moved usrp1 and usrp2 fpga dirs into fpga subdirectory

1 files changed, 157 insertions, 0 deletions

diff --git a/fpga/usrp2/sdr_lib/hb_interp.v b/fpga/usrp2/sdr_lib/hb_interp.v
new file mode 100644
index 000000000..d16807e15
--- /dev/null
+++ b/fpga/usrp2/sdr_lib/hb_interp.v
@@ -0,0 +1,157 @@
+// First halfband iterpolator 
+// Implements impulse responses of the form [A 0 B 0 C .. 0 H 0.5 H 0 .. C 0 B 0 A]
+// Strobe in cannot come faster than every 4th clock cycle, 
+// Strobe out cannot come faster than every 2nd clock cycle
+
+// These taps designed by halfgen4 from ldoolittle
+// myfilt = round(2^18 * halfgen4(.7/4,8))
+
+module hb_interp
+  #(parameter IWIDTH=18, OWIDTH=18, ACCWIDTH=24)
+    (input clk,
+     input rst,
+     input bypass,
+     input [7:0] cpo, //  Clocks per output, must be at least 2
+     input stb_in,
+     input [IWIDTH-1:0] data_in,
+     input stb_out,
+     output reg [OWIDTH-1:0] data_out);
+
+   localparam MWIDTH = ACCWIDTH-2;
+   localparam CWIDTH = 18;
+
+   reg [CWIDTH-1:0] coeff1, coeff2;
+   reg [3:0] 	    addr_a, addr_b, addr_c, addr_d, addr_e;
+   wire [IWIDTH-1:0] data_a, data_b, data_c, data_d, data_e, sum1, sum2;
+   wire [35:0] 	     prod1, prod2;
+
+   reg [2:0] 	     phase, phase_d1, phase_d2, phase_d3, phase_d4, phase_d5;
+
+   always @(posedge clk)
+     if(rst)
+       phase <= 0;
+     else
+       if(stb_in)
+	 phase <= 1;
+       else if(phase==4)
+	 phase <= 0;
+       else if(phase!=0)
+	 phase <= phase + 1;
+   always @(posedge clk) phase_d1 <= phase;
+   always @(posedge clk) phase_d2 <= phase_d1;
+   always @(posedge clk) phase_d3 <= phase_d2;
+   always @(posedge clk) phase_d4 <= phase_d3;
+   always @(posedge clk) phase_d5 <= phase_d4;     
+   
+   srl #(.WIDTH(IWIDTH)) srl_a
+     (.clk(clk),.write(stb_in),.in(data_in),.addr(addr_a),.out(data_a));
+   srl #(.WIDTH(IWIDTH)) srl_b
+     (.clk(clk),.write(stb_in),.in(data_in),.addr(addr_b),.out(data_b));
+   srl #(.WIDTH(IWIDTH)) srl_c
+     (.clk(clk),.write(stb_in),.in(data_in),.addr(addr_c),.out(data_c));
+   srl #(.WIDTH(IWIDTH)) srl_d
+     (.clk(clk),.write(stb_in),.in(data_in),.addr(addr_d),.out(data_d));
+   srl #(.WIDTH(IWIDTH)) srl_e
+     (.clk(clk),.write(stb_in),.in(data_in),.addr(addr_e),.out(data_e));
+
+   always @*
+     case(phase)
+       1 : begin addr_a = 0; addr_b = 15; end
+       2 : begin addr_a = 1; addr_b = 14; end
+       3 : begin addr_a = 2; addr_b = 13; end
+       4 : begin addr_a = 3; addr_b = 12; end
+       default : begin addr_a = 0; addr_b = 15; end
+     endcase // case(phase)
+
+   always @*
+     case(phase)
+       1 : begin addr_c = 4; addr_d = 11; end
+       2 : begin addr_c = 5; addr_d = 10; end
+       3 : begin addr_c = 6; addr_d = 9; end
