processed review comments

applications/lofar2/libraries/sdp/src/vhdl/node_sdp_correlator.vhd

@@ -89,11 +89,19 @@ END node_sdp_correlator;
 
 ARCHITECTURE str OF node_sdp_correlator IS
    
-  CONSTANT c_nof_controllers : POSITIVE := 2;
-  CONSTANT c_block_size      : NATURAL  := c_sdp_N_crosslets_max * c_sdp_S_pn;
-  CONSTANT c_data_w          : NATURAL  := c_sdp_W_crosslet * c_nof_complex;
-  CONSTANT c_mux_fifo_size   : NATURAL  := 2**ceil_log2(g_P_sq * c_block_size); -- Large enough to store a block for each remote packet.
-  CONSTANT c_fifo_fill_size  : NATURAL  := 2**ceil_log2(3 * c_block_size); 
+  CONSTANT c_nof_controllers      : POSITIVE := 2;
+  CONSTANT c_block_size           : NATURAL  := c_sdp_N_crosslets_max * c_sdp_S_pn;
+  CONSTANT c_block_size_longwords : NATURAL  := ceil_div(c_block_size, 2); -- 32b -> 64b
+  CONSTANT c_data_w               : NATURAL  := c_sdp_W_crosslet * c_nof_complex;
+
+-- The size for 1 block is probably already enough as the number of blocks received
+-- on the remote input of the mux probably have enough gap time in between. Just
+-- to be sure to not run into issues in the future, the fifo size is increased to 
+-- buffer the maximum nof blocks per block period.
+  CONSTANT c_mux_fifo_size   : NATURAL  := 2**ceil_log2(g_P_sq * c_block_size_longwords); 
+-- c_fifo_fill_size should be at least 2 * c_block_size_longwords as dp_repack_data
+-- repacks from 64bit to 32bit. Chosing 3x to have some room.
+  CONSTANT c_fifo_fill_size  : NATURAL  := 2**ceil_log2(3 * c_block_size_longwords); 
 
 -- crosslet statistics offload
   SIGNAL ram_st_offload_copi           : t_mem_copi := c_mem_copi_rst;
@@ -246,7 +254,7 @@ BEGIN
     g_use_channel    => TRUE, 
     g_use_error      => TRUE, 
     g_use_sync       => TRUE, 
-    g_fifo_fill      => c_block_size,
+    g_fifo_fill      => c_block_size_longwords,
     g_fifo_size      => c_fifo_fill_size
   )
   PORT MAP (