Merged r10770:10887 from jcorgan/iad2 into trunk. Adds alternative USRP2 FPGA build to use integrate-and-dump decimator instead of CIC/HB combination. This provides a much shorter time duration impulse response for the same decimation rate, at the expense of worse stop-band rejection.

git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@10888 221aa14e-8319-0410-a670-987f0aec2ac5

8 files changed, 776 insertions, 0 deletions

diff --git a/top/u2_rev3_iad/Makefile b/top/u2_rev3_iad/Makefile
new file mode 100644
index 000000000..24dffd92b
--- /dev/null
+++ b/top/u2_rev3_iad/Makefile
@@ -0,0 +1,254 @@
+#
+# Copyright 2008 Ettus Research LLC
+# 
+# This file is part of GNU Radio
+# 
+# GNU Radio 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, or (at your option)
+# any later version.
+# 
+# GNU Radio 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 GNU Radio; see the file COPYING.  If not, write to
+# the Free Software Foundation, Inc., 51 Franklin Street,
+# Boston, MA 02110-1301, USA.
+# 
+
+##################################################
+# xtclsh Shell and tcl Script Path
+##################################################
+#XTCLSH := /opt/Xilinx/10.1/ISE/bin/lin/xtclsh
+XTCLSH := xtclsh
+ISE_HELPER := ../tcl/ise_helper.tcl
+
+##################################################
+# Project Setup
+##################################################
+BUILD_DIR := build/
+export TOP_MODULE := u2_rev3
+export PROJ_FILE := $(BUILD_DIR)$(TOP_MODULE).ise
+
+##################################################
+# Project Properties
+##################################################
+export PROJECT_PROPERTIES := \
+family Spartan3 \
+device xc3s2000 \
+package fg456 \
+speed -5 \
+top_level_module_type "HDL" \
+synthesis_tool "XST (VHDL/Verilog)" \
+simulator "ISE Simulator (VHDL/Verilog)" \
+"Preferred Language" "Verilog" \
+"Enable Message Filtering" FALSE \
+"Display Incremental Messages" FALSE 
+
+##################################################
+# Sources
+##################################################
+export SOURCE_ROOT := ../../../
+export SOURCES := \
+control_lib/CRC16_D16.v \
+control_lib/atr_controller.v \
+control_lib/bin2gray.v \
+control_lib/buffer_int.v \
+control_lib/buffer_pool.v \
+control_lib/cascadefifo2.v \
+control_lib/dcache.v \
+control_lib/decoder_3_8.v \
+control_lib/dpram32.v \
+control_lib/fifo_2clock.v \
+control_lib/fifo_2clock_casc.v \
+control_lib/gray2bin.v \
+control_lib/gray_send.v \
+control_lib/icache.v \
+control_lib/longfifo.v \
+control_lib/mux4.v \
+control_lib/mux8.v \
+control_lib/nsgpio.v \
+control_lib/ram_2port.v \
+control_lib/ram_harv_cache.v \
+control_lib/ram_loader.v \
+control_lib/setting_reg.v \
+control_lib/settings_bus.v \
+control_lib/shortfifo.v \
+control_lib/medfifo.v \
+control_lib/srl.v \
+control_lib/system_control.v \
+control_lib/wb_1master.v \
+control_lib/wb_readback_mux.v \
+control_lib/simple_uart.v \
+control_lib/simple_uart_tx.v \
+control_lib/simple_uart_rx.v \
+control_lib/oneshot_2clk.v \
+control_lib/sd_spi.v \
+control_lib/sd_spi_wb.v \
+control_lib/wb_bridge_16_32.v \
+coregen/fifo_xlnx_2Kx36_2clk.v \
+coregen/fifo_xlnx_2Kx36_2clk.xco \
+coregen/fifo_xlnx_512x36_2clk.v \
+coregen/fifo_xlnx_512x36_2clk.xco \
