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path: root/fpga/usrp2/sdr_lib/rx_frontend.v
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module rx_frontend
  #(parameter BASE = 0)
   (input clk, input rst,
    input set_stb, input [7:0] set_addr, input [31:0] set_data,

    input [15:0] adc_a, input adc_ovf_a,
    input [15:0] adc_b, input adc_ovf_b,

    output [23:0] i_out, output [23:0] q_out,
    input run,
    output [31:0] debug
    );
   
   reg [15:0] 	  adc_i, adc_q;
   wire [17:0] 	  adc_i_ofs, adc_q_ofs;
   wire [35:0] 	  corr_i, corr_q; wire [17:0] 	  mag_corr,phase_corr;
   wire 	  swap_iq;
   wire [23:0] 	  i_final, q_final;
   
   setting_reg #(.my_addr(BASE), .width(1)) sr_8
     (.clk(clk),.rst(rst),.strobe(set_stb),.addr(set_addr),
      .in(set_data),.out(swap_iq),.changed());

   always @(posedge clk)
     if(swap_iq) // Swap
       {adc_i,adc_q} <= {adc_b,adc_a};
     else
       {adc_i,adc_q} <= {adc_a,adc_b};
       
   setting_reg #(.my_addr(BASE+1),.width(18)) sr_1
     (.clk(clk),.rst(rst),.strobe(set_stb),.addr(set_addr),
      .in(set_data),.out(mag_corr),.changed());
   
   setting_reg #(.my_addr(BASE+2),.width(18)) sr_2
     (.clk(clk),.rst(rst),.strobe(set_stb),.addr(set_addr),
      .in(set_data),.out(phase_corr),.changed());
   
   rx_dcoffset #(.WIDTH(18),.ADDR(BASE+3)) rx_dcoffset_i
     (.clk(clk),.rst(rst),.set_stb(set_stb),.set_addr(set_addr),.set_data(set_data),
      .in({adc_i,2'b00}),.out(adc_i_ofs));
   
   rx_dcoffset #(.WIDTH(18),.ADDR(BASE+4)) rx_dcoffset_q
     (.clk(clk),.rst(rst),.set_stb(set_stb),.set_addr(set_addr),.set_data(set_data),
      .in({adc_q,2'b00}),.out(adc_q_ofs));
   
   MULT18X18S mult_mag_corr
     (.P(corr_i), .A(adc_i_ofs), .B(mag_corr), .C(clk), .CE(1), .R(rst) ); 

   MULT18X18S mult_phase_corr
     (.P(corr_q), .A(adc_i_ofs), .B(phase_corr), .C(clk), .CE(1), .R(rst) );
   
   add2_and_clip_reg #(.WIDTH(24)) add_clip_i
     (.clk(clk), .rst(rst), 
      .in1({adc_i_ofs,6'd0}), .in2({{4{corr_i[35]}},corr_i[35:16]}), .strobe_in(1'b1), 
      .sum(i_final), .strobe_out());
   
   add2_and_clip_reg #(.WIDTH(24)) add_clip_q
     (.clk(clk), .rst(rst), 
      .in1({adc_q_ofs,6'd0}), .in2({{4{corr_q[35]}},corr_q[35:16]}), .strobe_in(1'b1),
      .sum(q_final), .strobe_out());

   assign i_out = i_final;
   assign q_out = q_final;
   
   /*
   round_sd #(.WIDTH_IN(24),.WIDTH_OUT(18)) round_i
     (.clk(clk), .reset(rst), .in(i_final), .strobe_in(1'b1), .out(i_out), .strobe_out());
   
   round_sd #(.WIDTH_IN(24),.WIDTH_OUT(18)) round_q
     (.clk(clk), .reset(rst), .in(q_final), .strobe_in(1'b1), .out(q_out), .strobe_out());
   */
endmodule // rx_frontend