diff --git a/bin/p4def_to_simv.py b/bin/p4def_to_simv.py
index 8567b3b..b4043a2 100755
--- a/bin/p4def_to_simv.py
+++ b/bin/p4def_to_simv.py
@@ -444,8 +444,7 @@ def main():
                         format_char = "%d"
 
                     stream.write(f"\n    if (({param} < {minval}) || ({param} > {maxval})) begin\n")
-                    stream.write(f"       $display(\"{name} instance %m {param} set to incorrect value, {format_char}.  Values must be between {minval} and {maxval}.\", {param});\n")
-                    stream.write("    #1 $stop;\n")
+                    stream.write(f"       $fatal(1,\"{name} instance %m {param} set to incorrect value, {format_char}.  Values must be between {minval} and {maxval}.\", {param});\n")
                     stream.write("    end\n")
                     continue
 
@@ -469,8 +468,7 @@ def main():
                 stream.write(f"    case({param})\n")
                 stream.write(f"      {value_list_for_case}: begin end\n")
                 stream.write("      default: begin\n")
-                stream.write(f"        $display(\"\\nError: {name} instance %m has parameter {param} set to {format_char}.  Valid values are {value_list_for_msg}\\n\", {param});\n")
-                stream.write("        #1 $stop ;\n")
+                stream.write(f"        $fatal(1,\"\\nError: {name} instance %m has parameter {param} set to {format_char}.  Valid values are {value_list_for_msg}\\n\", {param});\n")
                 stream.write("      end\n")
                 stream.write("    endcase\n")
 
@@ -490,8 +488,7 @@ def main():
                         format_char = "%d"
 
                     stream.write(f"\n    if (({param} < {minval}) || ({param} > {maxval})) begin\n")
-                    stream.write(f"       $display(\"{name} instance %m {param} set to incorrect value, {format_char}.  Values must be between {minval} and {maxval}.\", {param});\n")
-                    stream.write("    #1 $stop;\n")
+                    stream.write(f"       $fatal(1,\"{name} instance %m {param} set to incorrect value, {format_char}.  Values must be between {minval} and {maxval}.\", {param});\n")
                     stream.write("    end\n")
                     continue
 
@@ -513,8 +510,7 @@ def main():
                 stream.write(f"\n    case({param})\n")
                 stream.write(f"      {value_list_for_case}: begin end\n")
                 stream.write("      default: begin\n")
-                stream.write(f"        $display(\"\\nError: {name} instance %m has parameter {param} set to %s.  Valid values are {value_list_for_msg}\\n\", {param});\n")
-                stream.write("        #1 $stop ;\n")
+                stream.write(f"        $fatal(1,\"\\nError: {name} instance %m has parameter {param} set to %s.  Valid values are {value_list_for_msg}\\n\", {param});\n")
                 stream.write("      end\n")
                 stream.write("    endcase\n")
 
diff --git a/models_customer/verilog/BOOT_CLOCK.v b/models_customer/verilog/BOOT_CLOCK.v
index de276cb..07fcf82 100644
--- a/models_customer/verilog/BOOT_CLOCK.v
+++ b/models_customer/verilog/BOOT_CLOCK.v
@@ -20,8 +20,7 @@ localparam HALF_PERIOD = PERIOD/2.0;
  initial begin
 
     if ((PERIOD < 16.0) || (PERIOD > 30.0)) begin
-       $display("BOOT_CLOCK instance %m PERIOD set to incorrect value, %f.  Values must be between 16.0 and 30.0.", PERIOD);
-    #1 $stop;
+       $fatal(1,"BOOT_CLOCK instance %m PERIOD set to incorrect value, %f.  Values must be between 16.0 and 30.0.", PERIOD);
     end
 
   end
diff --git a/models_customer/verilog/DSP19X2.v b/models_customer/verilog/DSP19X2.v
index 26018a3..044b655 100644
--- a/models_customer/verilog/DSP19X2.v
+++ b/models_customer/verilog/DSP19X2.v
@@ -381,15 +381,13 @@ module DSP19X2 #(
 	always @(ACC_FIR)
 		if (ACC_FIR > 21)
 		begin
-			$display("WARNING: DSP19x2 instance %m ACC_FIR input is %d which is greater than 21 which serves no function", ACC_FIR);
-			#1 $finish ;
+			$fatal(1,"WARNING: DSP19x2 instance %m ACC_FIR input is %d which is greater than 21 which serves no function", ACC_FIR);
 		end
 	// If SHIFT_RIGHT is greater than 31, result is invalid
 	always @(SHIFT_RIGHT)
 		if (SHIFT_RIGHT > 31)
 		begin
-			$display("WARNING: DSP19x2 instance %m SHIFT_RIGHT input is %d which is greater than 31 which serves no function", SHIFT_RIGHT);
-			#1 $finish ;
+			$fatal(1,"WARNING: DSP19x2 instance %m SHIFT_RIGHT input is %d which is greater than 31 which serves no function", SHIFT_RIGHT);
 		end
 	
 	always@(*) 
@@ -397,7 +395,7 @@ module DSP19X2 #(
 		case(DSP_MODE)
 			"MULTIPLY_ACCUMULATE": begin  
 				if(FEEDBACK>1)
-					$display("\nWARNING: DSP19x2 instance %m has parameter DSP_MODE set to %s and FEEDBACK set to %0d. Valid values of FEEDBACK for this mode are 0,1 \n", DSP_MODE,FEEDBACK);
+					$fatal(1,"\nWARNING: DSP19x2 instance %m has parameter DSP_MODE set to %s and FEEDBACK set to %0d. Valid values of FEEDBACK for this mode are 0,1 \n", DSP_MODE,FEEDBACK);
 			end
 		endcase
 		
@@ -409,24 +407,21 @@ module DSP19X2 #(
       "MULTIPLY_ADD_SUB" ,
       "MULTIPLY_ACCUMULATE": begin end
       default: begin
-        $display("\nError: DSP19X2 instance %m has parameter DSP_MODE set to %s.  Valid values are MULTIPLY, MULTIPLY_ADD_SUB, MULTIPLY_ACCUMULATE\n", DSP_MODE);
-        #1 $stop ;
+        $fatal(1,"\nError: DSP19X2 instance %m has parameter DSP_MODE set to %s.  Valid values are MULTIPLY, MULTIPLY_ADD_SUB, MULTIPLY_ACCUMULATE\n", DSP_MODE);
       end
     endcase
     case(OUTPUT_REG_EN)
       "TRUE" ,
       "FALSE": begin end
       default: begin
-        $display("\nError: DSP19X2 instance %m has parameter OUTPUT_REG_EN set to %s.  Valid values are TRUE, FALSE\n", OUTPUT_REG_EN);
-        #1 $stop ;
+        $fatal(1,"\nError: DSP19X2 instance %m has parameter OUTPUT_REG_EN set to %s.  Valid values are TRUE, FALSE\n", OUTPUT_REG_EN);
       end
     endcase
     case(INPUT_REG_EN)
       "TRUE" ,
       "FALSE": begin end
       default: begin
-        $display("\nError: DSP19X2 instance %m has parameter INPUT_REG_EN set to %s.  Valid values are TRUE, FALSE\n", INPUT_REG_EN);
-        #1 $stop ;
+        $fatal(1,"\nError: DSP19X2 instance %m has parameter INPUT_REG_EN set to %s.  Valid values are TRUE, FALSE\n", INPUT_REG_EN);
       end
     endcase
 
diff --git a/models_customer/verilog/DSP38.v b/models_customer/verilog/DSP38.v
index b6a65fc..b91519c 100644
--- a/models_customer/verilog/DSP38.v
+++ b/models_customer/verilog/DSP38.v
@@ -297,14 +297,14 @@ module DSP38 #(
 	// If ACC_FIR is greater than 43, result is invalid
 	always @(ACC_FIR)
 		if (ACC_FIR > 43)
-			$display("WARNING: DSP38 instance %m ACC_FIR input is %d which is greater than 43 which serves no function", ACC_FIR);
+			$fatal(1,"\nWARNING: DSP38 instance %m ACC_FIR input is %d which is greater than 43 which serves no function", ACC_FIR);
 
 	always@(*) 
 	begin
 		case(DSP_MODE)
 			"MULTIPLY_ACCUMULATE": begin  
 				if(FEEDBACK>1)
-					$display("\nWARNING: DSP38 instance %m has parameter DSP_MODE set to %s and FEEDBACK set to %0d. Valid values of FEEDBACK for this mode are 0,1 \n", DSP_MODE,FEEDBACK);
+					$fatal(1,"\nWARNING: DSP38 instance %m has parameter DSP_MODE set to %s and FEEDBACK set to %0d. Valid values of FEEDBACK for this mode are 0,1 \n", DSP_MODE,FEEDBACK);
 			end
 		endcase
 		
@@ -316,24 +316,21 @@ module DSP38 #(
       "MULTIPLY_ADD_SUB" ,
       "MULTIPLY_ACCUMULATE": begin end
       default: begin
-        $display("\nError: DSP38 instance %m has parameter DSP_MODE set to %s.  Valid values are MULTIPLY, MULTIPLY_ADD_SUB, MULTIPLY_ACCUMULATE\n", DSP_MODE);
-        #1 $stop ;
+        $fatal(1,"\nError: DSP38 instance %m has parameter DSP_MODE set to %s.  Valid values are MULTIPLY, MULTIPLY_ADD_SUB, MULTIPLY_ACCUMULATE\n", DSP_MODE);
       end
     endcase
     case(OUTPUT_REG_EN)
       "TRUE" ,
       "FALSE": begin end
       default: begin
-        $display("\nError: DSP38 instance %m has parameter OUTPUT_REG_EN set to %s.  Valid values are TRUE, FALSE\n", OUTPUT_REG_EN);
-        #1 $stop ;
+        $fatal(1,"\nError: DSP38 instance %m has parameter OUTPUT_REG_EN set to %s.  Valid values are TRUE, FALSE\n", OUTPUT_REG_EN);
       end
     endcase
     case(INPUT_REG_EN)
       "TRUE" ,
       "FALSE": begin end
       default: begin
-        $display("\nError: DSP38 instance %m has parameter INPUT_REG_EN set to %s.  Valid values are TRUE, FALSE\n", INPUT_REG_EN);
-        #1 $stop ;
+        $fatal(1,"\nError: DSP38 instance %m has parameter INPUT_REG_EN set to %s.  Valid values are TRUE, FALSE\n", INPUT_REG_EN);
       end
     endcase
 
diff --git a/models_customer/verilog/FIFO18KX2.v b/models_customer/verilog/FIFO18KX2.v
index 62b8e89..8109b6d 100644
--- a/models_customer/verilog/FIFO18KX2.v
+++ b/models_customer/verilog/FIFO18KX2.v
@@ -337,48 +337,42 @@ tdp_ram18kx2_inst
       9 ,
       18: begin end
       default: begin
-        $display("\nError: FIFO18KX2 instance %m has parameter DATA_WRITE_WIDTH1 set to %d.  Valid values are 9, 18\n", DATA_WRITE_WIDTH1);
-        #1 $stop ;
+        $fatal(1,"\nError: FIFO18KX2 instance %m has parameter DATA_WRITE_WIDTH1 set to %d.  Valid values are 9, 18\n", DATA_WRITE_WIDTH1);
       end
     endcase
     case(DATA_READ_WIDTH1)
       9 ,
       18: begin end
       default: begin
-        $display("\nError: FIFO18KX2 instance %m has parameter DATA_READ_WIDTH1 set to %d.  Valid values are 9, 18\n", DATA_READ_WIDTH1);
-        #1 $stop ;
+        $fatal(1,"\nError: FIFO18KX2 instance %m has parameter DATA_READ_WIDTH1 set to %d.  Valid values are 9, 18\n", DATA_READ_WIDTH1);
       end
     endcase
     case(FIFO_TYPE1)
       "SYNCHRONOUS" ,
       "ASYNCHRONOUS": begin end
       default: begin
-        $display("\nError: FIFO18KX2 instance %m has parameter FIFO_TYPE1 set to %s.  Valid values are SYNCHRONOUS, ASYNCHRONOUS\n", FIFO_TYPE1);
-        #1 $stop ;
+        $fatal(1,"\nError: FIFO18KX2 instance %m has parameter FIFO_TYPE1 set to %s.  Valid values are SYNCHRONOUS, ASYNCHRONOUS\n", FIFO_TYPE1);
       end
     endcase
     case(DATA_WRITE_WIDTH2)
       9 ,
       18: begin end
       default: begin
-        $display("\nError: FIFO18KX2 instance %m has parameter DATA_WRITE_WIDTH2 set to %d.  Valid values are 9, 18\n", DATA_WRITE_WIDTH2);
-        #1 $stop ;
+        $fatal(1,"\nError: FIFO18KX2 instance %m has parameter DATA_WRITE_WIDTH2 set to %d.  Valid values are 9, 18\n", DATA_WRITE_WIDTH2);
       end
     endcase
     case(DATA_READ_WIDTH2)
       9 ,
       18: begin end
       default: begin
-        $display("\nError: FIFO18KX2 instance %m has parameter DATA_READ_WIDTH2 set to %d.  Valid values are 9, 18\n", DATA_READ_WIDTH2);
-        #1 $stop ;
+        $fatal(1,"\nError: FIFO18KX2 instance %m has parameter DATA_READ_WIDTH2 set to %d.  Valid values are 9, 18\n", DATA_READ_WIDTH2);
       end
     endcase
     case(FIFO_TYPE2)
       "SYNCHRONOUS" ,
       "ASYNCHRONOUS": begin end
       default: begin
-        $display("\nError: FIFO18KX2 instance %m has parameter FIFO_TYPE2 set to %s.  Valid values are SYNCHRONOUS, ASYNCHRONOUS\n", FIFO_TYPE2);
-        #1 $stop ;
+        $fatal(1,"\nError: FIFO18KX2 instance %m has parameter FIFO_TYPE2 set to %s.  Valid values are SYNCHRONOUS, ASYNCHRONOUS\n", FIFO_TYPE2);
       end
     endcase
 