+eth/mac_rxfifo_int.v \
+eth/mac_txfifo_int.v \
+eth/rtl/verilog/Clk_ctrl.v \
+eth/rtl/verilog/MAC_rx.v \
+eth/rtl/verilog/MAC_rx/Broadcast_filter.v \
+eth/rtl/verilog/MAC_rx/CRC_chk.v \
+eth/rtl/verilog/MAC_rx/MAC_rx_FF.v \
+eth/rtl/verilog/MAC_rx/MAC_rx_add_chk.v \
+eth/rtl/verilog/MAC_rx/MAC_rx_ctrl.v \
+eth/rtl/verilog/MAC_top.v \
+eth/rtl/verilog/MAC_tx.v \
+eth/rtl/verilog/MAC_tx/CRC_gen.v \
+eth/rtl/verilog/MAC_tx/MAC_tx_FF.v \
+eth/rtl/verilog/MAC_tx/MAC_tx_addr_add.v \
+eth/rtl/verilog/MAC_tx/MAC_tx_ctrl.v \
+eth/rtl/verilog/MAC_tx/Random_gen.v \
+eth/rtl/verilog/Phy_int.v \
+eth/rtl/verilog/RMON.v \
+eth/rtl/verilog/RMON/RMON_addr_gen.v \
+eth/rtl/verilog/RMON/RMON_ctrl.v \
+eth/rtl/verilog/Reg_int.v \
+eth/rtl/verilog/eth_miim.v \
+eth/rtl/verilog/flow_ctrl_rx.v \
+eth/rtl/verilog/flow_ctrl_tx.v \
+eth/rtl/verilog/miim/eth_clockgen.v \
+eth/rtl/verilog/miim/eth_outputcontrol.v \
+eth/rtl/verilog/miim/eth_shiftreg.v \
+extram/wb_zbt16_b.v \
+opencores/8b10b/decode_8b10b.v \
+opencores/8b10b/encode_8b10b.v \
+opencores/aemb/rtl/verilog/aeMB_bpcu.v \
+opencores/aemb/rtl/verilog/aeMB_core_BE.v \
+opencores/aemb/rtl/verilog/aeMB_ctrl.v \
+opencores/aemb/rtl/verilog/aeMB_edk32.v \
+opencores/aemb/rtl/verilog/aeMB_ibuf.v \
+opencores/aemb/rtl/verilog/aeMB_regf.v \
+opencores/aemb/rtl/verilog/aeMB_xecu.v \
+opencores/i2c/rtl/verilog/i2c_master_bit_ctrl.v \
+opencores/i2c/rtl/verilog/i2c_master_byte_ctrl.v \
+opencores/i2c/rtl/verilog/i2c_master_defines.v \
+opencores/i2c/rtl/verilog/i2c_master_top.v \
+opencores/i2c/rtl/verilog/timescale.v \
+opencores/simple_pic/rtl/simple_pic.v \
+opencores/spi/rtl/verilog/spi_clgen.v \
+opencores/spi/rtl/verilog/spi_defines.v \
+opencores/spi/rtl/verilog/spi_shift.v \
+opencores/spi/rtl/verilog/spi_top.v \
+opencores/spi/rtl/verilog/timescale.v \
+sdr_lib/acc.v \
+sdr_lib/add2.v \
+sdr_lib/add2_and_round.v \
+sdr_lib/add2_and_round_reg.v \
+sdr_lib/add2_reg.v \
+sdr_lib/cic_dec_shifter.v \
+sdr_lib/cic_decim.v \
+sdr_lib/cic_int_shifter.v \
+sdr_lib/cic_interp.v \
+sdr_lib/cic_strober.v \
+sdr_lib/clip.v \
+sdr_lib/clip_reg.v \
+sdr_lib/cordic.v \
+sdr_lib/cordic_z24.v \
+sdr_lib/cordic_stage.v \
+sdr_lib/dsp_core_tx.v \
+sdr_lib/hb_dec.v \
+sdr_lib/hb_interp.v \
+sdr_lib/round.v \
+sdr_lib/round_reg.v \
+sdr_lib/rx_control.v \
+sdr_lib/rx_dcoffset.v \
+sdr_lib/sign_extend.v \
+sdr_lib/small_hb_dec.v \
+sdr_lib/small_hb_int.v \
+sdr_lib/tx_control.v \
+serdes/serdes.v \
+serdes/serdes_fc_rx.v \
+serdes/serdes_fc_tx.v \
+serdes/serdes_rx.v \
+serdes/serdes_tx.v \
+timing/time_receiver.v \
+timing/time_sender.v \
+timing/time_sync.v \
+timing/timer.v \
+top/u2_core/u2_core.v \
+top/u2_rev3/u2_rev3.ucf \
+top/u2_rev3/u2_rev3.v \
+top/u2_rev3_iad/dsp_core_rx.v \
+top/u2_rev3_iad/integrate.v
+
+##################################################
+# Process Properties
+##################################################
+export SYNTHESIZE_PROPERTIES := \
+"Number of Clock Buffers" 6 \
+"Pack I/O Registers into IOBs" Yes \
+"Optimization Effort" High \
+"Optimize Instantiated Primitives" TRUE \
+"Register Balancing" Yes \
+"Use Clock Enable" Auto \
+"Use Synchronous Reset" Auto \
+"Use Synchronous Set" Auto
+
+export TRANSLATE_PROPERTIES := \
