Added Xilinx specific constraint attribute to preserve the ring oscillators. Fixed name of rosc instances.

1 files changed, 10 insertions, 7 deletions

diff --git a/src/rtl/rosc_entropy_core.v b/src/rtl/rosc_entropy_core.v
index 6fb48ec..eb9dd6e 100644
--- a/src/rtl/rosc_entropy_core.v
+++ b/src/rtl/rosc_entropy_core.v
@@ -104,6 +104,9 @@ module rosc_entropy_core(
   // Wires.
   //----------------------------------------------------------------
   reg           rosc_we;
+
+  // Ugly in-line Xilinx attribute to preserve the registers.
+  (* equivalent_register_removal = "no" *)
   wire [31 : 0] rosc_dout;
 
 
@@ -127,13 +130,13 @@ module rosc_entropy_core(
   generate
     for(i = 0 ; i < 32 ; i = i + 1)
       begin: oscillators
-        rosc #(.WIDTH(1)) osc_array(.clk(clk),
-                                    .we(rosc_we),
-                                    .reset_n(reset_n),
-                                    .opa(opa),
-                                    .opb(opb),
-                                    .dout(rosc_dout[i])
-                                   );
+        rosc #(.WIDTH(1)) rosc_array(.clk(clk),
+                                     .we(rosc_we),
+                                     .reset_n(reset_n),
+                                     .opa(opa),
+                                     .opb(opb),
+                                     .dout(rosc_dout[i])
+                                    );
       end
   endgenerate