diff --git a/models_customer/verilog/FIFO36K.v b/models_customer/verilog/FIFO36K.v
index 43c0643..c23d16c 100644
--- a/models_customer/verilog/FIFO36K.v
+++ b/models_customer/verilog/FIFO36K.v
@@ -202,8 +202,7 @@ module FIFO36K #(
       18 ,
       36: begin end
       default: begin
-        $display("\nError: FIFO36K instance %m has parameter DATA_WRITE_WIDTH set to %d.  Valid values are 9, 18, 36\n", DATA_WRITE_WIDTH);
-        #1 $stop ;
+        $fatal(1,"\nError: FIFO36K instance %m has parameter DATA_WRITE_WIDTH set to %d.  Valid values are 9, 18, 36\n", DATA_WRITE_WIDTH);
       end
     endcase
     case(DATA_READ_WIDTH)
@@ -211,16 +210,14 @@ module FIFO36K #(
       18 ,
       36: begin end
       default: begin
-        $display("\nError: FIFO36K instance %m has parameter DATA_READ_WIDTH set to %d.  Valid values are 9, 18, 36\n", DATA_READ_WIDTH);
-        #1 $stop ;
+        $fatal(1,"\nError: FIFO36K instance %m has parameter DATA_READ_WIDTH set to %d.  Valid values are 9, 18, 36\n", DATA_READ_WIDTH);
       end
     endcase
     case(FIFO_TYPE)
       "SYNCHRONOUS" ,
       "ASYNCHRONOUS": begin end
       default: begin
-        $display("\nError: FIFO36K instance %m has parameter FIFO_TYPE set to %s.  Valid values are SYNCHRONOUS, ASYNCHRONOUS\n", FIFO_TYPE);
-        #1 $stop ;
+        $fatal(1,"\nError: FIFO36K instance %m has parameter FIFO_TYPE set to %s.  Valid values are SYNCHRONOUS, ASYNCHRONOUS\n", FIFO_TYPE);
       end
     endcase
 
diff --git a/models_customer/verilog/I_BUF.v b/models_customer/verilog/I_BUF.v
index 31eb06c..77781dc 100644
--- a/models_customer/verilog/I_BUF.v
+++ b/models_customer/verilog/I_BUF.v
@@ -31,8 +31,7 @@ module I_BUF #(
       "PULLUP" ,
       "PULLDOWN": begin end
       default: begin
-        $display("\nError: I_BUF instance %m has parameter WEAK_KEEPER set to %s.  Valid values are NONE, PULLUP, PULLDOWN\n", WEAK_KEEPER);
-        #1 $stop ;
+        $fatal(1,"\nError: I_BUF instance %m has parameter WEAK_KEEPER set to %s.  Valid values are NONE, PULLUP, PULLDOWN\n", WEAK_KEEPER);
       end
     endcase
 
diff --git a/models_customer/verilog/I_BUF_DS.v b/models_customer/verilog/I_BUF_DS.v
index 990598a..8041c7c 100644
--- a/models_customer/verilog/I_BUF_DS.v
+++ b/models_customer/verilog/I_BUF_DS.v
@@ -44,8 +44,7 @@ module I_BUF_DS #(
       "PULLUP" ,
       "PULLDOWN": begin end
       default: begin
-        $display("\nError: I_BUF_DS instance %m has parameter WEAK_KEEPER set to %s.  Valid values are NONE, PULLUP, PULLDOWN\n", WEAK_KEEPER);
-        #1 $stop ;
+        $fatal(1,"\nError: I_BUF_DS instance %m has parameter WEAK_KEEPER set to %s.  Valid values are NONE, PULLUP, PULLDOWN\n", WEAK_KEEPER);
       end
     endcase
     case(IOSTANDARD)
@@ -66,16 +65,14 @@ module I_BUF_DS #(
       "SSTL_18_HP_DIFF" ,
       "SSTL_18_HR_DIFF": begin end
       default: begin
-        $display("\nError: I_BUF_DS instance %m has parameter IOSTANDARD set to %s.  Valid values are DEFAULT, BLVDS_DIFF, LVDS_HP_DIFF, LVDS_HR_DIFF, LVPECL_25_DIFF, LVPECL_33_DIFF, HSTL_12_DIFF, HSTL_15_DIFF, HSUL_12_DIFF, MIPI_DIFF, POD_12_DIFF, RSDS_DIFF, SLVS_DIFF, SSTL_15_DIFF, SSTL_18_HP_DIFF, SSTL_18_HR_DIFF\n", IOSTANDARD);
-        #1 $stop ;
+        $fatal(1,"\nError: I_BUF_DS instance %m has parameter IOSTANDARD set to %s.  Valid values are DEFAULT, BLVDS_DIFF, LVDS_HP_DIFF, LVDS_HR_DIFF, LVPECL_25_DIFF, LVPECL_33_DIFF, HSTL_12_DIFF, HSTL_15_DIFF, HSUL_12_DIFF, MIPI_DIFF, POD_12_DIFF, RSDS_DIFF, SLVS_DIFF, SSTL_15_DIFF, SSTL_18_HP_DIFF, SSTL_18_HR_DIFF\n", IOSTANDARD);
       end
     endcase
     case(DIFFERENTIAL_TERMINATION)
       "TRUE" ,
       "FALSE": begin end
       default: begin
-        $display("\nError: I_BUF_DS instance %m has parameter DIFFERENTIAL_TERMINATION set to %s.  Valid values are TRUE, FALSE\n", DIFFERENTIAL_TERMINATION);
-        #1 $stop ;
+        $fatal(1,"\nError: I_BUF_DS instance %m has parameter DIFFERENTIAL_TERMINATION set to %s.  Valid values are TRUE, FALSE\n", DIFFERENTIAL_TERMINATION);
       end
     endcase
 
diff --git a/models_customer/verilog/I_DELAY.v b/models_customer/verilog/I_DELAY.v
index b9690b2..bd8f6b5 100644
--- a/models_customer/verilog/I_DELAY.v
+++ b/models_customer/verilog/I_DELAY.v
@@ -59,8 +59,7 @@ assign #(30.0ps + (21.56ps*dly_tap_val)) O = I;			// Adjusted Delay for TT corne
  initial begin
 
     if ((DELAY < 0) || (DELAY > 63)) begin
-       $display("I_DELAY instance %m DELAY set to incorrect value, %d.  Values must be between 0 and 63.", DELAY);
-    #1 $stop;
+       $fatal(1,"I_DELAY instance %m DELAY set to incorrect value, %d.  Values must be between 0 and 63.", DELAY);
     end
 
   end
diff --git a/models_customer/verilog/I_FAB.v b/models_customer/verilog/I_FAB.v
new file mode 100644
index 0000000..a69b17e
--- /dev/null
+++ b/models_customer/verilog/I_FAB.v
@@ -0,0 +1,19 @@
+`timescale 1ns/1ps
+`celldefine
+//
+// I_FAB simulation model
+// Marker Buffer for periphery to fabric transition
+//
+// Copyright (c) 2023 Rapid Silicon, Inc.  All rights reserved.
+//
+
+module I_FAB (
+  input I, // Input
+  output O // Output
+);
+
+assign O = I ;
+
+
+endmodule
+`endcelldefine
diff --git a/models_customer/verilog/I_SERDES.v b/models_customer/verilog/I_SERDES.v
index a9078dd..76061d7 100644
--- a/models_customer/verilog/I_SERDES.v
+++ b/models_customer/verilog/I_SERDES.v
@@ -758,22 +758,19 @@ assign DATA_VALID=!des_fifo_empty;
       "SDR" ,
       "DDR": begin end
       default: begin
-        $display("\nError: I_SERDES instance %m has parameter DATA_RATE set to %s.  Valid values are SDR, DDR\n", DATA_RATE);
-        #1 $stop ;
+        $fatal(1,"\nError: I_SERDES instance %m has parameter DATA_RATE set to %s.  Valid values are SDR, DDR\n", DATA_RATE);
       end
     endcase
 
     if ((WIDTH < 3) || (WIDTH > 10)) begin
-       $display("I_SERDES instance %m WIDTH set to incorrect value, %d.  Values must be between 3 and 10.", WIDTH);
-    #1 $stop;
+       $fatal(1,"I_SERDES instance %m WIDTH set to incorrect value, %d.  Values must be between 3 and 10.", WIDTH);
     end
     case(DPA_MODE)
       "NONE" ,
       "DPA" ,
       "CDR": begin end
       default: begin
-        $display("\nError: I_SERDES instance %m has parameter DPA_MODE set to %s.  Valid values are NONE, DPA, CDR\n", DPA_MODE);
-        #1 $stop ;
+        $fatal(1,"\nError: I_SERDES instance %m has parameter DPA_MODE set to %s.  Valid values are NONE, DPA, CDR\n", DPA_MODE);
       end
     endcase
 
diff --git a/models_customer/verilog/O_BUFT.v b/models_customer/verilog/O_BUFT.v
index 55e3599..d0f48e5 100644
--- a/models_customer/verilog/O_BUFT.v
+++ b/models_customer/verilog/O_BUFT.v
@@ -31,8 +31,7 @@ module O_BUFT #(
       "PULLUP" ,
       "PULLDOWN": begin end
       default: begin
-        $display("\nError: O_BUFT instance %m has parameter WEAK_KEEPER set to %s.  Valid values are NONE, PULLUP, PULLDOWN\n", WEAK_KEEPER);
-        #1 $stop ;
+        $fatal(1,"\nError: O_BUFT instance %m has parameter WEAK_KEEPER set to %s.  Valid values are NONE, PULLUP, PULLDOWN\n", WEAK_KEEPER);
       end
     endcase
 
diff --git a/models_customer/verilog/O_BUFT_DS.v b/models_customer/verilog/O_BUFT_DS.v
index 7fcc3a7..e2a9885 100644
--- a/models_customer/verilog/O_BUFT_DS.v
+++ b/models_customer/verilog/O_BUFT_DS.v
@@ -35,8 +35,7 @@ module O_BUFT_DS #(
       "PULLUP" ,
       "PULLDOWN": begin end
       default: begin
-        $display("\nError: O_BUFT_DS instance %m has parameter WEAK_KEEPER set to %s.  Valid values are NONE, PULLUP, PULLDOWN\n", WEAK_KEEPER);
-        #1 $stop ;
+        $fatal(1,"\nError: O_BUFT_DS instance %m has parameter WEAK_KEEPER set to %s.  Valid values are NONE, PULLUP, PULLDOWN\n", WEAK_KEEPER);
       end
     endcase
 
diff --git a/models_customer/verilog/O_DELAY.v b/models_customer/verilog/O_DELAY.v
index 4bd98ae..470438d 100644
--- a/models_customer/verilog/O_DELAY.v
+++ b/models_customer/verilog/O_DELAY.v
@@ -59,8 +59,7 @@ assign #(30.0ps + (21.56ps*dly_tap_val)) O = I;				// Adjusted Delay for TT corn
  initial begin
 
     if ((DELAY < 0) || (DELAY > 63)) begin
-       $display("O_DELAY instance %m DELAY set to incorrect value, %d.  Values must be between 0 and 63.", DELAY);
-    #1 $stop;
+       $fatal(1,"O_DELAY instance %m DELAY set to incorrect value, %d.  Values must be between 0 and 63.", DELAY);
     end
 
   end
diff --git a/models_customer/verilog/O_FAB.v b/models_customer/verilog/O_FAB.v
new file mode 100644
index 0000000..956a0a2
--- /dev/null
+++ b/models_customer/verilog/O_FAB.v
@@ -0,0 +1,18 @@
+`timescale 1ns/1ps
+`celldefine
+//
+// O_FAB simulation model
+// Marker Buffer for fabric to periphery transition
+//
+// Copyright (c) 2023 Rapid Silicon, Inc.  All rights reserved.
+//
+
+module O_FAB (
+  input I, // Input
+  output O // Output
+);
+
+assign O = I ;
+
+endmodule
+`endcelldefine
diff --git a/models_customer/verilog/O_SERDES.v b/models_customer/verilog/O_SERDES.v
index b4996c9..482b693 100644
--- a/models_customer/verilog/O_SERDES.v
+++ b/models_customer/verilog/O_SERDES.v
@@ -244,14 +244,12 @@ module O_SERDES #(
       "SDR" ,
       "DDR": begin end
       default: begin
-        $display("\nError: O_SERDES instance %m has parameter DATA_RATE set to %s.  Valid values are SDR, DDR\n", DATA_RATE);
-        #1 $stop ;
+        $fatal(1,"\nError: O_SERDES instance %m has parameter DATA_RATE set to %s.  Valid values are SDR, DDR\n", DATA_RATE);
       end
     endcase
 
     if ((WIDTH < 3) || (WIDTH > 10)) begin
-       $display("O_SERDES instance %m WIDTH set to incorrect value, %d.  Values must be between 3 and 10.", WIDTH);
-    #1 $stop;
+       $fatal(1,"O_SERDES instance %m WIDTH set to incorrect value, %d.  Values must be between 3 and 10.", WIDTH);
     end
 
   end
diff --git a/models_customer/verilog/O_SERDES_CLK.v b/models_customer/verilog/O_SERDES_CLK.v
index cde9760..674d02f 100644
--- a/models_customer/verilog/O_SERDES_CLK.v
+++ b/models_customer/verilog/O_SERDES_CLK.v
@@ -53,8 +53,7 @@ module O_SERDES_CLK #(
       "SDR" ,
       "DDR": begin end
       default: begin
-        $display("\nError: O_SERDES_CLK instance %m has parameter DATA_RATE set to %s.  Valid values are SDR, DDR\n", DATA_RATE);
-        #1 $stop ;
+        $fatal(1,"\nError: O_SERDES_CLK instance %m has parameter DATA_RATE set to %s.  Valid values are SDR, DDR\n", DATA_RATE);
       end
     endcase
     case(CLOCK_PHASE)
@@ -63,8 +62,7 @@ module O_SERDES_CLK #(
       180 ,
       270: begin end
       default: begin
-        $display("\nError: O_SERDES_CLK instance %m has parameter CLOCK_PHASE set to %d.  Valid values are 0, 90, 180, 270\n", CLOCK_PHASE);
-        #1 $stop ;
+        $fatal(1,"\nError: O_SERDES_CLK instance %m has parameter CLOCK_PHASE set to %d.  Valid values are 0, 90, 180, 270\n", CLOCK_PHASE);
       end
     endcase
 
