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module tx_frontend
#(parameter BASE=0)
(input clk, input rst,
input set_stb, input [7:0] set_addr, input [31:0] set_data,
input [23:0] tx_i, input [23:0] tx_q, input run,
output reg [15:0] dac_a, output reg [15:0] dac_b
);
// IQ balance --> DC offset --> rounding --> mux
wire [23:0] i_dco, q_dco, i_ofs, q_ofs;
wire [15:0] i_final, q_final;
wire [7:0] mux_ctrl;
setting_reg #(.my_addr(BASE+0), .width(24)) sr_0
(.clk(clk),.rst(rst),.strobe(set_stb),.addr(set_addr),
.in(set_data),.out(i_dco),.changed());
setting_reg #(.my_addr(BASE+1), .width(24)) sr_1
(.clk(clk),.rst(rst),.strobe(set_stb),.addr(set_addr),
.in(set_data),.out(q_dco),.changed());
setting_reg #(.my_addr(BASE+2), .width(4)) sr_2
(.clk(clk),.rst(rst),.strobe(set_stb),.addr(set_addr),
.in(set_data),.out(mux_ctrl),.changed());
add2_and_clip_reg #(.WIDTH(24)) add_dco_i
(.clk(clk), .rst(rst), .in1(i_dco), .in2(tx_i), .strobe_in(1'b1), .sum(i_ofs), .strobe_out());
add2_and_clip_reg #(.WIDTH(24)) add_dco_q
(.clk(clk), .rst(rst), .in1(q_dco), .in2(tx_q), .strobe_in(1'b1), .sum(q_ofs), .strobe_out());
round_sd #(.WIDTH_IN(24),.WIDTH_OUT(16)) round_i
(.clk(clk), .reset(rst), .in(i_ofs),.strobe_in(1'b1), .out(i_final), .strobe_out());
round_sd #(.WIDTH_IN(24),.WIDTH_OUT(16)) round_q
(.clk(clk), .reset(rst), .in(q_ofs),.strobe_in(1'b1), .out(q_final), .strobe_out());
always @(posedge clk)
case(mux_ctrl[3:0])
0 : dac_a <= i_final;
1 : dac_a <= q_final;
default : dac_a <= 0;
endcase // case (mux_ctrl[3:0])
always @(posedge clk)
case(mux_ctrl[7:4])
0 : dac_b <= i_final;
1 : dac_b <= q_final;
default : dac_b <= 0;
endcase // case (mux_ctrl[7:4])
endmodule // tx_frontend
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