .reset(rst), .enable(run),
-           .xi(prod_i[23:0]),. yi(prod_q[23:0]), .zi(phase[31:16]),
+           .xi(prod_i[23:0]),. yi(prod_q[23:0]), .zi(phase[31:8]),
            .xo(i_cordic),.yo(q_cordic),.zo() );
 
    cic_strober cic_strober(.clock(clk),.reset(rst),.enable(run),.rate(cic_decim_rate),

diff --git a/usrp2/fpga/sdr_lib/gen_cordic_consts.py b/usrp2/fpga/sdr_lib/gen_cordic_consts.py
index ab66cfe01a757fe5c72f8d95a54d425eec8c54cd..261e8c223c2076928dd50682de28e750a033fb72 100755 (executable)
--- a/usrp2/fpga/sdr_lib/gen_cordic_consts.py
+++ b/usrp2/fpga/sdr_lib/gen_cordic_consts.py
@@ -2,9 +2,9 @@
 
 import math
 
-zwidth = 16
+zwidth = 24
 
-for i in range(17):
+for i in range(24):
     c = math.atan (1.0/(2**i)) / (2 * math.pi) * (1 << zwidth)
-    print "`define c%02d %d'd%d" % (i, zwidth, round (c))
+    print "localparam c%02d = %d'd%d;" % (i, zwidth, round (c))