diff --git a/models_customer/verilog/PLL.v b/models_customer/verilog/PLL.v
index d3af947..1efcd89 100644
--- a/models_customer/verilog/PLL.v
+++ b/models_customer/verilog/PLL.v
@@ -160,12 +160,10 @@ localparam      FAST_LOCK      = 0; // Reduce lock time
 	always @ (posedge CLK_IN) begin
 		if(pllstart_ff2)begin
 			if (ref_period<VCO_MIN_PERIOD) begin
-				$display("\nError at time %t: PLL instance %m REF clock period %0d fs violates minimum period.\nMust be greater than %0d fs.\n", $realtime, ref_period, VCO_MIN_PERIOD);
-				$stop;
+				$fatal(1,"\nError at time %t: PLL instance %m REF clock period %0d fs violates minimum period.\nMust be greater than %0d fs.\n", $realtime, ref_period, VCO_MIN_PERIOD);
 			end
 			else if (ref_period>VCO_MAX_PERIOD) begin
-				$display("\nError at time %t: PLL instance %m REF clock period %0d fs violates maximum period.\nMust be less than %0d fs.\n", $realtime, ref_period, VCO_MAX_PERIOD);
-				$stop;
+				$fatal(1,"\nError at time %t: PLL instance %m REF clock period %0d fs violates maximum period.\nMust be less than %0d fs.\n", $realtime, ref_period, VCO_MAX_PERIOD);
 			end
 		end
 	end
@@ -182,12 +180,10 @@ localparam      FAST_LOCK      = 0; // Reduce lock time
 	always @ (posedge FAST_CLK) begin
 		if(vcostart_ff) begin
 			if (vco_period<VCO_MIN_PERIOD) begin
-				$display("\nError at time %t: PLL instance %m VCO clock period %0d fs violates minimum period.\nMust be greater than %0d fs.\nTry increasing PLL_DIV or decreasing PLL_MULT values.\n", $realtime, vco_period, VCO_MIN_PERIOD);
-				$stop;
+				$fatal(1,"\nError at time %t: PLL instance %m VCO clock period %0d fs violates minimum period.\nMust be greater than %0d fs.\nTry increasing PLL_DIV or decreasing PLL_MULT values.\n", $realtime, vco_period, VCO_MIN_PERIOD);
 			end
 			else if (vco_period>VCO_MAX_PERIOD) begin
-				$display("\nError at time %t: PLL instance %m VCO clock period %0d fs violates maximum period.\nMust be less than %0d fs.\nTry increasing PLL_MULT or decreasing PLL_DIV values.\n", $realtime, vco_period, VCO_MAX_PERIOD);
-				$stop;
+				$fatal(1,"\nError at time %t: PLL instance %m VCO clock period %0d fs violates maximum period.\nMust be less than %0d fs.\nTry increasing PLL_MULT or decreasing PLL_DIV values.\n", $realtime, vco_period, VCO_MAX_PERIOD);
 			end
 		end
 	end
@@ -198,19 +194,16 @@ localparam      FAST_LOCK      = 0; // Reduce lock time
 	always @ (posedge CLK_IN, posedge PLL_EN) begin
 		if(PLL_EN)begin
 			if(PLL_POST_DIV0==0)begin
-				$display("Error at time %t: \n \t PLL instance %m, PLL_POST_DIV0 is equal to zero.\n \t Must be greater than 0", $realtime);
-            $stop;
+				$fatal(1,"Error at time %t: \n \t PLL instance %m, PLL_POST_DIV0 is equal to zero.\n \t Must be greater than 0", $realtime);
 			end
 
 			else if(PLL_POST_DIV1==0)begin
-				$display("Error at time %t: \n \t PLL instance %m, PLL_POST_DIV1 is equal to zero.\n \t Must be greater than 0", $realtime);
-				$stop;
+				$fatal(1,"Error at time %t: \n \t PLL instance %m, PLL_POST_DIV1 is equal to zero.\n \t Must be greater than 0", $realtime);
 			end
 
 
 			else if(PLL_POST_DIV1>PLL_POST_DIV0) begin
-				$display("Error at time %t: PLL_POST_DIV1 > PLL_POST_DIV0\n", $realtime);
-				$stop;
+				$fatal(1,"Error at time %t: PLL_POST_DIV1 > PLL_POST_DIV0\n", $realtime);
 			end
 		end
 	end
@@ -219,33 +212,28 @@ localparam      FAST_LOCK      = 0; // Reduce lock time
     case(DEV_FAMILY)
       "VIRGO": begin end
       default: begin
-        $display("\nError: PLL instance %m has parameter DEV_FAMILY set to %s.  Valid values are VIRGO\n", DEV_FAMILY);
-        #1 $stop ;
+        $fatal(1,"\nError: PLL instance %m has parameter DEV_FAMILY set to %s.  Valid values are VIRGO\n", DEV_FAMILY);
       end
     endcase
     case(DIVIDE_CLK_IN_BY_2)
       "TRUE" ,
       "FALSE": begin end
       default: begin
-        $display("\nError: PLL instance %m has parameter DIVIDE_CLK_IN_BY_2 set to %s.  Valid values are TRUE, FALSE\n", DIVIDE_CLK_IN_BY_2);
-        #1 $stop ;
+        $fatal(1,"\nError: PLL instance %m has parameter DIVIDE_CLK_IN_BY_2 set to %s.  Valid values are TRUE, FALSE\n", DIVIDE_CLK_IN_BY_2);
       end
     endcase
 
     if ((PLL_MULT < 16) || (PLL_MULT > 640)) begin
-       $display("PLL instance %m PLL_MULT set to incorrect value, %d.  Values must be between 16 and 640.", PLL_MULT);
-    #1 $stop;
+       $fatal(1,"PLL instance %m PLL_MULT set to incorrect value, %d.  Values must be between 16 and 640.", PLL_MULT);
     end
 
     if ((PLL_DIV < 1) || (PLL_DIV > 63)) begin
-       $display("PLL instance %m PLL_DIV set to incorrect value, %d.  Values must be between 1 and 63.", PLL_DIV);
-    #1 $stop;
+       $fatal(1,"PLL instance %m PLL_DIV set to incorrect value, %d.  Values must be between 1 and 63.", PLL_DIV);
     end
     case(PLL_MULT_FRAC)
       0: begin end
       default: begin
-        $display("\nError: PLL instance %m has parameter PLL_MULT_FRAC set to %d.  Valid values are 0\n", PLL_MULT_FRAC);
-        #1 $stop ;
+        $fatal(1,"\nError: PLL instance %m has parameter PLL_MULT_FRAC set to %d.  Valid values are 0\n", PLL_MULT_FRAC);
       end
     endcase
     case(PLL_POST_DIV)
@@ -278,8 +266,7 @@ localparam      FAST_LOCK      = 0; // Reduce lock time
       103 ,
       119: begin end
       default: begin
-        $display("\nError: PLL instance %m has parameter PLL_POST_DIV set to %d.  Valid values are 17, 18, 19, 20, 21, 22, 23, 34, 35, 36, 37, 38, 39, 51, 52, 53, 54, 55, 68, 69, 70, 71, 85, 86, 87, 102, 103, 119\n", PLL_POST_DIV);
-        #1 $stop ;
+        $fatal(1,"\nError: PLL instance %m has parameter PLL_POST_DIV set to %d.  Valid values are 17, 18, 19, 20, 21, 22, 23, 34, 35, 36, 37, 38, 39, 51, 52, 53, 54, 55, 68, 69, 70, 71, 85, 86, 87, 102, 103, 119\n", PLL_POST_DIV);
       end
     endcase
 
diff --git a/models_customer/verilog/SOC_FPGA_TEMPERATURE.v b/models_customer/verilog/SOC_FPGA_TEMPERATURE.v
index 23ea46a..67727a0 100644
--- a/models_customer/verilog/SOC_FPGA_TEMPERATURE.v
+++ b/models_customer/verilog/SOC_FPGA_TEMPERATURE.v
@@ -71,8 +71,7 @@ module SOC_FPGA_TEMPERATURE #(
  initial begin
 
     if ((INITIAL_TEMPERATURE < 0) || (INITIAL_TEMPERATURE > 125)) begin
-       $display("SOC_FPGA_TEMPERATURE instance %m INITIAL_TEMPERATURE set to incorrect value, %d.  Values must be between 0 and 125.", INITIAL_TEMPERATURE);
-    #1 $stop;
+       $fatal(1,"SOC_FPGA_TEMPERATURE instance %m INITIAL_TEMPERATURE set to incorrect value, %d.  Values must be between 0 and 125.", INITIAL_TEMPERATURE);
     end
 
   end
diff --git a/models_customer/verilog/TDP_RAM18KX2.v b/models_customer/verilog/TDP_RAM18KX2.v
index d8e96a7..afd8d7a 100644
--- a/models_customer/verilog/TDP_RAM18KX2.v
+++ b/models_customer/verilog/TDP_RAM18KX2.v
@@ -844,8 +844,7 @@ module TDP_RAM18KX2 #(
       9 ,
       18: begin end
       default: begin
-        $display("\nError: TDP_RAM18KX2 instance %m has parameter WRITE_WIDTH_A1 set to %d.  Valid values are 1, 2, 4, 9, 18\n", WRITE_WIDTH_A1);
-        #1 $stop ;
+        $fatal(1,"\nError: TDP_RAM18KX2 instance %m has parameter WRITE_WIDTH_A1 set to %d.  Valid values are 1, 2, 4, 9, 18\n", WRITE_WIDTH_A1);
       end
     endcase
     case(WRITE_WIDTH_B1)
@@ -855,8 +854,7 @@ module TDP_RAM18KX2 #(
       9 ,
       18: begin end
       default: begin
-        $display("\nError: TDP_RAM18KX2 instance %m has parameter WRITE_WIDTH_B1 set to %d.  Valid values are 1, 2, 4, 9, 18\n", WRITE_WIDTH_B1);
-        #1 $stop ;
+        $fatal(1,"\nError: TDP_RAM18KX2 instance %m has parameter WRITE_WIDTH_B1 set to %d.  Valid values are 1, 2, 4, 9, 18\n", WRITE_WIDTH_B1);
       end
     endcase
     case(READ_WIDTH_A1)
@@ -866,8 +864,7 @@ module TDP_RAM18KX2 #(
       9 ,
       18: begin end
       default: begin
-        $display("\nError: TDP_RAM18KX2 instance %m has parameter READ_WIDTH_A1 set to %d.  Valid values are 1, 2, 4, 9, 18\n", READ_WIDTH_A1);
-        #1 $stop ;
+        $fatal(1,"\nError: TDP_RAM18KX2 instance %m has parameter READ_WIDTH_A1 set to %d.  Valid values are 1, 2, 4, 9, 18\n", READ_WIDTH_A1);
       end
     endcase
     case(READ_WIDTH_B1)
@@ -877,8 +874,7 @@ module TDP_RAM18KX2 #(
       9 ,
       18: begin end
       default: begin
-        $display("\nError: TDP_RAM18KX2 instance %m has parameter READ_WIDTH_B1 set to %d.  Valid values are 1, 2, 4, 9, 18\n", READ_WIDTH_B1);
-        #1 $stop ;
+        $fatal(1,"\nError: TDP_RAM18KX2 instance %m has parameter READ_WIDTH_B1 set to %d.  Valid values are 1, 2, 4, 9, 18\n", READ_WIDTH_B1);
       end
     endcase
     case(WRITE_WIDTH_A2)
@@ -888,8 +884,7 @@ module TDP_RAM18KX2 #(
       9 ,
       18: begin end
       default: begin
-        $display("\nError: TDP_RAM18KX2 instance %m has parameter WRITE_WIDTH_A2 set to %d.  Valid values are 1, 2, 4, 9, 18\n", WRITE_WIDTH_A2);
-        #1 $stop ;
+        $fatal(1,"\nError: TDP_RAM18KX2 instance %m has parameter WRITE_WIDTH_A2 set to %d.  Valid values are 1, 2, 4, 9, 18\n", WRITE_WIDTH_A2);
       end
     endcase
     case(WRITE_WIDTH_B2)
@@ -899,8 +894,7 @@ module TDP_RAM18KX2 #(
       9 ,
       18: begin end
       default: begin
-        $display("\nError: TDP_RAM18KX2 instance %m has parameter WRITE_WIDTH_B2 set to %d.  Valid values are 1, 2, 4, 9, 18\n", WRITE_WIDTH_B2);
-        #1 $stop ;
+        $fatal(1,"\nError: TDP_RAM18KX2 instance %m has parameter WRITE_WIDTH_B2 set to %d.  Valid values are 1, 2, 4, 9, 18\n", WRITE_WIDTH_B2);
       end
     endcase
     case(READ_WIDTH_A2)
@@ -910,8 +904,7 @@ module TDP_RAM18KX2 #(
       9 ,
       18: begin end
       default: begin
-        $display("\nError: TDP_RAM18KX2 instance %m has parameter READ_WIDTH_A2 set to %d.  Valid values are 1, 2, 4, 9, 18\n", READ_WIDTH_A2);
-        #1 $stop ;
+        $fatal(1,"\nError: TDP_RAM18KX2 instance %m has parameter READ_WIDTH_A2 set to %d.  Valid values are 1, 2, 4, 9, 18\n", READ_WIDTH_A2);
       end
     endcase
     case(READ_WIDTH_B2)
@@ -921,8 +914,7 @@ module TDP_RAM18KX2 #(
       9 ,
       18: begin end
       default: begin
-        $display("\nError: TDP_RAM18KX2 instance %m has parameter READ_WIDTH_B2 set to %d.  Valid values are 1, 2, 4, 9, 18\n", READ_WIDTH_B2);
-        #1 $stop ;
+        $fatal(1,"\nError: TDP_RAM18KX2 instance %m has parameter READ_WIDTH_B2 set to %d.  Valid values are 1, 2, 4, 9, 18\n", READ_WIDTH_B2);
       end
     endcase
 