+"Macro Search Path" "$(shell pwd)/../../coregen/"
+
+export MAP_PROPERTIES := \
+"Allow Logic Optimization Across Hierarchy" TRUE \
+"Map to Input Functions" 4 \
+"Optimization Strategy (Cover Mode)" Speed \
+"Pack I/O Registers/Latches into IOBs" "For Inputs and Outputs" \
+"Perform Timing-Driven Packing and Placement" TRUE \
+"Map Effort Level" High \
+"Extra Effort" Normal \
+"Combinatorial Logic Optimization" TRUE \
+"Register Duplication" TRUE
+
+export PLACE_ROUTE_PROPERTIES := \
+"Place & Route Effort Level (Overall)" High 
+
+export STATIC_TIMING_PROPERTIES := \
+"Number of Paths in Error/Verbose Report" 10 \
+"Report Type" "Error Report"
+
+export GEN_PROG_FILE_PROPERTIES := \
+"Configuration Rate" 6 \
+"Create Binary Configuration File" TRUE \
+"Done (Output Events)" 5 \
+"Enable Bitstream Compression" TRUE \
+"Enable Outputs (Output Events)" 6 
+
+export SIM_MODEL_PROPERTIES := ""
+
+##################################################
+# Make Options
+##################################################
+all:
+	@echo make proj, check, synth, bin, testbench, or clean
+
+proj:
+	PROCESS_RUN="" $(XTCLSH) $(ISE_HELPER)	
+
+check:
+	PROCESS_RUN="Check Syntax" $(XTCLSH) $(ISE_HELPER)	
+
+synth:
+	PROCESS_RUN="Synthesize - XST" $(XTCLSH) $(ISE_HELPER)	
+
+bin:
+	PROCESS_RUN="Generate Programming File" $(XTCLSH) $(ISE_HELPER)		
+
+testbench:
+	iverilog -c cmdfile -o dsp_core_tb dsp_core_tb.v
+
+clean:
+	rm -rf $(BUILD_DIR)
+	rm -f dsp_core_tb
+	rm -f *.lx2
+	rm -f *.dat
+	rm -f *.vcd
diff --git a/top/u2_rev3_iad/cmdfile b/top/u2_rev3_iad/cmdfile
new file mode 100644
index 000000000..34373a676
--- /dev/null
+++ b/top/u2_rev3_iad/cmdfile
@@ -0,0 +1,4 @@
+-y .
+-y ../../sdr_lib
+-y ../../control_lib
+-y ../../models
diff --git a/top/u2_rev3_iad/dsp_core_rx.v b/top/u2_rev3_iad/dsp_core_rx.v
new file mode 100644
index 000000000..0ad823cac
--- /dev/null
+++ b/top/u2_rev3_iad/dsp_core_rx.v
@@ -0,0 +1,157 @@
+`define DSP_CORE_RX_BASE 160
+module dsp_core_rx
+  (input clk, input rst,
+   input set_stb, input [7:0] set_addr, input [31:0] set_data,
+
+   input [13:0] adc_a, input adc_ovf_a,
+   input [13:0] adc_b, input adc_ovf_b,
+   
+   input [15:0] io_rx,
+
+   output [31:0] sample,
+   input run,
+   output strobe,
+   output [31:0] debug
+   );
+
+   wire [15:0] scale_i, scale_q;
+   wire [13:0] adc_a_ofs, adc_b_ofs;
+   reg [13:0] adc_i, adc_q;
+   wire [31:0] phase_inc;
+   reg [31:0]  phase;
+
+   wire [35:0] prod_i, prod_q;
+   wire [23:0] i_cordic, q_cordic;
+   wire [31:0] i_iad, q_iad;
+   wire [15:0] i_out, q_out;
+   
+   wire        enable_hb1, enable_hb2; // Correspond to std firmware settings
+   wire [7:0]  cic_decim;              // for combined CIC/HB decimator
+   wire [9:0]  decim_rate;             // Reconstructed original decimation setting
+   
+   setting_reg #(.my_addr(`DSP_CORE_RX_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_RX_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_RX_BASE+2)) sr_2
+     (.clk(clk),.rst(rst),.strobe(set_stb),.addr(set_addr),
+      .in(set_data),.out({enable_hb1,enable_hb2,cic_decim}),.changed());
+
+   rx_dcoffset #(.WIDTH(14),.ADDR(`DSP_CORE_RX_BASE+6)) rx_dcoffset_a
+     (.clk(clk),.rst(rst),.set_stb(set_stb),.set_addr(set_addr),.set_data(set_data),