+       4 : begin addr_c = 7; addr_d = 8; end
+       default : begin addr_c = 4; addr_d = 11; end
+     endcase // case(phase)
+
+   always @*
+     case(cpo)
+       2 : addr_e <= 9;
+       3,4,5,6,7,8 : addr_e <= 8;
+       default : addr_e <= 7;  // This case works for 256, which = 0 due to overflow outside this block
+     endcase // case(cpo)
+   
+   always @*            // Outer coeffs
+     case(phase_d1)
+       1 : coeff1 = -107;
+       2 : coeff1 = 445;
+       3 : coeff1 = -1271;
+       4 : coeff1 = 2959;
+       default : coeff1 = -107;
+     endcase // case(phase)
+   
+   always @*            //  Inner coeffs
+     case(phase_d1)
+       1 : coeff2 = -6107;
+       2 : coeff2 = 11953;
+       3 : coeff2 = -24706;
+       4 : coeff2 = 82359;
+       default : coeff2 = -6107;
+     endcase // case(phase)
+
+   add2_reg /*_and_round_reg*/ #(.WIDTH(IWIDTH)) add1 (.clk(clk),.in1(data_a),.in2(data_b),.sum(sum1));
+   add2_reg /*_and_round_reg*/ #(.WIDTH(IWIDTH)) add2 (.clk(clk),.in1(data_c),.in2(data_d),.sum(sum2));
+   // sum1, sum2 available on phase_d1
+
+   wire do_mult = 1;
+   MULT18X18S mult1(.C(clk), .CE(do_mult), .R(rst), .P(prod1), .A(coeff1), .B(sum1) );
+   MULT18X18S mult2(.C(clk), .CE(do_mult), .R(rst), .P(prod2), .A(coeff2), .B(sum2) );
+   // prod1, prod2 available on phase_d2
+   
+   wire [MWIDTH-1:0] sum_of_prod;
+   
+   add2_and_round_reg #(.WIDTH(MWIDTH)) 
+     add3 (.clk(clk),.in1(prod1[35:36-MWIDTH]),.in2(prod2[35:36-MWIDTH]),.sum(sum_of_prod));
+   // sum_of_prod available on phase_d3
+   
+   wire [ACCWIDTH-1:0] acc_out;
+   wire [OWIDTH-1:0]   acc_round;
+
+   wire 	       clear = (phase_d3 == 1);
+   wire 	       do_acc = (phase_d3 != 0);
+   
+   acc #(.IWIDTH(MWIDTH),.OWIDTH(ACCWIDTH)) 
+     acc (.clk(clk),.clear(clear),.acc(do_acc),.in(sum_of_prod),.out(acc_out));   
+   // acc_out available on phase_d4
+   
+   wire [ACCWIDTH-6:0] clipped_acc;
+   clip #(.bits_in(ACCWIDTH),.bits_out(ACCWIDTH-5)) final_clip(.in(acc_out),.out(clipped_acc));
+   
+   reg [ACCWIDTH-6:0]   clipped_reg;
+   always @(posedge clk)
+     if(phase_d4 == 4)
+       clipped_reg <= clipped_acc;
+   // clipped_reg available on phase_d5
+   
+   wire [OWIDTH-1:0]   data_out_round;
+   round #(.bits_in(ACCWIDTH-5),.bits_out(OWIDTH)) final_round (.in(clipped_reg),.out(data_out_round));
+
+   reg 		      odd;
+   always @(posedge clk)
+     if(rst)
+       odd <= 0;
+     else if(stb_in)
+       odd <= 0;
+     else if(stb_out)
+       odd <= 1;
+
+   always @(posedge clk)
+     if(bypass)
+       data_out <= data_in;
+     else if(stb_out)
+       if(odd)
+	 data_out <= data_e;
+       else
+	 data_out <= data_out_round;
+
+   // data_out available on phase_d6
+   
+endmodule // hb_interp