diff --git a/models_customer/verilog/TDP_RAM36K.v b/models_customer/verilog/TDP_RAM36K.v
index 78c88e9..12bda78 100644
--- a/models_customer/verilog/TDP_RAM36K.v
+++ b/models_customer/verilog/TDP_RAM36K.v
@@ -488,8 +488,7 @@ module TDP_RAM36K #(
       18 ,
       36: begin end
       default: begin
-        $display("\nError: TDP_RAM36K instance %m has parameter WRITE_WIDTH_A set to %d.  Valid values are 1, 2, 4, 9, 18, 36\n", WRITE_WIDTH_A);
-        #1 $stop ;
+        $fatal(1,"\nError: TDP_RAM36K instance %m has parameter WRITE_WIDTH_A set to %d.  Valid values are 1, 2, 4, 9, 18, 36\n", WRITE_WIDTH_A);
       end
     endcase
     case(READ_WIDTH_A)
@@ -500,8 +499,7 @@ module TDP_RAM36K #(
       18 ,
       36: begin end
       default: begin
-        $display("\nError: TDP_RAM36K instance %m has parameter READ_WIDTH_A set to %d.  Valid values are 1, 2, 4, 9, 18, 36\n", READ_WIDTH_A);
-        #1 $stop ;
+        $fatal(1,"\nError: TDP_RAM36K instance %m has parameter READ_WIDTH_A set to %d.  Valid values are 1, 2, 4, 9, 18, 36\n", READ_WIDTH_A);
       end
     endcase
     case(WRITE_WIDTH_B)
@@ -512,8 +510,7 @@ module TDP_RAM36K #(
       18 ,
       36: begin end
       default: begin
-        $display("\nError: TDP_RAM36K instance %m has parameter WRITE_WIDTH_B set to %d.  Valid values are 1, 2, 4, 9, 18, 36\n", WRITE_WIDTH_B);
-        #1 $stop ;
+        $fatal(1,"\nError: TDP_RAM36K instance %m has parameter WRITE_WIDTH_B set to %d.  Valid values are 1, 2, 4, 9, 18, 36\n", WRITE_WIDTH_B);
       end
     endcase
     case(READ_WIDTH_B)
@@ -524,8 +521,7 @@ module TDP_RAM36K #(
       18 ,
       36: begin end
       default: begin
-        $display("\nError: TDP_RAM36K instance %m has parameter READ_WIDTH_B set to %d.  Valid values are 1, 2, 4, 9, 18, 36\n", READ_WIDTH_B);
-        #1 $stop ;
+        $fatal(1,"\nError: TDP_RAM36K instance %m has parameter READ_WIDTH_B set to %d.  Valid values are 1, 2, 4, 9, 18, 36\n", READ_WIDTH_B);
       end
     endcase
 
diff --git a/models_internal/verilog/BOOT_CLOCK.v b/models_internal/verilog/BOOT_CLOCK.v
index de276cb..07fcf82 100644
--- a/models_internal/verilog/BOOT_CLOCK.v
+++ b/models_internal/verilog/BOOT_CLOCK.v
@@ -20,8 +20,7 @@ localparam HALF_PERIOD = PERIOD/2.0;
  initial begin
 
     if ((PERIOD < 16.0) || (PERIOD > 30.0)) begin
-       $display("BOOT_CLOCK instance %m PERIOD set to incorrect value, %f.  Values must be between 16.0 and 30.0.", PERIOD);
-    #1 $stop;
+       $fatal(1,"BOOT_CLOCK instance %m PERIOD set to incorrect value, %f.  Values must be between 16.0 and 30.0.", PERIOD);
     end
 
   end
diff --git a/models_internal/verilog/DSP19X2.v b/models_internal/verilog/DSP19X2.v
index 26018a3..044b655 100644
--- a/models_internal/verilog/DSP19X2.v
+++ b/models_internal/verilog/DSP19X2.v
@@ -381,15 +381,13 @@ module DSP19X2 #(
 	always @(ACC_FIR)
 		if (ACC_FIR > 21)
 		begin
-			$display("WARNING: DSP19x2 instance %m ACC_FIR input is %d which is greater than 21 which serves no function", ACC_FIR);
-			#1 $finish ;
+			$fatal(1,"WARNING: DSP19x2 instance %m ACC_FIR input is %d which is greater than 21 which serves no function", ACC_FIR);
 		end
 	// If SHIFT_RIGHT is greater than 31, result is invalid
 	always @(SHIFT_RIGHT)
 		if (SHIFT_RIGHT > 31)
 		begin
-			$display("WARNING: DSP19x2 instance %m SHIFT_RIGHT input is %d which is greater than 31 which serves no function", SHIFT_RIGHT);
-			#1 $finish ;
+			$fatal(1,"WARNING: DSP19x2 instance %m SHIFT_RIGHT input is %d which is greater than 31 which serves no function", SHIFT_RIGHT);
 		end
 	
 	always@(*) 
@@ -397,7 +395,7 @@ module DSP19X2 #(
 		case(DSP_MODE)
 			"MULTIPLY_ACCUMULATE": begin  
 				if(FEEDBACK>1)
-					$display("\nWARNING: DSP19x2 instance %m has parameter DSP_MODE set to %s and FEEDBACK set to %0d. Valid values of FEEDBACK for this mode are 0,1 \n", DSP_MODE,FEEDBACK);
+					$fatal(1,"\nWARNING: DSP19x2 instance %m has parameter DSP_MODE set to %s and FEEDBACK set to %0d. Valid values of FEEDBACK for this mode are 0,1 \n", DSP_MODE,FEEDBACK);
 			end
 		endcase
 		
@@ -409,24 +407,21 @@ module DSP19X2 #(
       "MULTIPLY_ADD_SUB" ,
       "MULTIPLY_ACCUMULATE": begin end
       default: begin
-        $display("\nError: DSP19X2 instance %m has parameter DSP_MODE set to %s.  Valid values are MULTIPLY, MULTIPLY_ADD_SUB, MULTIPLY_ACCUMULATE\n", DSP_MODE);
-        #1 $stop ;
+        $fatal(1,"\nError: DSP19X2 instance %m has parameter DSP_MODE set to %s.  Valid values are MULTIPLY, MULTIPLY_ADD_SUB, MULTIPLY_ACCUMULATE\n", DSP_MODE);
       end
     endcase
     case(OUTPUT_REG_EN)
       "TRUE" ,
       "FALSE": begin end
       default: begin
-        $display("\nError: DSP19X2 instance %m has parameter OUTPUT_REG_EN set to %s.  Valid values are TRUE, FALSE\n", OUTPUT_REG_EN);
-        #1 $stop ;
+        $fatal(1,"\nError: DSP19X2 instance %m has parameter OUTPUT_REG_EN set to %s.  Valid values are TRUE, FALSE\n", OUTPUT_REG_EN);
       end
     endcase
     case(INPUT_REG_EN)
       "TRUE" ,
       "FALSE": begin end
       default: begin
-        $display("\nError: DSP19X2 instance %m has parameter INPUT_REG_EN set to %s.  Valid values are TRUE, FALSE\n", INPUT_REG_EN);
-        #1 $stop ;
+        $fatal(1,"\nError: DSP19X2 instance %m has parameter INPUT_REG_EN set to %s.  Valid values are TRUE, FALSE\n", INPUT_REG_EN);
       end
     endcase
 
diff --git a/models_internal/verilog/DSP38.v b/models_internal/verilog/DSP38.v
index b6a65fc..b91519c 100644
--- a/models_internal/verilog/DSP38.v
+++ b/models_internal/verilog/DSP38.v
@@ -297,14 +297,14 @@ module DSP38 #(
 	// If ACC_FIR is greater than 43, result is invalid
 	always @(ACC_FIR)
 		if (ACC_FIR > 43)
-			$display("WARNING: DSP38 instance %m ACC_FIR input is %d which is greater than 43 which serves no function", ACC_FIR);
+			$fatal(1,"\nWARNING: DSP38 instance %m ACC_FIR input is %d which is greater than 43 which serves no function", ACC_FIR);
 
 	always@(*) 
 	begin
 		case(DSP_MODE)
 			"MULTIPLY_ACCUMULATE": begin  
 				if(FEEDBACK>1)
-					$display("\nWARNING: DSP38 instance %m has parameter DSP_MODE set to %s and FEEDBACK set to %0d. Valid values of FEEDBACK for this mode are 0,1 \n", DSP_MODE,FEEDBACK);
+					$fatal(1,"\nWARNING: DSP38 instance %m has parameter DSP_MODE set to %s and FEEDBACK set to %0d. Valid values of FEEDBACK for this mode are 0,1 \n", DSP_MODE,FEEDBACK);
 			end
 		endcase
 		
@@ -316,24 +316,21 @@ module DSP38 #(
       "MULTIPLY_ADD_SUB" ,
       "MULTIPLY_ACCUMULATE": begin end
       default: begin
-        $display("\nError: DSP38 instance %m has parameter DSP_MODE set to %s.  Valid values are MULTIPLY, MULTIPLY_ADD_SUB, MULTIPLY_ACCUMULATE\n", DSP_MODE);
-        #1 $stop ;
+        $fatal(1,"\nError: DSP38 instance %m has parameter DSP_MODE set to %s.  Valid values are MULTIPLY, MULTIPLY_ADD_SUB, MULTIPLY_ACCUMULATE\n", DSP_MODE);
       end
     endcase
     case(OUTPUT_REG_EN)
       "TRUE" ,
       "FALSE": begin end
       default: begin
-        $display("\nError: DSP38 instance %m has parameter OUTPUT_REG_EN set to %s.  Valid values are TRUE, FALSE\n", OUTPUT_REG_EN);
-        #1 $stop ;
+        $fatal(1,"\nError: DSP38 instance %m has parameter OUTPUT_REG_EN set to %s.  Valid values are TRUE, FALSE\n", OUTPUT_REG_EN);
       end
     endcase
     case(INPUT_REG_EN)
       "TRUE" ,
       "FALSE": begin end
       default: begin
-        $display("\nError: DSP38 instance %m has parameter INPUT_REG_EN set to %s.  Valid values are TRUE, FALSE\n", INPUT_REG_EN);
-        #1 $stop ;
+        $fatal(1,"\nError: DSP38 instance %m has parameter INPUT_REG_EN set to %s.  Valid values are TRUE, FALSE\n", INPUT_REG_EN);
       end
     endcase
 
diff --git a/models_internal/verilog/FIFO18KX2.v b/models_internal/verilog/FIFO18KX2.v
index 62b8e89..8109b6d 100644
--- a/models_internal/verilog/FIFO18KX2.v
+++ b/models_internal/verilog/FIFO18KX2.v
@@ -337,48 +337,42 @@ tdp_ram18kx2_inst
       9 ,
       18: begin end
       default: begin
-        $display("\nError: FIFO18KX2 instance %m has parameter DATA_WRITE_WIDTH1 set to %d.  Valid values are 9, 18\n", DATA_WRITE_WIDTH1);
-        #1 $stop ;
+        $fatal(1,"\nError: FIFO18KX2 instance %m has parameter DATA_WRITE_WIDTH1 set to %d.  Valid values are 9, 18\n", DATA_WRITE_WIDTH1);
       end
     endcase
     case(DATA_READ_WIDTH1)
       9 ,
       18: begin end
       default: begin
-        $display("\nError: FIFO18KX2 instance %m has parameter DATA_READ_WIDTH1 set to %d.  Valid values are 9, 18\n", DATA_READ_WIDTH1);
-        #1 $stop ;
+        $fatal(1,"\nError: FIFO18KX2 instance %m has parameter DATA_READ_WIDTH1 set to %d.  Valid values are 9, 18\n", DATA_READ_WIDTH1);
       end
     endcase
     case(FIFO_TYPE1)
       "SYNCHRONOUS" ,
       "ASYNCHRONOUS": begin end
       default: begin
-        $display("\nError: FIFO18KX2 instance %m has parameter FIFO_TYPE1 set to %s.  Valid values are SYNCHRONOUS, ASYNCHRONOUS\n", FIFO_TYPE1);
-        #1 $stop ;
+        $fatal(1,"\nError: FIFO18KX2 instance %m has parameter FIFO_TYPE1 set to %s.  Valid values are SYNCHRONOUS, ASYNCHRONOUS\n", FIFO_TYPE1);
       end
     endcase
     case(DATA_WRITE_WIDTH2)
       9 ,
       18: begin end
       default: begin
-        $display("\nError: FIFO18KX2 instance %m has parameter DATA_WRITE_WIDTH2 set to %d.  Valid values are 9, 18\n", DATA_WRITE_WIDTH2);
-        #1 $stop ;
+        $fatal(1,"\nError: FIFO18KX2 instance %m has parameter DATA_WRITE_WIDTH2 set to %d.  Valid values are 9, 18\n", DATA_WRITE_WIDTH2);
       end
     endcase
     case(DATA_READ_WIDTH2)
       9 ,
       18: begin end
       default: begin
-        $display("\nError: FIFO18KX2 instance %m has parameter DATA_READ_WIDTH2 set to %d.  Valid values are 9, 18\n", DATA_READ_WIDTH2);
-        #1 $stop ;
+        $fatal(1,"\nError: FIFO18KX2 instance %m has parameter DATA_READ_WIDTH2 set to %d.  Valid values are 9, 18\n", DATA_READ_WIDTH2);
       end
     endcase
     case(FIFO_TYPE2)
       "SYNCHRONOUS" ,
       "ASYNCHRONOUS": begin end
       default: begin
-        $display("\nError: FIFO18KX2 instance %m has parameter FIFO_TYPE2 set to %s.  Valid values are SYNCHRONOUS, ASYNCHRONOUS\n", FIFO_TYPE2);
-        #1 $stop ;
+        $fatal(1,"\nError: FIFO18KX2 instance %m has parameter FIFO_TYPE2 set to %s.  Valid values are SYNCHRONOUS, ASYNCHRONOUS\n", FIFO_TYPE2);
       end
     endcase
 
