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authorJosh Blum <josh@joshknows.com>2010-01-22 11:56:55 -0800
committerJosh Blum <josh@joshknows.com>2010-01-22 11:56:55 -0800
commit7bf8a6df381a667134b55701993c6770d32bc76b (patch)
tree4a298fb5450f7277b5aaf5210740ae18f818c9aa /usrp2/sdr_lib/dsp_core_tx.v
parent8f2c33eab9396185df259639082b7d1618585973 (diff)
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Moved usrp2 fpga files into usrp2 subdir.
Diffstat (limited to 'usrp2/sdr_lib/dsp_core_tx.v')
-rw-r--r--usrp2/sdr_lib/dsp_core_tx.v152
1 files changed, 152 insertions, 0 deletions
diff --git a/usrp2/sdr_lib/dsp_core_tx.v b/usrp2/sdr_lib/dsp_core_tx.v
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+++ b/usrp2/sdr_lib/dsp_core_tx.v
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+
+`define DSP_CORE_TX_BASE 128
+
+module dsp_core_tx
+ (input clk, input rst,
+ input set_stb, input [7:0] set_addr, input [31:0] set_data,
+
+ output reg [15:0] dac_a,
+ output reg [15:0] dac_b,
+
+ // To tx_control
+ input [31:0] sample,
+ input run,
+ output strobe,
+ output [31:0] debug
+ );
+
+ wire [15:0] i, q, scale_i, scale_q;
+ wire [31:0] phase_inc;
+ reg [31:0] phase;
+ wire [7:0] interp_rate;
+ wire [3:0] dacmux_a, dacmux_b;
+ wire enable_hb1, enable_hb2;
+
+ setting_reg #(.my_addr(`DSP_CORE_TX_BASE+0)) sr_0
+ (.clk(clk),.rst(rst),.strobe(set_stb),.addr(set_addr),
+ .in(set_data),.out(phase_inc),.changed());
+
+ setting_reg #(.my_addr(`DSP_CORE_TX_BASE+1)) sr_1
+ (.clk(clk),.rst(rst),.strobe(set_stb),.addr(set_addr),
+ .in(set_data),.out({scale_i,scale_q}),.changed());
+
+ setting_reg #(.my_addr(`DSP_CORE_TX_BASE+2)) sr_2
+ (.clk(clk),.rst(rst),.strobe(set_stb),.addr(set_addr),
+ .in(set_data),.out({enable_hb1, enable_hb2, interp_rate}),.changed());
+
+ setting_reg #(.my_addr(`DSP_CORE_TX_BASE+4)) sr_4
+ (.clk(clk),.rst(rst),.strobe(set_stb),.addr(set_addr),
+ .in(set_data),.out({dacmux_b,dacmux_a}),.changed());
+
+ // Strobes are all now delayed by 1 cycle for timing reasons
+ wire strobe_cic_pre, strobe_hb1_pre, strobe_hb2_pre;
+ reg strobe_cic = 1;
+ reg strobe_hb1 = 1;
+ reg strobe_hb2 = 1;
+
+ cic_strober #(.WIDTH(8))
+ cic_strober(.clock(clk),.reset(rst),.enable(run),.rate(interp_rate),
+ .strobe_fast(1),.strobe_slow(strobe_cic_pre) );
+ cic_strober #(.WIDTH(2))
+ hb2_strober(.clock(clk),.reset(rst),.enable(run),.rate(enable_hb2 ? 2 : 1),
+ .strobe_fast(strobe_cic_pre),.strobe_slow(strobe_hb2_pre) );
+ cic_strober #(.WIDTH(2))
+ hb1_strober(.clock(clk),.reset(rst),.enable(run),.rate(enable_hb1 ? 2 : 1),
+ .strobe_fast(strobe_hb2_pre),.strobe_slow(strobe_hb1_pre) );
+
+ always @(posedge clk) strobe_hb1 <= strobe_hb1_pre;
+ always @(posedge clk) strobe_hb2 <= strobe_hb2_pre;
+ always @(posedge clk) strobe_cic <= strobe_cic_pre;
+
+ // NCO
+ always @(posedge clk)
+ if(rst)
+ phase <= 0;
+ else if(~run)
+ phase <= 0;
+ else
+ phase <= phase + phase_inc;
+
+ wire signed [17:0] da, db;
