1 files changed, 31 insertions, 43 deletions

diff --git a/gr-sounder/src/fpga/lib/sounder_rx.v b/gr-sounder/src/fpga/lib/sounder_rx.v
index 338afd55e..18038a3a1 100644
--- a/gr-sounder/src/fpga/lib/sounder_rx.v
+++ b/gr-sounder/src/fpga/lib/sounder_rx.v
@@ -19,75 +19,63 @@
 //  Foundation, Inc., 51 Franklin Street, Boston, MA  02110-1301  USA
 //
 
-module sounder_rx(clk_i,rst_i,ena_i,rx_strobe_i,tx_strobe_i,mask_i,degree_i,len_i,
-		  rx_in_i_i,rx_in_q_i,rx_i_o,rx_q_o,rx_strobe_o,
-		  loop_i);
+module sounder_rx(clk_i,rst_i,ena_i,sum_strobe_i,ref_strobe_i,
+		  mask_i,degree_i,rx_in_i_i,rx_in_q_i,rx_i_o,rx_q_o);
    
    input         clk_i;		// Master clock
    input         rst_i;         // Subsystem reset
    input         ena_i;		// Subsystem enable
-   input         rx_strobe_i;   // Strobe every received sample
-   input         tx_strobe_i;	// Strobe every transmitted sample
+   input         sum_strobe_i;  // Strobe on last sample per period
+   input         ref_strobe_i;  // PN code reference retarded one sample per period
     
    input  [15:0] mask_i;	// PN code LFSR mask
    input  [4:0]  degree_i;	// PN code LFSR sequency degree
-   input  [15:0] len_i;		// PN code LFSR sequence length
+   
    input  [15:0] rx_in_i_i;	// I channel on receive
    input  [15:0] rx_in_q_i;	// Q channel on receive
 
    output [15:0] rx_i_o;	// I channel of impulse response
    output [15:0] rx_q_o;	// Q channel of impulse response
-   output        rx_strobe_o;   // Impulse response value ready
-
-   input         loop_i;        // Implement loopback
-   
-   wire strobe_in  = loop_i ? tx_strobe_i : rx_strobe_i;
-   wire [16:0] len = loop_i ? (len_i - 1) : ((len_i << 1) - 2);
-		 
-   strobe #(17) phase_strobe(.clk_i(clk_i),.rst_i(rst_i),.ena_i(ena_i),
-		       .rate_i(len),.strobe_i(strobe_in),.strobe_o(rx_strobe_o),
-		       .count_o());
-
-   wire pn_ref;
-   wire ref_strobe = tx_strobe_i & ~rx_strobe_o; // Retard reference phase once per period
-   lfsr ref_code
-     ( .clk_i(clk_i),.rst_i(rst_i),.ena_i(ena_i),.strobe_i(ref_strobe),.mask_i(mask_i),.pn_o(pn_ref) );
 
-   wire [5:0] offset = (5'd16-degree_i);
-   
    reg  [31:0] sum_i, sum_q;
    reg  [31:0] total_i, total_q;
-   wire [31:0] scaled_i = total_i << offset;
-   wire [31:0] scaled_q = total_q << offset;
    wire [31:0] i_ext, q_ext;
 
    sign_extend #(16,32) i_extender(rx_in_i_i, i_ext);
    sign_extend #(16,32) q_extender(rx_in_q_i, q_ext);
 
+   wire pn_ref;
+   lfsr ref_code
+     ( .clk_i(clk_i),.rst_i(rst_i),.ena_i(ena_i),.strobe_i(ref_strobe_i),.mask_i(mask_i),.pn_o(pn_ref) );
+
    wire [31:0] prod_i = pn_ref ? i_ext : -i_ext;
    wire [31:0] prod_q = pn_ref ? q_ext : -q_ext;
-   
+
    always @(posedge clk_i)
      if (rst_i | ~ena_i)
        begin
-	  sum_i <= 0;
-	  sum_q <= 0;
-	  total_i <= 0;
-	  total_q <= 0;
+	  sum_i <= #5 0;
+	  sum_q <= #5 0;
+	  total_i <= #5 0;
+	  total_q <= #5 0;
        end
-     else if (rx_strobe_o)
-       begin
-	  total_i <= sum_i + prod_i;
-	  total_q <= sum_q + prod_q;
-	  sum_i <= 0;
-	  sum_q <= 0;
-       end
-     else if (strobe_in)
-       begin
-	  sum_i = sum_i + prod_i;
-	  sum_q = sum_q + prod_q;
-       end
-   
+     else
+       if (sum_strobe_i)
+	 begin
+	    total_i <= #5 sum_i;
+	    total_q <= #5 sum_q;
+	    sum_i <= #5 prod_i;
+	    sum_q <= #5 prod_q;
+	 end
+       else
+	 begin
+	    sum_i <= #5 sum_i + prod_i;
+	    sum_q <= #5 sum_q + prod_q;
+	 end
+
+   wire [5:0]  offset = (5'd16-degree_i);
+   wire [31:0] scaled_i = total_i << offset;
+   wire [31:0] scaled_q = total_q << offset;
    assign rx_i_o = scaled_i[31:16];
    assign rx_q_o = scaled_q[31:16];