diff --git a/models_internal/verilog/FIFO36K.v b/models_internal/verilog/FIFO36K.v
index 43c0643..c23d16c 100644
--- a/models_internal/verilog/FIFO36K.v
+++ b/models_internal/verilog/FIFO36K.v
@@ -202,8 +202,7 @@ module FIFO36K #(
       18 ,
       36: begin end
       default: begin
-        $display("\nError: FIFO36K instance %m has parameter DATA_WRITE_WIDTH set to %d.  Valid values are 9, 18, 36\n", DATA_WRITE_WIDTH);
-        #1 $stop ;
+        $fatal(1,"\nError: FIFO36K instance %m has parameter DATA_WRITE_WIDTH set to %d.  Valid values are 9, 18, 36\n", DATA_WRITE_WIDTH);
       end
     endcase
     case(DATA_READ_WIDTH)
@@ -211,16 +210,14 @@ module FIFO36K #(
       18 ,
       36: begin end
       default: begin
-        $display("\nError: FIFO36K instance %m has parameter DATA_READ_WIDTH set to %d.  Valid values are 9, 18, 36\n", DATA_READ_WIDTH);
-        #1 $stop ;
+        $fatal(1,"\nError: FIFO36K instance %m has parameter DATA_READ_WIDTH set to %d.  Valid values are 9, 18, 36\n", DATA_READ_WIDTH);
       end
     endcase
     case(FIFO_TYPE)
       "SYNCHRONOUS" ,
       "ASYNCHRONOUS": begin end
       default: begin
-        $display("\nError: FIFO36K instance %m has parameter FIFO_TYPE set to %s.  Valid values are SYNCHRONOUS, ASYNCHRONOUS\n", FIFO_TYPE);
-        #1 $stop ;
+        $fatal(1,"\nError: FIFO36K instance %m has parameter FIFO_TYPE set to %s.  Valid values are SYNCHRONOUS, ASYNCHRONOUS\n", FIFO_TYPE);
       end
     endcase
 
diff --git a/models_internal/verilog/I_BUF.v b/models_internal/verilog/I_BUF.v
index a24e411..f5825f5 100644
--- a/models_internal/verilog/I_BUF.v
+++ b/models_internal/verilog/I_BUF.v
@@ -34,8 +34,7 @@ module I_BUF #(
       "PULLUP" ,
       "PULLDOWN": begin end
       default: begin
-        $display("\nError: I_BUF instance %m has parameter WEAK_KEEPER set to %s.  Valid values are NONE, PULLUP, PULLDOWN\n", WEAK_KEEPER);
-        #1 $stop ;
+        $fatal(1,"\nError: I_BUF instance %m has parameter WEAK_KEEPER set to %s.  Valid values are NONE, PULLUP, PULLDOWN\n", WEAK_KEEPER);
       end
     endcase
 
@@ -69,8 +68,7 @@ module I_BUF #(
       "SSTL_I_33" ,
       "SSTL_II_33": begin end
       default: begin
-        $display("\nError: I_BUF instance %m has parameter IOSTANDARD set to %s.  Valid values are DEFAULT, LVCMOS_12, LVCMOS_15, LVCMOS_18_HP, LVCMOS_18_HR, LVCMOS_25, LVCMOS_33, LVTTL, HSTL_I_12, HSTL_II_12, HSTL_I_15, HSTL_II_15, HSUL_12, PCI66, PCIX133, POD_12, SSTL_I_15, SSTL_II_15, SSTL_I_18_HP, SSTL_II_18_HP, SSTL_I_18_HR, SSTL_II_18_HR, SSTL_I_25, SSTL_II_25, SSTL_I_33, SSTL_II_33\n", IOSTANDARD);
-        #1 $stop ;
+        $fatal(1,"\nError: I_BUF instance %m has parameter IOSTANDARD set to %s.  Valid values are DEFAULT, LVCMOS_12, LVCMOS_15, LVCMOS_18_HP, LVCMOS_18_HR, LVCMOS_25, LVCMOS_33, LVTTL, HSTL_I_12, HSTL_II_12, HSTL_I_15, HSTL_II_15, HSUL_12, PCI66, PCIX133, POD_12, SSTL_I_15, SSTL_II_15, SSTL_I_18_HP, SSTL_II_18_HP, SSTL_I_18_HR, SSTL_II_18_HR, SSTL_I_25, SSTL_II_25, SSTL_I_33, SSTL_II_33\n", IOSTANDARD);
       end
     endcase
 `endif // RAPIDSILICON_INTERNAL
diff --git a/models_internal/verilog/I_BUF_DS.v b/models_internal/verilog/I_BUF_DS.v
index 990598a..8041c7c 100644
--- a/models_internal/verilog/I_BUF_DS.v
+++ b/models_internal/verilog/I_BUF_DS.v
@@ -44,8 +44,7 @@ module I_BUF_DS #(
       "PULLUP" ,
       "PULLDOWN": begin end
       default: begin
-        $display("\nError: I_BUF_DS instance %m has parameter WEAK_KEEPER set to %s.  Valid values are NONE, PULLUP, PULLDOWN\n", WEAK_KEEPER);
-        #1 $stop ;
+        $fatal(1,"\nError: I_BUF_DS instance %m has parameter WEAK_KEEPER set to %s.  Valid values are NONE, PULLUP, PULLDOWN\n", WEAK_KEEPER);
       end
     endcase
     case(IOSTANDARD)
@@ -66,16 +65,14 @@ module I_BUF_DS #(
       "SSTL_18_HP_DIFF" ,
       "SSTL_18_HR_DIFF": begin end
       default: begin
-        $display("\nError: I_BUF_DS instance %m has parameter IOSTANDARD set to %s.  Valid values are DEFAULT, BLVDS_DIFF, LVDS_HP_DIFF, LVDS_HR_DIFF, LVPECL_25_DIFF, LVPECL_33_DIFF, HSTL_12_DIFF, HSTL_15_DIFF, HSUL_12_DIFF, MIPI_DIFF, POD_12_DIFF, RSDS_DIFF, SLVS_DIFF, SSTL_15_DIFF, SSTL_18_HP_DIFF, SSTL_18_HR_DIFF\n", IOSTANDARD);
-        #1 $stop ;
+        $fatal(1,"\nError: I_BUF_DS instance %m has parameter IOSTANDARD set to %s.  Valid values are DEFAULT, BLVDS_DIFF, LVDS_HP_DIFF, LVDS_HR_DIFF, LVPECL_25_DIFF, LVPECL_33_DIFF, HSTL_12_DIFF, HSTL_15_DIFF, HSUL_12_DIFF, MIPI_DIFF, POD_12_DIFF, RSDS_DIFF, SLVS_DIFF, SSTL_15_DIFF, SSTL_18_HP_DIFF, SSTL_18_HR_DIFF\n", IOSTANDARD);
       end
     endcase
     case(DIFFERENTIAL_TERMINATION)
       "TRUE" ,
       "FALSE": begin end
       default: begin
-        $display("\nError: I_BUF_DS instance %m has parameter DIFFERENTIAL_TERMINATION set to %s.  Valid values are TRUE, FALSE\n", DIFFERENTIAL_TERMINATION);
-        #1 $stop ;
+        $fatal(1,"\nError: I_BUF_DS instance %m has parameter DIFFERENTIAL_TERMINATION set to %s.  Valid values are TRUE, FALSE\n", DIFFERENTIAL_TERMINATION);
       end
     endcase
 
diff --git a/models_internal/verilog/I_DELAY.v b/models_internal/verilog/I_DELAY.v
index b9690b2..bd8f6b5 100644
--- a/models_internal/verilog/I_DELAY.v
+++ b/models_internal/verilog/I_DELAY.v
@@ -59,8 +59,7 @@ assign #(30.0ps + (21.56ps*dly_tap_val)) O = I;			// Adjusted Delay for TT corne
  initial begin
 
     if ((DELAY < 0) || (DELAY > 63)) begin
-       $display("I_DELAY instance %m DELAY set to incorrect value, %d.  Values must be between 0 and 63.", DELAY);
-    #1 $stop;
+       $fatal(1,"I_DELAY instance %m DELAY set to incorrect value, %d.  Values must be between 0 and 63.", DELAY);
     end
 
   end
diff --git a/models_internal/verilog/I_FAB.v b/models_internal/verilog/I_FAB.v
new file mode 100644
index 0000000..a69b17e
--- /dev/null
+++ b/models_internal/verilog/I_FAB.v
@@ -0,0 +1,19 @@
+`timescale 1ns/1ps
+`celldefine
+//
+// I_FAB simulation model
+// Marker Buffer for periphery to fabric transition
+//
+// Copyright (c) 2023 Rapid Silicon, Inc.  All rights reserved.
+//
+
+module I_FAB (
+  input I, // Input
+  output O // Output
+);
+
+assign O = I ;
+
+
+endmodule
+`endcelldefine
diff --git a/models_internal/verilog/I_SERDES.v b/models_internal/verilog/I_SERDES.v
index a9078dd..76061d7 100644
--- a/models_internal/verilog/I_SERDES.v
+++ b/models_internal/verilog/I_SERDES.v
@@ -758,22 +758,19 @@ assign DATA_VALID=!des_fifo_empty;
       "SDR" ,
       "DDR": begin end
       default: begin
-        $display("\nError: I_SERDES instance %m has parameter DATA_RATE set to %s.  Valid values are SDR, DDR\n", DATA_RATE);
-        #1 $stop ;
+        $fatal(1,"\nError: I_SERDES instance %m has parameter DATA_RATE set to %s.  Valid values are SDR, DDR\n", DATA_RATE);
       end
     endcase
 
     if ((WIDTH < 3) || (WIDTH > 10)) begin
-       $display("I_SERDES instance %m WIDTH set to incorrect value, %d.  Values must be between 3 and 10.", WIDTH);
-    #1 $stop;
+       $fatal(1,"I_SERDES instance %m WIDTH set to incorrect value, %d.  Values must be between 3 and 10.", WIDTH);
     end
     case(DPA_MODE)
       "NONE" ,
       "DPA" ,
       "CDR": begin end
       default: begin
-        $display("\nError: I_SERDES instance %m has parameter DPA_MODE set to %s.  Valid values are NONE, DPA, CDR\n", DPA_MODE);
-        #1 $stop ;
+        $fatal(1,"\nError: I_SERDES instance %m has parameter DPA_MODE set to %s.  Valid values are NONE, DPA, CDR\n", DPA_MODE);
       end
     endcase
 
diff --git a/models_internal/verilog/O_BUF.v b/models_internal/verilog/O_BUF.v
index 9224497..c32ed9d 100644
--- a/models_internal/verilog/O_BUF.v
+++ b/models_internal/verilog/O_BUF.v
@@ -53,8 +53,7 @@ module O_BUF
       "SSTL_I_33" ,
       "SSTL_II_33": begin end
       default: begin
-        $display("\nError: O_BUF instance %m has parameter IOSTANDARD set to %s.  Valid values are DEFAULT, LVCMOS_12, LVCMOS_15, LVCMOS_18_HP, LVCMOS_18_HR, LVCMOS_25, LVCMOS_33, LVTTL, HSTL_I_12, HSTL_II_12, HSTL_I_15, HSTL_II_15, HSUL_12, PCI66, PCIX133, POD_12, SSTL_I_15, SSTL_II_15, SSTL_I_18_HP, SSTL_II_18_HP, SSTL_I_18_HR, SSTL_II_18_HR, SSTL_I_25, SSTL_II_25, SSTL_I_33, SSTL_II_33\n", IOSTANDARD);
-        #1 $stop ;
+        $fatal(1,"\nError: O_BUF instance %m has parameter IOSTANDARD set to %s.  Valid values are DEFAULT, LVCMOS_12, LVCMOS_15, LVCMOS_18_HP, LVCMOS_18_HR, LVCMOS_25, LVCMOS_33, LVTTL, HSTL_I_12, HSTL_II_12, HSTL_I_15, HSTL_II_15, HSUL_12, PCI66, PCIX133, POD_12, SSTL_I_15, SSTL_II_15, SSTL_I_18_HP, SSTL_II_18_HP, SSTL_I_18_HR, SSTL_II_18_HR, SSTL_I_25, SSTL_II_25, SSTL_I_33, SSTL_II_33\n", IOSTANDARD);
       end
     endcase
 
@@ -66,8 +65,7 @@ module O_BUF
       12 ,
       16: begin end
       default: begin
-        $display("\nError: O_BUF instance %m has parameter DRIVE_STRENGTH set to %s.  Valid values are 2, 4, 6, 8, 12, 16\n", DRIVE_STRENGTH);
-        #1 $stop ;
+        $fatal(1,"\nError: O_BUF instance %m has parameter DRIVE_STRENGTH set to %s.  Valid values are 2, 4, 6, 8, 12, 16\n", DRIVE_STRENGTH);
       end
     endcase
 
@@ -75,8 +73,7 @@ module O_BUF
       "SLOW" ,
       "FAST": begin end
       default: begin
-        $display("\nError: O_BUF instance %m has parameter SLEW_RATE set to %s.  Valid values are SLOW, FAST\n", SLEW_RATE);
-        #1 $stop ;
+        $fatal(1,"\nError: O_BUF instance %m has parameter SLEW_RATE set to %s.  Valid values are SLOW, FAST\n", SLEW_RATE);
       end
     endcase
 `endif // RAPIDSILICON_INTERNAL
diff --git a/models_internal/verilog/O_BUFT.v b/models_internal/verilog/O_BUFT.v
index 71bc8db..99dab80 100644
--- a/models_internal/verilog/O_BUFT.v
+++ b/models_internal/verilog/O_BUFT.v
@@ -36,8 +36,7 @@ module O_BUFT #(
       "PULLUP" ,
       "PULLDOWN": begin end
       default: begin
-        $display("\nError: O_BUFT instance %m has parameter WEAK_KEEPER set to %s.  Valid values are NONE, PULLUP, PULLDOWN\n", WEAK_KEEPER);
-        #1 $stop ;
+        $fatal(1,"\nError: O_BUFT instance %m has parameter WEAK_KEEPER set to %s.  Valid values are NONE, PULLUP, PULLDOWN\n", WEAK_KEEPER);
       end
     endcase
 
