diff --git a/libraries/io/ddr/src/vhdl/mms_io_ddr.vhd b/libraries/io/ddr/src/vhdl/mms_io_ddr.vhd
index 3a03de15ff6a3756470b714ddacdc0cfd82e2ff9..e8f1e68cdb11f47c3ad9c50c4400493dc9a02494 100644
--- a/libraries/io/ddr/src/vhdl/mms_io_ddr.vhd
+++ b/libraries/io/ddr/src/vhdl/mms_io_ddr.vhd
@@ -31,6 +31,7 @@ USE dp_lib.dp_stream_pkg.ALL;
 
 ENTITY mms_io_ddr IS
   GENERIC(
+    g_sim_model               : BOOLEAN := FALSE;
     g_technology              : NATURAL := c_tech_select_default;
     g_tech_ddr                : t_c_tech_ddr;
     g_cross_domain_dvr_ctlr   : BOOLEAN := TRUE;
@@ -83,7 +84,8 @@ ENTITY mms_io_ddr IS
     rd_fifo_usedw       : OUT   STD_LOGIC_VECTOR(ceil_log2(g_rd_fifo_depth * (func_tech_ddr_ctlr_data_w(g_tech_ddr)/g_rd_data_w) )-1 DOWNTO 0);    
     rd_sosi             : OUT   t_dp_sosi;
     rd_siso             : IN    t_dp_siso;
-                        
+    
+    -- DDR3 pass on termination control from master to slave controller
     term_ctrl_out       : OUT   t_tech_ddr3_phy_terminationcontrol;
     term_ctrl_in        : IN    t_tech_ddr3_phy_terminationcontrol := c_tech_ddr3_phy_terminationcontrol_rst;
                         
@@ -111,7 +113,7 @@ ARCHITECTURE str OF mms_io_ddr IS
 BEGIN
 
   -- Combine the reg map of io_ddr and io_ddr_reg
-  u_mm_mux : ENTITY common_lib.common_mem_mux
+  u_common_mem_mux : ENTITY common_lib.common_mem_mux
   GENERIC MAP (    
     g_nof_mosi    => 2,
     g_mult_addr_w => ceil_log2(8)
@@ -123,8 +125,9 @@ BEGIN
     miso_arr => reg_io_ddr_miso_arr
   );
 
-  u_ddr_mem_ctrl : ENTITY work.io_ddr
-  GENERIC MAP( 
+  u_io_ddr : ENTITY work.io_ddr
+  GENERIC MAP (
+    g_sim_model              => g_sim_model,
     g_technology             => g_technology,
     g_tech_ddr               => g_tech_ddr,
     g_cross_domain_dvr_ctlr  => FALSE, 
@@ -192,7 +195,8 @@ BEGIN
     phy4_ou       => phy4_ou
   );             
 
-  u_ddr_reg : ENTITY work.io_ddr_reg 
+  -- MM register map for DDR controller write and read access control via MM
+  u_io_ddr_reg : ENTITY work.io_ddr_reg 
   PORT MAP(
     -- Clocks and reset
     mm_rst          => mm_rst,