3 // USRP - Universal Software Radio Peripheral
5 // Copyright (C) 2003 Matt Ettus
7 // This program is free software; you can redistribute it and/or modify
8 // it under the terms of the GNU General Public License as published by
9 // the Free Software Foundation; either version 2 of the License, or
10 // (at your option) any later version.
12 // This program is distributed in the hope that it will be useful,
13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 // GNU General Public License for more details.
17 // You should have received a copy of the GNU General Public License
18 // along with this program; if not, write to the Free Software
19 // Foundation, Inc., 51 Franklin Street, Boston, MA 02110-1301 USA
22 module cordic(clock, reset, enable, xi, yi, zi, xo, yo, zo );
23 parameter bitwidth = 16;
24 parameter zwidth = 16;
29 input [bitwidth-1:0] xi, yi;
30 output [bitwidth-1:0] xo, yo;
31 input [zwidth-1:0] zi;
32 output [zwidth-1:0] zo;
34 reg [bitwidth+1:0] x0,y0;
36 wire [bitwidth+1:0] x1,x2,x3,x4,x5,x6,x7,x8,x9,x10,x11,x12;
37 wire [bitwidth+1:0] y1,y2,y3,y4,y5,y6,y7,y8,y9,y10,y11,y12;
38 wire [zwidth-2:0] z1,z2,z3,z4,z5,z6,z7,z8,z9,z10,z11,z12;
40 wire [bitwidth+1:0] xi_ext = {{2{xi[bitwidth-1]}},xi};
41 wire [bitwidth+1:0] yi_ext = {{2{yi[bitwidth-1]}},yi};
43 // Compute consts. Would be easier if vlog had atan...
44 // see gen_cordic_consts.py
64 always @(posedge clock)
67 x0 <= #1 0; y0 <= #1 0; z0 <= #1 0;
71 z0 <= #1 zi[zwidth-2:0];
72 case (zi[zwidth-1:zwidth-2])
83 endcase // case(zi[zwidth-1:zwidth-2])
84 end // else: !if(reset)
86 // FIXME need to handle variable number of stages
87 // FIXME should be able to narrow zwidth but quartus makes it bigger...
88 // This would be easier if arrays worked better in vlog...
89 cordic_stage #(bitwidth+2,zwidth-1,0) cordic_stage0 (clock,reset,enable,x0,y0,z0,`c00,x1,y1,z1);
90 cordic_stage #(bitwidth+2,zwidth-1,1) cordic_stage1 (clock,reset,enable,x1,y1,z1,`c01,x2,y2,z2);
91 cordic_stage #(bitwidth+2,zwidth-1,2) cordic_stage2 (clock,reset,enable,x2,y2,z2,`c02,x3,y3,z3);
92 cordic_stage #(bitwidth+2,zwidth-1,3) cordic_stage3 (clock,reset,enable,x3,y3,z3,`c03,x4,y4,z4);
93 cordic_stage #(bitwidth+2,zwidth-1,4) cordic_stage4 (clock,reset,enable,x4,y4,z4,`c04,x5,y5,z5);
94 cordic_stage #(bitwidth+2,zwidth-1,5) cordic_stage5 (clock,reset,enable,x5,y5,z5,`c05,x6,y6,z6);
95 cordic_stage #(bitwidth+2,zwidth-1,6) cordic_stage6 (clock,reset,enable,x6,y6,z6,`c06,x7,y7,z7);
96 cordic_stage #(bitwidth+2,zwidth-1,7) cordic_stage7 (clock,reset,enable,x7,y7,z7,`c07,x8,y8,z8);
97 cordic_stage #(bitwidth+2,zwidth-1,8) cordic_stage8 (clock,reset,enable,x8,y8,z8,`c08,x9,y9,z9);
98 cordic_stage #(bitwidth+2,zwidth-1,9) cordic_stage9 (clock,reset,enable,x9,y9,z9,`c09,x10,y10,z10);
99 cordic_stage #(bitwidth+2,zwidth-1,10) cordic_stage10 (clock,reset,enable,x10,y10,z10,`c10,x11,y11,z11);
100 cordic_stage #(bitwidth+2,zwidth-1,11) cordic_stage11 (clock,reset,enable,x11,y11,z11,`c11,x12,y12,z12);
102 assign xo = x12[bitwidth:1];
103 assign yo = y12[bitwidth:1];
104 //assign xo = x12[bitwidth+1:2]; // CORDIC gain is ~1.6, plus gain from rotating vectors
105 //assign yo = y12[bitwidth+1:2];