@@ -71,8 +70,7 @@ module O_BUFT #(
       "SSTL_I_33" ,
       "SSTL_II_33": begin end
       default: begin
-        $display("\nError: O_BUFT instance %m has parameter IOSTANDARD set to %s.  Valid values are DEFAULT, LVCMOS_12, LVCMOS_15, LVCMOS_18_HP, LVCMOS_18_HR, LVCMOS_25, LVCMOS_33, LVTTL, HSTL_I_12, HSTL_II_12, HSTL_I_15, HSTL_II_15, HSUL_12, PCI66, PCIX133, POD_12, SSTL_I_15, SSTL_II_15, SSTL_I_18_HP, SSTL_II_18_HP, SSTL_I_18_HR, SSTL_II_18_HR, SSTL_I_25, SSTL_II_25, SSTL_I_33, SSTL_II_33\n", IOSTANDARD);
-        #1 $stop ;
+        $fatal(1,"\nError: O_BUFT instance %m has parameter IOSTANDARD set to %s.  Valid values are DEFAULT, LVCMOS_12, LVCMOS_15, LVCMOS_18_HP, LVCMOS_18_HR, LVCMOS_25, LVCMOS_33, LVTTL, HSTL_I_12, HSTL_II_12, HSTL_I_15, HSTL_II_15, HSUL_12, PCI66, PCIX133, POD_12, SSTL_I_15, SSTL_II_15, SSTL_I_18_HP, SSTL_II_18_HP, SSTL_I_18_HR, SSTL_II_18_HR, SSTL_I_25, SSTL_II_25, SSTL_I_33, SSTL_II_33\n", IOSTANDARD);
       end
     endcase
 
@@ -84,8 +82,7 @@ module O_BUFT #(
       12 ,
       16: begin end
       default: begin
-        $display("\nError: O_BUFT instance %m has parameter DRIVE_STRENGTH set to %s.  Valid values are 2, 4, 6, 8, 12, 16\n", DRIVE_STRENGTH);
-        #1 $stop ;
+        $fatal(1,"\nError: O_BUFT instance %m has parameter DRIVE_STRENGTH set to %s.  Valid values are 2, 4, 6, 8, 12, 16\n", DRIVE_STRENGTH);
       end
     endcase
 
@@ -93,8 +90,7 @@ module O_BUFT #(
       "SLOW" ,
       "FAST": begin end
       default: begin
-        $display("\nError: O_BUFT instance %m has parameter SLEW_RATE set to %s.  Valid values are SLOW, FAST\n", SLEW_RATE);
-        #1 $stop ;
+        $fatal(1,"\nError: O_BUFT instance %m has parameter SLEW_RATE set to %s.  Valid values are SLOW, FAST\n", SLEW_RATE);
       end
     endcase
 `endif // RAPIDSILICON_INTERNAL
diff --git a/models_internal/verilog/O_BUFT_DS.v b/models_internal/verilog/O_BUFT_DS.v
index 0442bf6..a447497 100644
--- a/models_internal/verilog/O_BUFT_DS.v
+++ b/models_internal/verilog/O_BUFT_DS.v
@@ -39,8 +39,7 @@ module O_BUFT_DS #(
       "PULLUP" ,
       "PULLDOWN": begin end
       default: begin
-        $display("\nError: O_BUFT_DS instance %m has parameter WEAK_KEEPER set to %s.  Valid values are NONE, PULLUP, PULLDOWN\n", WEAK_KEEPER);
-        #1 $stop ;
+        $fatal(1,"\nError: O_BUFT_DS instance %m has parameter WEAK_KEEPER set to %s.  Valid values are NONE, PULLUP, PULLDOWN\n", WEAK_KEEPER);
       end
     endcase
 
@@ -64,8 +63,7 @@ module O_BUFT_DS #(
       "SSTL_18_HP_DIFF" ,
       "SSTL_18_HR_DIFF": begin end
       default: begin
-        $display("\nError: O_BUFT_DS instance %m has parameter IOSTANDARD set to %s.  Valid values are DEFAULT, BLVDS_DIFF, LVDS_HP_DIFF, LVDS_HR_DIFF, LVPECL_25_DIFF, LVPECL_33_DIFF, HSTL_12_DIFF, HSTL_15_DIFF, HSUL_12_DIFF, MIPI_DIFF, POD_12_DIFF, RSDS_DIFF, SLVS_DIFF, SSTL_15_DIFF, SSTL_18_HP_DIFF, SSTL_18_HR_DIFF\n", IOSTANDARD);
-        #1 $stop ;
+        $fatal(1,"\nError: O_BUFT_DS instance %m has parameter IOSTANDARD set to %s.  Valid values are DEFAULT, BLVDS_DIFF, LVDS_HP_DIFF, LVDS_HR_DIFF, LVPECL_25_DIFF, LVPECL_33_DIFF, HSTL_12_DIFF, HSTL_15_DIFF, HSUL_12_DIFF, MIPI_DIFF, POD_12_DIFF, RSDS_DIFF, SLVS_DIFF, SSTL_15_DIFF, SSTL_18_HP_DIFF, SSTL_18_HR_DIFF\n", IOSTANDARD);
       end
     endcase
 
@@ -73,8 +71,7 @@ module O_BUFT_DS #(
       "TRUE" ,
       "FALSE": begin end
       default: begin
-        $display("\nError: O_BUFT_DS instance %m has parameter DIFFERENTIAL_TERMINATION set to %s.  Valid values are TRUE, FALSE\n", DIFFERENTIAL_TERMINATION);
-        #1 $stop ;
+        $fatal(1,"\nError: O_BUFT_DS instance %m has parameter DIFFERENTIAL_TERMINATION set to %s.  Valid values are TRUE, FALSE\n", DIFFERENTIAL_TERMINATION);
       end
     endcase
 `endif // RAPIDSILICON_INTERNAL
diff --git a/models_internal/verilog/O_BUF_DS.v b/models_internal/verilog/O_BUF_DS.v
index 6971bc7..378b73e 100644
--- a/models_internal/verilog/O_BUF_DS.v
+++ b/models_internal/verilog/O_BUF_DS.v
@@ -45,8 +45,7 @@ module O_BUF_DS
       "SSTL_18_HP_DIFF" ,
       "SSTL_18_HR_DIFF": begin end
       default: begin
-        $display("\nError: O_BUF_DS instance %m has parameter IOSTANDARD set to %s.  Valid values are DEFAULT, BLVDS_DIFF, LVDS_HP_DIFF, LVDS_HR_DIFF, LVPECL_25_DIFF, LVPECL_33_DIFF, HSTL_12_DIFF, HSTL_15_DIFF, HSUL_12_DIFF, MIPI_DIFF, POD_12_DIFF, RSDS_DIFF, SLVS_DIFF, SSTL_15_DIFF, SSTL_18_HP_DIFF, SSTL_18_HR_DIFF\n", IOSTANDARD);
-        #1 $stop ;
+        $fatal(1,"\nError: O_BUF_DS instance %m has parameter IOSTANDARD set to %s.  Valid values are DEFAULT, BLVDS_DIFF, LVDS_HP_DIFF, LVDS_HR_DIFF, LVPECL_25_DIFF, LVPECL_33_DIFF, HSTL_12_DIFF, HSTL_15_DIFF, HSUL_12_DIFF, MIPI_DIFF, POD_12_DIFF, RSDS_DIFF, SLVS_DIFF, SSTL_15_DIFF, SSTL_18_HP_DIFF, SSTL_18_HR_DIFF\n", IOSTANDARD);
       end
     endcase
 
@@ -54,8 +53,7 @@ module O_BUF_DS
       "TRUE" ,
       "FALSE": begin end
       default: begin
-        $display("\nError: O_BUF_DS instance %m has parameter DIFFERENTIAL_TERMINATION set to %s.  Valid values are TRUE, FALSE\n", DIFFERENTIAL_TERMINATION);
-        #1 $stop ;
+        $fatal(1,"\nError: O_BUF_DS instance %m has parameter DIFFERENTIAL_TERMINATION set to %s.  Valid values are TRUE, FALSE\n", DIFFERENTIAL_TERMINATION);
       end
     endcase
 `endif // RAPIDSILICON_INTERNAL
diff --git a/models_internal/verilog/O_DELAY.v b/models_internal/verilog/O_DELAY.v
index 4bd98ae..470438d 100644
--- a/models_internal/verilog/O_DELAY.v
+++ b/models_internal/verilog/O_DELAY.v
@@ -59,8 +59,7 @@ assign #(30.0ps + (21.56ps*dly_tap_val)) O = I;				// Adjusted Delay for TT corn
  initial begin
 
     if ((DELAY < 0) || (DELAY > 63)) begin
-       $display("O_DELAY instance %m DELAY set to incorrect value, %d.  Values must be between 0 and 63.", DELAY);
-    #1 $stop;
+       $fatal(1,"O_DELAY instance %m DELAY set to incorrect value, %d.  Values must be between 0 and 63.", DELAY);
     end
 
   end
diff --git a/models_internal/verilog/O_FAB.v b/models_internal/verilog/O_FAB.v
new file mode 100644
index 0000000..956a0a2
--- /dev/null
+++ b/models_internal/verilog/O_FAB.v
@@ -0,0 +1,18 @@
+`timescale 1ns/1ps
+`celldefine
+//
+// O_FAB simulation model
+// Marker Buffer for fabric to periphery transition
+//
+// Copyright (c) 2023 Rapid Silicon, Inc.  All rights reserved.
+//
+
+module O_FAB (
+  input I, // Input
+  output O // Output
+);
+
+assign O = I ;
+
+endmodule
+`endcelldefine
diff --git a/models_internal/verilog/O_SERDES.v b/models_internal/verilog/O_SERDES.v
index b4996c9..482b693 100644
--- a/models_internal/verilog/O_SERDES.v
+++ b/models_internal/verilog/O_SERDES.v
@@ -244,14 +244,12 @@ module O_SERDES #(
       "SDR" ,
       "DDR": begin end
       default: begin
-        $display("\nError: O_SERDES instance %m has parameter DATA_RATE set to %s.  Valid values are SDR, DDR\n", DATA_RATE);
-        #1 $stop ;
+        $fatal(1,"\nError: O_SERDES instance %m has parameter DATA_RATE set to %s.  Valid values are SDR, DDR\n", DATA_RATE);
       end
     endcase
 
     if ((WIDTH < 3) || (WIDTH > 10)) begin
-       $display("O_SERDES instance %m WIDTH set to incorrect value, %d.  Values must be between 3 and 10.", WIDTH);
-    #1 $stop;
+       $fatal(1,"O_SERDES instance %m WIDTH set to incorrect value, %d.  Values must be between 3 and 10.", WIDTH);
     end
 
   end
diff --git a/models_internal/verilog/O_SERDES_CLK.v b/models_internal/verilog/O_SERDES_CLK.v
index cde9760..674d02f 100644
--- a/models_internal/verilog/O_SERDES_CLK.v
+++ b/models_internal/verilog/O_SERDES_CLK.v
@@ -53,8 +53,7 @@ module O_SERDES_CLK #(
       "SDR" ,
       "DDR": begin end
       default: begin
-        $display("\nError: O_SERDES_CLK instance %m has parameter DATA_RATE set to %s.  Valid values are SDR, DDR\n", DATA_RATE);
-        #1 $stop ;
+        $fatal(1,"\nError: O_SERDES_CLK instance %m has parameter DATA_RATE set to %s.  Valid values are SDR, DDR\n", DATA_RATE);
       end
     endcase
     case(CLOCK_PHASE)
@@ -63,8 +62,7 @@ module O_SERDES_CLK #(
       180 ,
       270: begin end
       default: begin
-        $display("\nError: O_SERDES_CLK instance %m has parameter CLOCK_PHASE set to %d.  Valid values are 0, 90, 180, 270\n", CLOCK_PHASE);
-        #1 $stop ;
+        $fatal(1,"\nError: O_SERDES_CLK instance %m has parameter CLOCK_PHASE set to %d.  Valid values are 0, 90, 180, 270\n", CLOCK_PHASE);
       end
     endcase
 
diff --git a/models_internal/verilog/PLL.v b/models_internal/verilog/PLL.v
index d3af947..1efcd89 100644
--- a/models_internal/verilog/PLL.v
+++ b/models_internal/verilog/PLL.v
@@ -160,12 +160,10 @@ localparam      FAST_LOCK      = 0; // Reduce lock time
 	always @ (posedge CLK_IN) begin
 		if(pllstart_ff2)begin
 			if (ref_period<VCO_MIN_PERIOD) begin
-				$display("\nError at time %t: PLL instance %m REF clock period %0d fs violates minimum period.\nMust be greater than %0d fs.\n", $realtime, ref_period, VCO_MIN_PERIOD);
-				$stop;
+				$fatal(1,"\nError at time %t: PLL instance %m REF clock period %0d fs violates minimum period.\nMust be greater than %0d fs.\n", $realtime, ref_period, VCO_MIN_PERIOD);
 			end
 			else if (ref_period>VCO_MAX_PERIOD) begin
-				$display("\nError at time %t: PLL instance %m REF clock period %0d fs violates maximum period.\nMust be less than %0d fs.\n", $realtime, ref_period, VCO_MAX_PERIOD);
-				$stop;
+				$fatal(1,"\nError at time %t: PLL instance %m REF clock period %0d fs violates maximum period.\nMust be less than %0d fs.\n", $realtime, ref_period, VCO_MAX_PERIOD);
 			end
 		end
 	end
@@ -182,12 +180,10 @@ localparam      FAST_LOCK      = 0; // Reduce lock time
 	always @ (posedge FAST_CLK) begin
 		if(vcostart_ff) begin
 			if (vco_period<VCO_MIN_PERIOD) begin
-				$display("\nError at time %t: PLL instance %m VCO clock period %0d fs violates minimum period.\nMust be greater than %0d fs.\nTry increasing PLL_DIV or decreasing PLL_MULT values.\n", $realtime, vco_period, VCO_MIN_PERIOD);
-				$stop;
+				$fatal(1,"\nError at time %t: PLL instance %m VCO clock period %0d fs violates minimum period.\nMust be greater than %0d fs.\nTry increasing PLL_DIV or decreasing PLL_MULT values.\n", $realtime, vco_period, VCO_MIN_PERIOD);
 			end
 			else if (vco_period>VCO_MAX_PERIOD) begin
-				$display("\nError at time %t: PLL instance %m VCO clock period %0d fs violates maximum period.\nMust be less than %0d fs.\nTry increasing PLL_MULT or decreasing PLL_DIV values.\n", $realtime, vco_period, VCO_MAX_PERIOD);
-				$stop;
+				$fatal(1,"\nError at time %t: PLL instance %m VCO clock period %0d fs violates maximum period.\nMust be less than %0d fs.\nTry increasing PLL_MULT or decreasing PLL_DIV values.\n", $realtime, vco_period, VCO_MAX_PERIOD);
 			end
 		end
 	end
@@ -198,19 +194,16 @@ localparam      FAST_LOCK      = 0; // Reduce lock time
 	always @ (posedge CLK_IN, posedge PLL_EN) begin
 		if(PLL_EN)begin
 			if(PLL_POST_DIV0==0)begin
-				$display("Error at time %t: \n \t PLL instance %m, PLL_POST_DIV0 is equal to zero.\n \t Must be greater than 0", $realtime);
-            $stop;
+				$fatal(1,"Error at time %t: \n \t PLL instance %m, PLL_POST_DIV0 is equal to zero.\n \t Must be greater than 0", $realtime);
 			end
 