+      .adc_in(adc_a),.adc_out(adc_a_ofs));
+   
+   rx_dcoffset #(.WIDTH(14),.ADDR(`DSP_CORE_RX_BASE+7)) rx_dcoffset_b
+     (.clk(clk),.rst(rst),.set_stb(set_stb),.set_addr(set_addr),.set_data(set_data),
+      .adc_in(adc_b),.adc_out(adc_b_ofs));
+
+   wire [3:0]  muxctrl;
+   setting_reg #(.my_addr(`DSP_CORE_RX_BASE+8)) sr_8
+     (.clk(clk),.rst(rst),.strobe(set_stb),.addr(set_addr),
+      .in(set_data),.out(muxctrl),.changed());
+
+   wire [1:0] gpio_ena;
+   setting_reg #(.my_addr(`DSP_CORE_RX_BASE+9)) sr_9
+     (.clk(clk),.rst(rst),.strobe(set_stb),.addr(set_addr),
+      .in(set_data),.out(gpio_ena),.changed());
+
+   // The TVRX connects to what is called adc_b, thus A and B are
+   // swapped throughout the design.
+   //
+   // In the interest of expediency and keeping the s/w sane, we just remap them here.
+   // The I & Q fields are mapped the same:
+   // 0 -> "the real A" (as determined by the TVRX)
+   // 1 -> "the real B"
+   // 2 -> const zero
+   
+   always @(posedge clk)
+     case(muxctrl[1:0])		// The I mapping
+       0: adc_i <= adc_b_ofs;	// "the real A"
+       1: adc_i <= adc_a_ofs;
+       2: adc_i <= 0;
+       default: adc_i <= 0;
+     endcase // case(muxctrl[1:0])
+          
+   always @(posedge clk)
+     case(muxctrl[3:2])		// The Q mapping
+       0: adc_q <= adc_b_ofs;	// "the real A"
+       1: adc_q <= adc_a_ofs;
+       2: adc_q <= 0;
+       default: adc_q <= 0;
+     endcase // case(muxctrl[3:2])
+       
+   always @(posedge clk)
+     if(rst)
+       phase <= 0;
+     else if(~run)
+       phase <= 0;
+     else
+       phase <= phase + phase_inc;
+
+   MULT18X18S mult_i
+     (.P(prod_i),    // 36-bit multiplier output
+      .A({{4{adc_i[13]}},adc_i} ),    // 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 mult_q
+     (.P(prod_q),    // 36-bit multiplier output
+      .A({{4{adc_q[13]}},adc_q} ),    // 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
+      ); 
+
+   
+   cordic_z24 #(.bitwidth(24))
+     cordic(.clock(clk), .reset(rst), .enable(run),
+	    .xi(prod_i[24:1]),. yi(prod_q[24:1]), .zi(phase[31:8]),
+	    .xo(i_cordic),.yo(q_cordic),.zo() );
+
+   // Reconstruct original decimation rate from standard firmware settings
+   assign decim_rate = enable_hb1 ? (enable_hb2 ? {cic_decim,2'b0} : {1'b0,cic_decim,1'b0 }) :
+				    cic_decim;
+
+   cic_strober #(.WIDTH(10)) // Convenient reuse of strobe generator
+   cic_strober(.clock(clk),.reset(rst),.enable(run),.rate(decim_rate),
+	       .strobe_fast(1),.strobe_slow(strobe_iad) );
+
+   integrate #(.INPUTW(24),.ACCUMW(32),.OUTPUTW(32)) integrator_i
+     (.clk_i(clk),.rst_i(rst),.ena_i(run),
+      .dump_i(strobe_iad),.data_i(i_cordic),
+      .stb_o(strobe),.integ_o(i_iad) );
+
+   integrate #(.INPUTW(24),.ACCUMW(32),.OUTPUTW(32)) integrator_q
+     (.clk_i(clk),.rst_i(rst),.ena_i(run),
+      .dump_i(strobe_iad),.data_i(q_cordic),
+      .stb_o(),.integ_o(q_iad) );
+   
+   round #(.bits_in(32),.bits_out(16)) round_iout (.in(i_iad),.out(i_out));
+   round #(.bits_in(32),.bits_out(16)) round_qout (.in(q_iad),.out(q_out));
+  
+   // Streaming GPIO
+   //
+   // io_rx[15] => I channel LSB if gpio_ena[0] high
+   // io_rx[14] => Q channel LSB if gpio_ena[1] high
