Merge branch 'master' into udp

1 files changed, 90 insertions, 0 deletions

diff --git a/usrp1/sdr_lib/cic_interp.v b/usrp1/sdr_lib/cic_interp.v
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+++ b/usrp1/sdr_lib/cic_interp.v
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+// -*- verilog -*-
+//
+//  USRP - Universal Software Radio Peripheral
+//
+//  Copyright (C) 2003 Matt Ettus
+//
+//  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 2 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, write to the Free Software
+//  Foundation, Inc., 51 Franklin Street, Boston, MA  02110-1301  USA
+//
+
+
+module cic_interp(clock,reset,enable,rate,strobe_in,strobe_out,signal_in,signal_out);
+   parameter bw = 16;
+   parameter N = 4;
+   parameter log2_of_max_rate = 7;
+   parameter maxbitgain = (N-1)*log2_of_max_rate;
+   
+   input clock;
+   input reset;
+   input enable;
+   input [7:0] rate;
+   input strobe_in,strobe_out;	
+   input [bw-1:0] signal_in;
+   wire [bw-1:0] 	signal_in;
+   output [bw-1:0] signal_out;
+   wire [bw-1:0]   signal_out;
+
+   wire [bw+maxbitgain-1:0] signal_in_ext;
+   reg [bw+maxbitgain-1:0] integrator [0:N-1];
+   reg [bw+maxbitgain-1:0] differentiator [0:N-1];
+   reg [bw+maxbitgain-1:0] pipeline [0:N-1];
+
+   integer i;
+
+   sign_extend #(bw,bw+maxbitgain) 
+      ext_input (.in(signal_in),.out(signal_in_ext));
+
+   wire    clear_me = reset | ~enable;
+   //FIXME Note that this section has pipe and diff reversed
+   // It still works, but is confusing
+   always @(posedge clock)
+     if(clear_me)
+       for(i=0;i<N;i=i+1)
+	 integrator[i] <= #1 0;
+     else if (enable & strobe_out)
+       begin
+	  if(strobe_in)
+	    integrator[0] <= #1 integrator[0] + pipeline[N-1];
+	  for(i=1;i<N;i=i+1)
+	    integrator[i] <= #1 integrator[i] + integrator[i-1];
+       end
+   
+   always @(posedge clock)
+     if(clear_me)
+       begin
+	  for(i=0;i<N;i=i+1)
+	    begin
+	       differentiator[i] <= #1 0;
+	       pipeline[i] <= #1 0;
+ 	    end
+       end
+     else if (enable && strobe_in)
+       begin
+	  differentiator[0] <= #1 signal_in_ext;
+	  pipeline[0] <= #1 signal_in_ext - differentiator[0];
+	  for(i=1;i<N;i=i+1)
+	    begin
+	       differentiator[i] <= #1 pipeline[i-1];
+	       pipeline[i] <= #1 pipeline[i-1] - differentiator[i];
+	    end
+       end
+   
+   wire [bw+maxbitgain-1:0] signal_out_unnorm = integrator[N-1];
+
+   cic_int_shifter #(bw)
+	cic_int_shifter(rate,signal_out_unnorm,signal_out);
+   
+endmodule // cic_interp
+