 			else if(PLL_POST_DIV1==0)begin
-				$display("Error at time %t: \n \t PLL instance %m, PLL_POST_DIV1 is equal to zero.\n \t Must be greater than 0", $realtime);
-				$stop;
+				$fatal(1,"Error at time %t: \n \t PLL instance %m, PLL_POST_DIV1 is equal to zero.\n \t Must be greater than 0", $realtime);
 			end
 
 
 			else if(PLL_POST_DIV1>PLL_POST_DIV0) begin
-				$display("Error at time %t: PLL_POST_DIV1 > PLL_POST_DIV0\n", $realtime);
-				$stop;
+				$fatal(1,"Error at time %t: PLL_POST_DIV1 > PLL_POST_DIV0\n", $realtime);
 			end
 		end
 	end
@@ -219,33 +212,28 @@ localparam      FAST_LOCK      = 0; // Reduce lock time
     case(DEV_FAMILY)
       "VIRGO": begin end
       default: begin
-        $display("\nError: PLL instance %m has parameter DEV_FAMILY set to %s.  Valid values are VIRGO\n", DEV_FAMILY);
-        #1 $stop ;
+        $fatal(1,"\nError: PLL instance %m has parameter DEV_FAMILY set to %s.  Valid values are VIRGO\n", DEV_FAMILY);
       end
     endcase
     case(DIVIDE_CLK_IN_BY_2)
       "TRUE" ,
       "FALSE": begin end
       default: begin
-        $display("\nError: PLL instance %m has parameter DIVIDE_CLK_IN_BY_2 set to %s.  Valid values are TRUE, FALSE\n", DIVIDE_CLK_IN_BY_2);
-        #1 $stop ;
+        $fatal(1,"\nError: PLL instance %m has parameter DIVIDE_CLK_IN_BY_2 set to %s.  Valid values are TRUE, FALSE\n", DIVIDE_CLK_IN_BY_2);
       end
     endcase
 
     if ((PLL_MULT < 16) || (PLL_MULT > 640)) begin
-       $display("PLL instance %m PLL_MULT set to incorrect value, %d.  Values must be between 16 and 640.", PLL_MULT);
-    #1 $stop;
+       $fatal(1,"PLL instance %m PLL_MULT set to incorrect value, %d.  Values must be between 16 and 640.", PLL_MULT);
     end
 
     if ((PLL_DIV < 1) || (PLL_DIV > 63)) begin
-       $display("PLL instance %m PLL_DIV set to incorrect value, %d.  Values must be between 1 and 63.", PLL_DIV);
-    #1 $stop;
+       $fatal(1,"PLL instance %m PLL_DIV set to incorrect value, %d.  Values must be between 1 and 63.", PLL_DIV);
     end
     case(PLL_MULT_FRAC)
       0: begin end
       default: begin
-        $display("\nError: PLL instance %m has parameter PLL_MULT_FRAC set to %d.  Valid values are 0\n", PLL_MULT_FRAC);
-        #1 $stop ;
+        $fatal(1,"\nError: PLL instance %m has parameter PLL_MULT_FRAC set to %d.  Valid values are 0\n", PLL_MULT_FRAC);
       end
     endcase
     case(PLL_POST_DIV)
@@ -278,8 +266,7 @@ localparam      FAST_LOCK      = 0; // Reduce lock time
       103 ,
       119: begin end
       default: begin
-        $display("\nError: PLL instance %m has parameter PLL_POST_DIV set to %d.  Valid values are 17, 18, 19, 20, 21, 22, 23, 34, 35, 36, 37, 38, 39, 51, 52, 53, 54, 55, 68, 69, 70, 71, 85, 86, 87, 102, 103, 119\n", PLL_POST_DIV);
-        #1 $stop ;
+        $fatal(1,"\nError: PLL instance %m has parameter PLL_POST_DIV set to %d.  Valid values are 17, 18, 19, 20, 21, 22, 23, 34, 35, 36, 37, 38, 39, 51, 52, 53, 54, 55, 68, 69, 70, 71, 85, 86, 87, 102, 103, 119\n", PLL_POST_DIV);
       end
     endcase
 
diff --git a/models_internal/verilog/SOC_FPGA_TEMPERATURE.v b/models_internal/verilog/SOC_FPGA_TEMPERATURE.v
index 23ea46a..67727a0 100644
--- a/models_internal/verilog/SOC_FPGA_TEMPERATURE.v
+++ b/models_internal/verilog/SOC_FPGA_TEMPERATURE.v
@@ -71,8 +71,7 @@ module SOC_FPGA_TEMPERATURE #(
  initial begin
 
     if ((INITIAL_TEMPERATURE < 0) || (INITIAL_TEMPERATURE > 125)) begin
-       $display("SOC_FPGA_TEMPERATURE instance %m INITIAL_TEMPERATURE set to incorrect value, %d.  Values must be between 0 and 125.", INITIAL_TEMPERATURE);
-    #1 $stop;
+       $fatal(1,"SOC_FPGA_TEMPERATURE instance %m INITIAL_TEMPERATURE set to incorrect value, %d.  Values must be between 0 and 125.", INITIAL_TEMPERATURE);
     end
 
   end
diff --git a/models_internal/verilog/TDP_RAM18KX2.v b/models_internal/verilog/TDP_RAM18KX2.v
index d8e96a7..afd8d7a 100644
--- a/models_internal/verilog/TDP_RAM18KX2.v
+++ b/models_internal/verilog/TDP_RAM18KX2.v
@@ -844,8 +844,7 @@ module TDP_RAM18KX2 #(
       9 ,
       18: begin end
       default: begin
-        $display("\nError: TDP_RAM18KX2 instance %m has parameter WRITE_WIDTH_A1 set to %d.  Valid values are 1, 2, 4, 9, 18\n", WRITE_WIDTH_A1);
-        #1 $stop ;
+        $fatal(1,"\nError: TDP_RAM18KX2 instance %m has parameter WRITE_WIDTH_A1 set to %d.  Valid values are 1, 2, 4, 9, 18\n", WRITE_WIDTH_A1);
       end
     endcase
     case(WRITE_WIDTH_B1)
@@ -855,8 +854,7 @@ module TDP_RAM18KX2 #(
       9 ,
       18: begin end
       default: begin
-        $display("\nError: TDP_RAM18KX2 instance %m has parameter WRITE_WIDTH_B1 set to %d.  Valid values are 1, 2, 4, 9, 18\n", WRITE_WIDTH_B1);
-        #1 $stop ;
+        $fatal(1,"\nError: TDP_RAM18KX2 instance %m has parameter WRITE_WIDTH_B1 set to %d.  Valid values are 1, 2, 4, 9, 18\n", WRITE_WIDTH_B1);
       end
     endcase
     case(READ_WIDTH_A1)
@@ -866,8 +864,7 @@ module TDP_RAM18KX2 #(
       9 ,
       18: begin end
       default: begin
-        $display("\nError: TDP_RAM18KX2 instance %m has parameter READ_WIDTH_A1 set to %d.  Valid values are 1, 2, 4, 9, 18\n", READ_WIDTH_A1);
-        #1 $stop ;
+        $fatal(1,"\nError: TDP_RAM18KX2 instance %m has parameter READ_WIDTH_A1 set to %d.  Valid values are 1, 2, 4, 9, 18\n", READ_WIDTH_A1);
       end
     endcase
     case(READ_WIDTH_B1)
@@ -877,8 +874,7 @@ module TDP_RAM18KX2 #(
       9 ,
       18: begin end
       default: begin
-        $display("\nError: TDP_RAM18KX2 instance %m has parameter READ_WIDTH_B1 set to %d.  Valid values are 1, 2, 4, 9, 18\n", READ_WIDTH_B1);
-        #1 $stop ;
+        $fatal(1,"\nError: TDP_RAM18KX2 instance %m has parameter READ_WIDTH_B1 set to %d.  Valid values are 1, 2, 4, 9, 18\n", READ_WIDTH_B1);
       end
     endcase
     case(WRITE_WIDTH_A2)
@@ -888,8 +884,7 @@ module TDP_RAM18KX2 #(
       9 ,
       18: begin end
       default: begin
-        $display("\nError: TDP_RAM18KX2 instance %m has parameter WRITE_WIDTH_A2 set to %d.  Valid values are 1, 2, 4, 9, 18\n", WRITE_WIDTH_A2);
-        #1 $stop ;
+        $fatal(1,"\nError: TDP_RAM18KX2 instance %m has parameter WRITE_WIDTH_A2 set to %d.  Valid values are 1, 2, 4, 9, 18\n", WRITE_WIDTH_A2);
       end
     endcase
     case(WRITE_WIDTH_B2)
@@ -899,8 +894,7 @@ module TDP_RAM18KX2 #(
       9 ,
       18: begin end
       default: begin
-        $display("\nError: TDP_RAM18KX2 instance %m has parameter WRITE_WIDTH_B2 set to %d.  Valid values are 1, 2, 4, 9, 18\n", WRITE_WIDTH_B2);
-        #1 $stop ;
+        $fatal(1,"\nError: TDP_RAM18KX2 instance %m has parameter WRITE_WIDTH_B2 set to %d.  Valid values are 1, 2, 4, 9, 18\n", WRITE_WIDTH_B2);
       end
     endcase
     case(READ_WIDTH_A2)
@@ -910,8 +904,7 @@ module TDP_RAM18KX2 #(
       9 ,
       18: begin end
       default: begin
-        $display("\nError: TDP_RAM18KX2 instance %m has parameter READ_WIDTH_A2 set to %d.  Valid values are 1, 2, 4, 9, 18\n", READ_WIDTH_A2);
-        #1 $stop ;
+        $fatal(1,"\nError: TDP_RAM18KX2 instance %m has parameter READ_WIDTH_A2 set to %d.  Valid values are 1, 2, 4, 9, 18\n", READ_WIDTH_A2);
       end
     endcase
     case(READ_WIDTH_B2)
@@ -921,8 +914,7 @@ module TDP_RAM18KX2 #(
       9 ,
       18: begin end
       default: begin
-        $display("\nError: TDP_RAM18KX2 instance %m has parameter READ_WIDTH_B2 set to %d.  Valid values are 1, 2, 4, 9, 18\n", READ_WIDTH_B2);
-        #1 $stop ;
+        $fatal(1,"\nError: TDP_RAM18KX2 instance %m has parameter READ_WIDTH_B2 set to %d.  Valid values are 1, 2, 4, 9, 18\n", READ_WIDTH_B2);
       end
     endcase
 
diff --git a/models_internal/verilog/TDP_RAM36K.v b/models_internal/verilog/TDP_RAM36K.v
index 78c88e9..12bda78 100644
--- a/models_internal/verilog/TDP_RAM36K.v
+++ b/models_internal/verilog/TDP_RAM36K.v
@@ -488,8 +488,7 @@ module TDP_RAM36K #(
       18 ,
       36: begin end
       default: begin
-        $display("\nError: TDP_RAM36K instance %m has parameter WRITE_WIDTH_A set to %d.  Valid values are 1, 2, 4, 9, 18, 36\n", WRITE_WIDTH_A);
-        #1 $stop ;
+        $fatal(1,"\nError: TDP_RAM36K instance %m has parameter WRITE_WIDTH_A set to %d.  Valid values are 1, 2, 4, 9, 18, 36\n", WRITE_WIDTH_A);
       end
     endcase
     case(READ_WIDTH_A)
@@ -500,8 +499,7 @@ module TDP_RAM36K #(
       18 ,
       36: begin end
       default: begin
-        $display("\nError: TDP_RAM36K instance %m has parameter READ_WIDTH_A set to %d.  Valid values are 1, 2, 4, 9, 18, 36\n", READ_WIDTH_A);
-        #1 $stop ;
+        $fatal(1,"\nError: TDP_RAM36K instance %m has parameter READ_WIDTH_A set to %d.  Valid values are 1, 2, 4, 9, 18, 36\n", READ_WIDTH_A);
       end
     endcase
     case(WRITE_WIDTH_B)
@@ -512,8 +510,7 @@ module TDP_RAM36K #(
       18 ,
       36: begin end
       default: begin
-        $display("\nError: TDP_RAM36K instance %m has parameter WRITE_WIDTH_B set to %d.  Valid values are 1, 2, 4, 9, 18, 36\n", WRITE_WIDTH_B);
-        #1 $stop ;
+        $fatal(1,"\nError: TDP_RAM36K instance %m has parameter WRITE_WIDTH_B set to %d.  Valid values are 1, 2, 4, 9, 18, 36\n", WRITE_WIDTH_B);
       end
     endcase
     case(READ_WIDTH_B)
@@ -524,8 +521,7 @@ module TDP_RAM36K #(
       18 ,
       36: begin end
       default: begin
-        $display("\nError: TDP_RAM36K instance %m has parameter READ_WIDTH_B set to %d.  Valid values are 1, 2, 4, 9, 18, 36\n", READ_WIDTH_B);
-        #1 $stop ;
+        $fatal(1,"\nError: TDP_RAM36K instance %m has parameter READ_WIDTH_B set to %d.  Valid values are 1, 2, 4, 9, 18, 36\n", READ_WIDTH_B);
       end
     endcase
 