+ wire signed [35:0] prod_i, prod_q;
+
+ wire [17:0] bb_i = {sample[31:16],2'b0};
+ wire [17:0] bb_q = {sample[15:0],2'b0};
+ wire [17:0] i_interp, q_interp;
+
+ wire [17:0] hb1_i, hb1_q, hb2_i, hb2_q;
+
+ wire [7:0] cpo = enable_hb2 ? ({interp_rate,1'b0}) : interp_rate;
+ // Note that max CIC rate is 128, which would give an overflow on cpo if enable_hb2 is true,
+ // but the default case inside hb_interp handles this
+
+ hb_interp #(.IWIDTH(18),.OWIDTH(18),.ACCWIDTH(24)) hb_interp_i
+ (.clk(clk),.rst(rst),.bypass(~enable_hb1),.cpo(cpo),.stb_in(strobe_hb1),.data_in(bb_i),.stb_out(strobe_hb2),.data_out(hb1_i));
+ hb_interp #(.IWIDTH(18),.OWIDTH(18),.ACCWIDTH(24)) hb_interp_q
+ (.clk(clk),.rst(rst),.bypass(~enable_hb1),.cpo(cpo),.stb_in(strobe_hb1),.data_in(bb_q),.stb_out(strobe_hb2),.data_out(hb1_q));
+
+ small_hb_int #(.WIDTH(18)) small_hb_interp_i
+ (.clk(clk),.rst(rst),.bypass(~enable_hb2),.stb_in(strobe_hb2),.data_in(hb1_i),
+ .output_rate(interp_rate),.stb_out(strobe_cic),.data_out(hb2_i));
+ small_hb_int #(.WIDTH(18)) small_hb_interp_q
+ (.clk(clk),.rst(rst),.bypass(~enable_hb2),.stb_in(strobe_hb2),.data_in(hb1_q),
+ .output_rate(interp_rate),.stb_out(strobe_cic),.data_out(hb2_q));
+
+ cic_interp #(.bw(18),.N(4),.log2_of_max_rate(7))
+ cic_interp_i(.clock(clk),.reset(rst),.enable(run),.rate(interp_rate),
+ .strobe_in(strobe_cic),.strobe_out(1),
+ .signal_in(hb2_i),.signal_out(i_interp));
+
+ cic_interp #(.bw(18),.N(4),.log2_of_max_rate(7))
+ cic_interp_q(.clock(clk),.reset(rst),.enable(run),.rate(interp_rate),
+ .strobe_in(strobe_cic),.strobe_out(1),
+ .signal_in(hb2_q),.signal_out(q_interp));
+
+ assign strobe = strobe_hb1;
+
+ localparam cwidth = 24; // was 18
+ localparam zwidth = 24; // was 16
+
+ wire [cwidth-1:0] da_c, db_c;
+
+ cordic_z24 #(.bitwidth(cwidth))
+ cordic(.clock(clk), .reset(rst), .enable(run),
+ .xi({i_interp,{(cwidth-18){1'b0}}}),.yi({q_interp,{(cwidth-18){1'b0}}}),
+ .zi(phase[31:32-zwidth]),
+ .xo(da_c),.yo(db_c),.zo() );
+
+ MULT18X18S MULT18X18S_inst
+ (.P(prod_i), // 36-bit multiplier output
+ .A(da_c[cwidth-1:cwidth-18]), // 18-bit multiplier input
+ .B({{2{scale_i[15]}},scale_i}), // 18-bit multiplier input
+ .C(clk), // Clock input
+ .CE(1), // Clock enable input
+ .R(rst) // Synchronous reset input
+ );
+
+ MULT18X18S MULT18X18S_inst_2
+ (.P(prod_q), // 36-bit multiplier output
+ .A(db_c[cwidth-1:cwidth-18]), // 18-bit multiplier input
+ .B({{2{scale_q[15]}},scale_q}), // 18-bit multiplier input
+ .C(clk), // Clock input
+ .CE(1), // Clock enable input
+ .R(rst) // Synchronous reset input
+ );
+
+ always @(posedge clk)
+ case(dacmux_a)
+ 0 : dac_a <= prod_i[28:13];
+ 1 : dac_a <= prod_q[28:13];
+ default : dac_a <= 0;
+ endcase // case(dacmux_a)
+
+ always @(posedge clk)
+ case(dacmux_b)
+ 0 : dac_b <= prod_i[28:13];
+ 1 : dac_b <= prod_q[28:13];
+ default : dac_b <= 0;
+ endcase // case(dacmux_b)
+
+ assign debug = {strobe_cic, strobe_hb1, strobe_hb2,run};
+
+endmodule // dsp_core