power_trig: first cut at power trigger with fixed delay

2 files changed, 115 insertions, 2 deletions

diff --git a/usrp2/custom/power_trig.v b/usrp2/custom/power_trig.v
new file mode 100644
index 000000000..ca213e901
--- /dev/null
+++ b/usrp2/custom/power_trig.v
@@ -0,0 +1,115 @@
+//
+// Copyright 2012 Ettus Research LLC
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+
+//CUSTOMIZE ME!
+
+//The following module effects the IO of the DDC chain.
+//By default, this entire module is a simple pass-through.
+
+//To implement DSP logic before the DDC:
+//Implement custom DSP between frontend and ddc input.
+
+//To implement DSP logic after the DDC:
+//Implement custom DSP between ddc output and baseband.
+
+//To bypass the DDC with custom logic:
+//Implement custom DSP between frontend and baseband.
+
+module power_trig
+  #(parameter BASE=0)
+   (//control signals
+    input clk, input reset, input enable,
+
+    // Setting Bus
+    input set_stb, input [7:0] set_addr, input [31:0] set_data,
+
+    input run,
+    
+    //strobed samples {I16,Q16} from the RX DDC chain
+    input [31:0] ddc_out_sample,
+    input ddc_out_strobe, //high on valid sample
+
+    //strobed baseband samples {I16,Q16} from this module
+    output [31:0] bb_sample,
+    output bb_strobe, //high on valid sample
+
+    //debug output (optional)
+    output [31:0] debug
+    );
+
+   reg [8:0] 	  wr_addr;
+   wire [8:0] 	  rd_addr;
+   reg 		  triggered, triggerable;
+   wire 	  trigger;
+   
+   wire [31:0] 	  delayed_sample;
+   wire [31:0] 	  thresh;
+   
+   setting_reg #(.my_addr(BASE+0)) sr_0
+     (.clk(clk),.rst(reset),.strobe(set_stb),.addr(set_addr),
+      .in(set_data),.out(thresh),.changed());
+
+   assign rd_addr = wr_addr + 1; // FIXME adjustable delay
+
+   ram_2port  #(.DWIDTH(32),.AWIDTH(9)) delay_line
+     (.clka(clk),.ena(1),.wea(ddc_out_strobe),.addra(wr_addr),.dia(ddc_out_sample),.doa(),
+      .clkb(clk),.enb(ddc_out_strobe),.web(1'b0),.addrb(rd_addr),.dib(32'hFFFF),.dob(delayed_sample));
+
+   always @(posedge clk)
+     if(reset | ~run)
+       wr_addr <= 0;
+     else
+       if(ddc_out_strobe)
+	 wr_addr <= wr_addr + 1;
+
+   always @(posedge clk)
+     if(reset | ~run)
+       triggerable <= 0;
+     else if(wr_addr == 9'h1FF)  // Wait till we're nearly full
+       triggerable <= 1;
+   
+
+   reg 			      stb_d1, stb_d2;
+   always @(posedge clk) stb_d1 <= ddc_out_strobe;
+   always @(posedge clk) stb_d2 <= stb_d1;
+   
+   assign bb_sample = delayed_sample;
+   assign bb_strobe = stb_d1 & triggered;
+
+   // Compute Mag
+   wire [17:0] 		      mult_in = stb_d1 ? { ddc_out_sample[15],ddc_out_sample[15:0], 1'b0 } : 
+			      { ddc_out_sample[31], ddc_out_sample[31:16], 1'b0 };
+   wire [35:0] 		      prod;
+   reg [31:0] 		      sum;
+   
+   MULT18X18S mult (.P(prod), .A(mult_in), .B(mult_in), .C(clk), .CE(ddc_out_strobe | stb_d1), .R(reset) );
+
+   always @(posedge clk)
+     if(stb_d1)
+       sum <= prod[35:4];
+     else if(stb_d2)
+       sum <= sum + prod[35:4];
+
+   always @(posedge clk)
+     if(reset | ~run | ~triggerable)
+       triggered <= 0;
+     else if(trigger)
+       triggered <= 1;
+
+   assign trigger = (sum > thresh);
+   
+endmodule // power_trig
diff --git a/usrp2/sdr_lib/cordic_z24.v b/usrp2/sdr_lib/cordic_z24.v
index 97b7beaf7..51b074a33 100644
--- a/usrp2/sdr_lib/cordic_z24.v
+++ b/usrp2/sdr_lib/cordic_z24.v
@@ -119,8 +119,6 @@ module cordic_z24(clock, reset, enable, xi, yi, zi, xo, yo, zo );
    assign xo = x20[bitwidth:1];  
    assign yo = y20[bitwidth:1];
    assign zo = z20;		  
-   //assign xo = x20[bitwidth+1:2];  // CORDIC gain is ~1.6, plus gain from rotating vectors
-   //assign yo = y20[bitwidth+1:2];
 
 endmodule // cordic