+
+   reg [31:0] sample_reg;
+   always @(posedge clk)
+     begin
+	sample_reg[31:17] <= i_out[15:1];
+	sample_reg[15:1]  <= q_out[15:1];
+	sample_reg[16]    <= gpio_ena[0] ? io_rx[15] : i_out[0]; 
+	sample_reg[0]     <= gpio_ena[1] ? io_rx[14] : q_out[0];
+     end
+   
+   assign      sample = sample_reg;
+   assign      debug = {clk, rst, run, strobe};
+   
+endmodule // dsp_core_rx
diff --git a/top/u2_rev3_iad/dsp_core_tb.sav b/top/u2_rev3_iad/dsp_core_tb.sav
new file mode 100644
index 000000000..17c90cdd7
--- /dev/null
+++ b/top/u2_rev3_iad/dsp_core_tb.sav
@@ -0,0 +1,61 @@
+[size] 1680 975
+[pos] -1 -1
+*-24.007835 13660000 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1
+[treeopen] dsp_core_tb.
+@200
+-SYSCON
+@28
+dsp_core_tb.clk
+dsp_core_tb.rst
+dsp_core_tb.run
+@200
+-
+-Settings Bus
+@22
+dsp_core_tb.set_addr[7:0]
+@24
+dsp_core_tb.set_data[31:0]
+@28
+dsp_core_tb.set_stb
+@200
+-
+-RX DSP CORE
+-
+@24
+dsp_core_tb.rx_path.decim_rate[9:0]
+@200
+-
+@8420
+dsp_core_tb.adc_a[13:0]
+@20000
+-
+@200
+-
+@8420
+dsp_core_tb.rx_path.adc_a_ofs[13:0]
+@20000
+-
+@200
+-
+@8022
+dsp_core_tb.rx_path.i_cordic[23:0]
+@20000
+-
+@200
+-
+@8022
+dsp_core_tb.rx_path.i_iad[31:0]
+@20000
+-
+@200
+-
+@8420
+dsp_core_tb.rx_path.i_out[15:0]
+@20000
+-
+@200
+-
+@28
+dsp_core_tb.stb
+@200
+-
diff --git a/top/u2_rev3_iad/dsp_core_tb.v b/top/u2_rev3_iad/dsp_core_tb.v
new file mode 100644
index 000000000..6b4c1669b
--- /dev/null
+++ b/top/u2_rev3_iad/dsp_core_tb.v
@@ -0,0 +1,196 @@
+`timescale 1ns / 100ps
+
+module dsp_core_tb;
+
+///////////////////////////////////////////////////////////////////////////////////
+// Sim-wide wires/busses                                                         //
+///////////////////////////////////////////////////////////////////////////////////
+   
+   // System control bus
+   reg                clk = 0;
+   reg                rst = 1;
+   
+   // Configuration bus
+   reg                set_stb = 0;  
+   reg          [7:0] set_addr = 0; 
+   reg         [31:0] set_data = 0; 
+
+   // ADC input bus
+   wire signed [13:0] adc_a;
+   wire signed [13:0] adc_b;
+   wire               adc_ovf_a;
+   wire               adc_ovf_b;
+   
+   // RX sample bus
+   reg                run = 1;
+   wire        [31:0] sample;
+   wire               stb;
+   
+///////////////////////////////////////////////////////////////////////////////////
+// Simulation control                                                            //
+///////////////////////////////////////////////////////////////////////////////////
+   
+   // Set up output files
+   initial begin
+      $dumpfile("dsp_core_tb.vcd");
+      $dumpvars(0,dsp_core_tb);
+   end
+
+   // Update display every 10 us
+   always #1000 $monitor("Time in us ",$time/1000);
+
+   // Generate master clock 50% @ 100 MHz
+   always
+     #5 clk = ~clk;
+
+///////////////////////////////////////////////////////////////////////////////////
+// Unit(s) under test                                                            //
+///////////////////////////////////////////////////////////////////////////////////
+   
+   reg [13:0] amplitude = 13'h1fff;
+   reg [15:0] impulse_len = 0;
+   reg [15:0] zero_len = 0;
