diff --git a/libraries/base/diag/src/vhdl/diag_pkg.vhd b/libraries/base/diag/src/vhdl/diag_pkg.vhd
index e0a6ac4f122bfa0f08410394890257945499fb23..7de4ec30950d9bdda57124649fc1aca59ec3a00c 100644
--- a/libraries/base/diag/src/vhdl/diag_pkg.vhd
+++ b/libraries/base/diag/src/vhdl/diag_pkg.vhd
@@ -162,7 +162,7 @@ PACKAGE diag_pkg IS
   -----------------------------------------------------------------------------
   -- Data buffer dev
   -----------------------------------------------------------------------------
-  CONSTANT c_diag_db_dev_reg_nof_dat : NATURAL := 8;
+  CONSTANT c_diag_db_dev_reg_nof_dat : NATURAL := 8;   -- Create headroom of 4 registers. 
   CONSTANT c_diag_db_dev_reg_adr_w   : NATURAL := ceil_log2(c_diag_db_dev_reg_nof_dat);
  
   -----------------------------------------------------------------------------