diff --git a/examples/sim/sim_config.py b/examples/sim/sim_config.py
index 1c5dfb5..17d54a1 100644
--- a/examples/sim/sim_config.py
+++ b/examples/sim/sim_config.py
@@ -2,32 +2,34 @@ from litedram.modules import MT41K128M16
 from litedram.phy import A7DDRPHY
 
 core_config = {
-    # cpu
-    "cpu": None,
+    # General ------------------------------------------------------------------
+    "cpu":        None,        # Type of CPU used for init/calib (vexriscv, lm32)
+    "speedgrade": -1,          # FPGA speedgrade
+    "memtype":    "DDR3",      # DRAM type
 
-    # modules / phy
-    "sdram_module": MT41K128M16,
-    "sdram_module_nb": 1,
-    "sdram_module_speedgrade": "800",
-    "sdram_rank_nb": 1,
-    "sdram_phy": A7DDRPHY,
+    # PHY ----------------------------------------------------------------------
+    "cmd_delay":       0,           # Command additional delay (in taps)
+    "cmd_latency":     0,           # Command additional latency
+    "sdram_module":    MT41K128M16, # SDRAM modules of the board or SO-DIMM
+    "sdram_module_nb": 2,           # Number of byte groups
+    "sdram_rank_nb":   1,           # Number of ranks
+    "sdram_phy":       A7DDRPHY,    # Type of FPGA PHY
 
-    # electrical
-    "rtt_nom": "60ohm",
-    "rtt_wr": "60ohm",
-    "ron": "34ohm",
+    # Electrical ---------------------------------------------------------------
+    "rtt_nom": "60ohm",  # Nominal termination
+    "rtt_wr":  "60ohm",  # Write termination
+    "ron":     "34ohm",  # Output driver impedance
 
-    # freqs
-    "input_clk_freq": 100e6,
-    "sys_clk_freq": 100e6,
-    "iodelay_clk_freq": 200e6,
+    # Frequency ----------------------------------------------------------------
+    "input_clk_freq":   100e6, # Input clock frequency
+    "sys_clk_freq":     100e6, # System clock frequency (DDR_clk = 4 x sys_clk)
+    "iodelay_clk_freq": 200e6, # IODELAYs reference clock frequency
 
-    # controller
-    "cmd_buffer_depth": 8,
-    "write_time": 16,
-    "read_time": 32,
+    # Core ---------------------------------------------------------------------
+    "cmd_buffer_depth": 16,    # Depth of the command buffer
 
-    # user_ports
-    "user_ports_nb": 2,
-    "user_ports_type": "native"
+    # User Ports ---------------------------------------------------------------
+    "user_ports_nb":       2,        # Number of user ports
+    "user_ports_type":     "native", # Type of ports (axi, native)
 }
+