+   reg 	      adc_ena = 0;
+
+   initial #500 @(posedge clk) adc_ena = 1;
+
+   impulse adc
+     (.clk(clk),.rst(rst),.ena(adc_ena),
+      .dc_offset_a(0),.dc_offset_b(0),
+      .amplitude(amplitude),
+      .impulse_len(impulse_len),.zero_len(zero_len),
+      .adc_a(adc_a),.adc_b(adc_b),
+      .adc_ovf_a(adc_ovf_a),.adc_ovf_b(adc_ovf_b) );
+
+   initial rx_path.rx_dcoffset_a.integrator = 0; // so sim doesn't propagate X's
+   initial rx_path.rx_dcoffset_b.integrator = 0; // generated before reset
+   dsp_core_rx rx_path
+     (.clk(clk),.rst(rst),
+      .set_stb(set_stb),.set_addr(set_addr),.set_data(set_data),
+      .adc_a(adc_a),.adc_ovf_a(adc_ovf_a),
+      .adc_b(adc_b),.adc_ovf_b(adc_ovf_b),
+      .io_rx(16'b0),
+      .run(adc_ena),.sample(sample),.strobe(stb),
+      .debug() );
+   
+///////////////////////////////////////////////////////////////////////////////////
+// Simulation output/checking                                                    //
+///////////////////////////////////////////////////////////////////////////////////
+
+   integer rx_file;
+   
+   initial
+     rx_file = $fopen("rx.dat", "wb");
+   
+   always @(posedge clk)
+     begin
+	// Write RX sample I&Q in format Octave can load
+	if (stb)
+	  begin
+	     $fwrite(rx_file, sample[31:16]);
+	     $fputc(32, rx_file);
+	     $fwrite(rx_file, sample[15:0]);
+	     $fputc(13, rx_file);
+	  end
+     end
+   
+///////////////////////////////////////////////////////////////////////////////////
+// Tasks                                                                         //
+///////////////////////////////////////////////////////////////////////////////////
+
+   task power_on;
+     begin
+	@(posedge clk)
+	  rst = #1 1'b1;
+	@(posedge clk)
+	  rst = #1 1'b0;
+     end
+   endtask // power_on
+   
+   task set_impulse_len;
+      input [15:0] len;
+      @(posedge clk) impulse_len = len-1;
+   endtask
+ 
+   task set_zero_len;
+      input [15:0] len;
+      @(posedge clk) zero_len = len-1;
+   endtask
+
+   // Strobe configuration bus with addr, data
+   task write_cfg_register;
+      input [7:0]  regno;
+      input [31:0] value;
+      
+      begin
+	 @(posedge clk);
+	 set_addr <= regno;
+	 set_data <= value;
+	 set_stb  <= 1'b1;
+	 @(posedge clk);
+	 set_stb  <= 1'b0;
+      end
+   endtask // write_cfg_register
+
+   // Set RX DDC frequency
+   task set_ddc_freq;
+      input [31:0] freq;
+
+      write_cfg_register(160, freq);
+   endtask // set_ddc_freq
+
+   // Set RX IQ scaling registers
+   task set_rx_scale_iq;
+      input [15:0] scale_i;
+      input [15:0] scale_q;
+
+      write_cfg_register(161, {scale_i,scale_q});
+   endtask // set_rx_scale_iq
+   
+   // Set RX MUX control
+   task set_rx_muxctrl;
+      input [3:0] muxctrl;
+
+      write_cfg_register(168, muxctrl);
+   endtask // set_rx_muxctrl
+   
+   // Set RX CIC decim and halfband enables
+   task set_decim;
+      input hb1_ena;
+      input hb2_ena;
+      input [7:0] decim;
+
+      write_cfg_register(162, {hb1_ena,hb2_ena,decim});
+   endtask // set_decim
+      
+   
+///////////////////////////////////////////////////////////////////////////////////
+// Individual tests                                                              //
+///////////////////////////////////////////////////////////////////////////////////
+
+   task test_rx;
+      begin
+	 set_impulse_len(1);
+	 set_zero_len(999);
+	 set_rx_muxctrl(1);
+	 set_ddc_freq(0);
+	 set_rx_scale_iq(1243, 1243);
+	 set_decim(1, 1, 10);
+
+	 #100000 $finish;
+      end
+   endtask // test_rx
+   
+      
+///////////////////////////////////////////////////////////////////////////////////
+// Top-level test                                                                //
+///////////////////////////////////////////////////////////////////////////////////
+
+   // Execute tests
+   initial
+     begin
+	power_on();
+	test_rx();
+     end
+
+endmodule // dsp_core_tb
diff --git a/top/u2_rev3_iad/impulse.v b/top/u2_rev3_iad/impulse.v
new file mode 100644
index 000000000..ecdf101ab
--- /dev/null
+++ b/top/u2_rev3_iad/impulse.v
@@ -0,0 +1,63 @@
+module impulse
+  (input clk,
+   input rst,
+   input ena,
+   
+   input [13:0] dc_offset_a,
+   input [13:0] dc_offset_b,
+   input [13:0] amplitude,
+   input [15:0] impulse_len,
+   input [15:0] zero_len,
+
+   output [13:0] adc_a,
+   output [13:0] adc_b,
+   output        adc_ovf_a,
+   output        adc_ovf_b
+   );
+
+   reg [13:0] adc_a_int = 0;
+   reg [15:0] count;
+
+   localparam ST_ZERO = 0;
+   localparam ST_HIGH = 1;
+   reg 	      state;
+   
+   always @(posedge clk)
+     if (rst | ~ena)
+       begin
+	  adc_a_int <= 0;
+	  count <= 0;
+	  state <= ST_ZERO;
+       end
+     else
+       case(state)
+	 ST_ZERO:
+	   if (count == zero_len)
+	     begin
+		adc_a_int <= amplitude;
+		state <= ST_HIGH;
+		count <= 0;
+	     end
+	   else
+	     count <= count + 1;
+
+	 ST_HIGH:
+	   if (count == impulse_len)
+	     begin
+		adc_a_int <= 0;
+		state <= ST_ZERO;
+		count <= 0;
+	     end
+	   else
+	     count <= count + 1;
+
+       endcase // case (state)
+
+   assign adc_a = adc_a_int + dc_offset_a;
+
+   // Ignore for now
+   assign adc_b = dc_offset_b;
+   assign adc_ovf_a = 0;
+   assign adc_ovf_b = 0;
+
+endmodule // adc_model
diff --git a/top/u2_rev3_iad/integrate.v b/top/u2_rev3_iad/integrate.v
new file mode 100644
index 000000000..db33de979
--- /dev/null
+++ b/top/u2_rev3_iad/integrate.v
@@ -0,0 +1,38 @@
+module integrate
+  #(parameter INPUTW = 16,
+    parameter ACCUMW = 32,
+    parameter OUTPUTW = 16)
+
+   (input clk_i,
+    input rst_i,
+    input ena_i,
+
+    input dump_i,
+    input [INPUTW-1:0] data_i,
+
+    output reg stb_o,
+    output reg [OUTPUTW-1:0] integ_o
+   );
+   
+   wire [ACCUMW-1:0] data_ext = {{ACCUMW-INPUTW{data_i[INPUTW-1]}},data_i};
+   reg  [ACCUMW-1:0] accum;
+
+   always @(posedge clk_i)
+     if (rst_i | ~ena_i)
+       begin
+	  accum <= 0;
+	  integ_o <= 0;
+       end
+     else
+       if (dump_i)
+	 begin
+	    integ_o <= accum[ACCUMW-1:ACCUMW-OUTPUTW];
+	    accum <= data_ext;
+	 end
+       else
+	 accum <= accum + data_ext;
+
+   always @(posedge clk_i)
+     stb_o <= dump_i;
+   
+endmodule // integrate
diff --git a/top/u2_rev3_iad/wave.sh b/top/u2_rev3_iad/wave.sh
new file mode 100755
index 000000000..626f224e5
--- /dev/null
+++ b/top/u2_rev3_iad/wave.sh
@@ -0,0 +1,3 @@
+#!/bin/sh
+
+gtkwave dsp_core_tb.vcd dsp_core_tb.sav &