diff --git a/models_internal/verilog/inc/DSP19X2.inc.v b/models_internal/verilog/inc/DSP19X2.inc.v
index 5cc069e..ab85e64 100644
--- a/models_internal/verilog/inc/DSP19X2.inc.v
+++ b/models_internal/verilog/inc/DSP19X2.inc.v
@@ -339,15 +339,13 @@
 	always @(ACC_FIR)
 		if (ACC_FIR > 21)
 		begin
-			$display("WARNING: DSP19x2 instance %m ACC_FIR input is %d which is greater than 21 which serves no function", ACC_FIR);
-			#1 $finish ;
+			$fatal(1,"WARNING: DSP19x2 instance %m ACC_FIR input is %d which is greater than 21 which serves no function", ACC_FIR);
 		end
 	// If SHIFT_RIGHT is greater than 31, result is invalid
 	always @(SHIFT_RIGHT)
 		if (SHIFT_RIGHT > 31)
 		begin
-			$display("WARNING: DSP19x2 instance %m SHIFT_RIGHT input is %d which is greater than 31 which serves no function", SHIFT_RIGHT);
-			#1 $finish ;
+			$fatal(1,"WARNING: DSP19x2 instance %m SHIFT_RIGHT input is %d which is greater than 31 which serves no function", SHIFT_RIGHT);
 		end
 	
 	always@(*) 
@@ -355,7 +353,7 @@
 		case(DSP_MODE)
 			"MULTIPLY_ACCUMULATE": begin  
 				if(FEEDBACK>1)
-					$display("\nWARNING: DSP19x2 instance %m has parameter DSP_MODE set to %s and FEEDBACK set to %0d. Valid values of FEEDBACK for this mode are 0,1 \n", DSP_MODE,FEEDBACK);
+					$fatal(1,"\nWARNING: DSP19x2 instance %m has parameter DSP_MODE set to %s and FEEDBACK set to %0d. Valid values of FEEDBACK for this mode are 0,1 \n", DSP_MODE,FEEDBACK);
 			end
 		endcase
 		
diff --git a/models_internal/verilog/inc/DSP38.inc.v b/models_internal/verilog/inc/DSP38.inc.v
index 30e9033..326e90f 100644
--- a/models_internal/verilog/inc/DSP38.inc.v
+++ b/models_internal/verilog/inc/DSP38.inc.v
@@ -263,14 +263,14 @@
 	// If ACC_FIR is greater than 43, result is invalid
 	always @(ACC_FIR)
 		if (ACC_FIR > 43)
-			$display("WARNING: DSP38 instance %m ACC_FIR input is %d which is greater than 43 which serves no function", ACC_FIR);
+			$fatal(1,"\nWARNING: DSP38 instance %m ACC_FIR input is %d which is greater than 43 which serves no function", ACC_FIR);
 
 	always@(*) 
 	begin
 		case(DSP_MODE)
 			"MULTIPLY_ACCUMULATE": begin  
 				if(FEEDBACK>1)
-					$display("\nWARNING: DSP38 instance %m has parameter DSP_MODE set to %s and FEEDBACK set to %0d. Valid values of FEEDBACK for this mode are 0,1 \n", DSP_MODE,FEEDBACK);
+					$fatal(1,"\nWARNING: DSP38 instance %m has parameter DSP_MODE set to %s and FEEDBACK set to %0d. Valid values of FEEDBACK for this mode are 0,1 \n", DSP_MODE,FEEDBACK);
 			end
 		endcase
 		
diff --git a/models_internal/verilog/inc/I_FAB.inc.v b/models_internal/verilog/inc/I_FAB.inc.v
new file mode 100644
index 0000000..127b166
--- /dev/null
+++ b/models_internal/verilog/inc/I_FAB.inc.v
@@ -0,0 +1,3 @@
+
+assign O = I ;
+
diff --git a/models_internal/verilog/inc/I_FAB.pro.v b/models_internal/verilog/inc/I_FAB.pro.v
new file mode 100644
index 0000000..e69de29
diff --git a/models_internal/verilog/inc/O_FAB.inc.v b/models_internal/verilog/inc/O_FAB.inc.v
new file mode 100644
index 0000000..ad0a91b
--- /dev/null
+++ b/models_internal/verilog/inc/O_FAB.inc.v
@@ -0,0 +1,2 @@
+
+assign O = I ;
diff --git a/models_internal/verilog/inc/O_FAB.pro.v b/models_internal/verilog/inc/O_FAB.pro.v
new file mode 100644
index 0000000..e69de29
diff --git a/models_internal/verilog/inc/PLL.inc.v b/models_internal/verilog/inc/PLL.inc.v
index 8f1bed2..59897d4 100644
--- a/models_internal/verilog/inc/PLL.inc.v
+++ b/models_internal/verilog/inc/PLL.inc.v
@@ -134,12 +134,10 @@ localparam      FAST_LOCK      = 0; // Reduce lock time
 	always @ (posedge CLK_IN) begin
 		if(pllstart_ff2)begin
 			if (ref_period<VCO_MIN_PERIOD) begin
-				$display("\nError at time %t: PLL instance %m REF clock period %0d fs violates minimum period.\nMust be greater than %0d fs.\n", $realtime, ref_period, VCO_MIN_PERIOD);
-				$stop;
+				$fatal(1,"\nError at time %t: PLL instance %m REF clock period %0d fs violates minimum period.\nMust be greater than %0d fs.\n", $realtime, ref_period, VCO_MIN_PERIOD);
 			end
 			else if (ref_period>VCO_MAX_PERIOD) begin
-				$display("\nError at time %t: PLL instance %m REF clock period %0d fs violates maximum period.\nMust be less than %0d fs.\n", $realtime, ref_period, VCO_MAX_PERIOD);
-				$stop;
+				$fatal(1,"\nError at time %t: PLL instance %m REF clock period %0d fs violates maximum period.\nMust be less than %0d fs.\n", $realtime, ref_period, VCO_MAX_PERIOD);
 			end
 		end
 	end
@@ -156,12 +154,10 @@ localparam      FAST_LOCK      = 0; // Reduce lock time
 	always @ (posedge FAST_CLK) begin
 		if(vcostart_ff) begin
 			if (vco_period<VCO_MIN_PERIOD) begin
-				$display("\nError at time %t: PLL instance %m VCO clock period %0d fs violates minimum period.\nMust be greater than %0d fs.\nTry increasing PLL_DIV or decreasing PLL_MULT values.\n", $realtime, vco_period, VCO_MIN_PERIOD);
-				$stop;
+				$fatal(1,"\nError at time %t: PLL instance %m VCO clock period %0d fs violates minimum period.\nMust be greater than %0d fs.\nTry increasing PLL_DIV or decreasing PLL_MULT values.\n", $realtime, vco_period, VCO_MIN_PERIOD);
 			end
 			else if (vco_period>VCO_MAX_PERIOD) begin
-				$display("\nError at time %t: PLL instance %m VCO clock period %0d fs violates maximum period.\nMust be less than %0d fs.\nTry increasing PLL_MULT or decreasing PLL_DIV values.\n", $realtime, vco_period, VCO_MAX_PERIOD);
-				$stop;
+				$fatal(1,"\nError at time %t: PLL instance %m VCO clock period %0d fs violates maximum period.\nMust be less than %0d fs.\nTry increasing PLL_MULT or decreasing PLL_DIV values.\n", $realtime, vco_period, VCO_MAX_PERIOD);
 			end
 		end
 	end
@@ -172,19 +168,16 @@ localparam      FAST_LOCK      = 0; // Reduce lock time
 	always @ (posedge CLK_IN, posedge PLL_EN) begin
 		if(PLL_EN)begin
 			if(PLL_POST_DIV0==0)begin
-				$display("Error at time %t: \n \t PLL instance %m, PLL_POST_DIV0 is equal to zero.\n \t Must be greater than 0", $realtime);
-            $stop;
+				$fatal(1,"Error at time %t: \n \t PLL instance %m, PLL_POST_DIV0 is equal to zero.\n \t Must be greater than 0", $realtime);
 			end
 
 			else if(PLL_POST_DIV1==0)begin
-				$display("Error at time %t: \n \t PLL instance %m, PLL_POST_DIV1 is equal to zero.\n \t Must be greater than 0", $realtime);
-				$stop;
+				$fatal(1,"Error at time %t: \n \t PLL instance %m, PLL_POST_DIV1 is equal to zero.\n \t Must be greater than 0", $realtime);
 			end
 
 
 			else if(PLL_POST_DIV1>PLL_POST_DIV0) begin
-				$display("Error at time %t: PLL_POST_DIV1 > PLL_POST_DIV0\n", $realtime);
-				$stop;
+				$fatal(1,"Error at time %t: PLL_POST_DIV1 > PLL_POST_DIV0\n", $realtime);
 			end
 		end
 	end
diff --git a/models_internal/verilog/tb/I_FAB_tb.v b/models_internal/verilog/tb/I_FAB_tb.v
new file mode 100644
index 0000000..f45f083
--- /dev/null
+++ b/models_internal/verilog/tb/I_FAB_tb.v
@@ -0,0 +1,43 @@
+
+module I_FAB_tb;
+
+  // Parameters
+
+  //Ports
+  reg  I;
+  wire  O;
+  int error;
+
+  I_FAB  I_FAB_inst (
+    .I(I),
+    .O(O)
+  );
+
+  initial 
+  begin
+    I = 0;
+    error = 0;
+    #3;
+    I = 1;
+    for(int i=0;i<=63;i++)
+	begin
+        #3;
+		I = $urandom;
+        #1;
+		if(O!==I)
+            error++;
+	end
+
+    if(error===0)
+        $display("I_FAB TEST PASSED");
+    else
+        $error("I_FAB TEST FAILED");
+            
+  end
+  initial 
+  begin
+      $dumpfile("waves.vcd");
+      $dumpvars;
+  end
+
+endmodule
\ No newline at end of file
diff --git a/models_internal/verilog/tb/O_FAB_tb.v b/models_internal/verilog/tb/O_FAB_tb.v
new file mode 100644
index 0000000..eded581
--- /dev/null
+++ b/models_internal/verilog/tb/O_FAB_tb.v
@@ -0,0 +1,43 @@
+
+module O_FAB_tb;
+
+  // Parameters
+
+  //Ports
+  reg  I;
+  wire  O;
+  int error;
+
+  O_FAB  O_FAB_inst (
+    .I(I),
+    .O(O)
+  );
+
+  initial 
+  begin
+    I = 0;
+    error = 0;
+    #3;
+    I = 1;
+    for(int i=0;i<=63;i++)
+	begin
+        #3;
+		I = $urandom;
+        #1;
+		if(O!==I)
+            error++;
+	end
+
+    if(error===0)
+        $display("O_FAB TEST PASSED");
+    else
+        $error("O_FAB TEST FAILED");
+            
+  end
+  initial 
+  begin
+      $dumpfile("waves.vcd");
+      $dumpvars;
+  end
+
+endmodule
\ No newline at end of file
diff --git a/models_internal/verilog_blackbox/cell_sim_blackbox.v b/models_internal/verilog_blackbox/cell_sim_blackbox.v
index 7188897..5844f92 100644
--- a/models_internal/verilog_blackbox/cell_sim_blackbox.v
+++ b/models_internal/verilog_blackbox/cell_sim_blackbox.v
@@ -351,6 +351,20 @@ module I_DELAY #(
 endmodule
 `endcelldefine
 //
+// I_FAB black box model
+// Marker Buffer for periphery to fabric transition
+//
+// Copyright (c) 2024 Rapid Silicon, Inc.  All rights reserved.
+//
+`celldefine
+(* blackbox *)
+module I_FAB (
+  input logic I,
+  output logic O
+);
+endmodule
+`endcelldefine
+//
 // I_SERDES black box model
 // Input Serial Deserializer
 //
@@ -610,6 +624,20 @@ module O_DELAY #(
 endmodule
 `endcelldefine
 //
+// O_FAB black box model
+// Marker Buffer for fabric to periphery transition
+//
+// Copyright (c) 2024 Rapid Silicon, Inc.  All rights reserved.
+//
+`celldefine
+(* blackbox *)
+module O_FAB (
+  input logic I,
+  output logic O
+);
+endmodule
+`endcelldefine
+//
 // O_SERDES_CLK black box model
 // Output Serializer Clock
 //
@@ -946,7 +974,9 @@ module TDP_RAM18KX2 #(
   input logic WEN_B2,
   input logic REN_A2,
   input logic REN_B2,
+  (* clkbuf_sink *)
   input logic CLK_A2,
+  (* clkbuf_sink *)
   input logic CLK_B2,
   input logic [1:0] BE_A2,
   input logic [1:0] BE_B2,
diff --git a/specs/I_DELAY.yaml b/specs/I_DELAY.yaml
index fd19c7a..fb2ea68 100644
--- a/specs/I_DELAY.yaml
+++ b/specs/I_DELAY.yaml
@@ -89,3 +89,8 @@ parameters:
       default: 0
       range: 0 .. 63
 
+control_signal_map:
+    DLY_LOAD: f2g_rx_dly_ld
+    DLY_ADJ: f2g_rx_dly_adj
+    DLY_INCDEC: f2g_rx_dly_inc
+    DLY_TAP_VALUE: g2f_rx_dly_tap
\ No newline at end of file
diff --git a/specs/I_FAB.yaml b/specs/I_FAB.yaml
new file mode 100644
index 0000000..ad0a342
--- /dev/null
+++ b/specs/I_FAB.yaml
@@ -0,0 +1,56 @@
+# Periphery Primitives Parameters and Properties (P4)
+#
+# This file contains the list of Verilog parameters and SDC properties that are
+# allowed for periphery primitives.
+#
+# See https://rapidsilicon.atlassian.net/wiki/spaces/RS/pages/214368265/Periphery+Primitive+Parameters+and+Properties+Definitions+P4DEF for more details
+#
+# The name needs to match the filename root
+# name: <primitive name>
+# desc: <optional description>
+#
+# ports:
+#   <portname>:
+#       dir: <input, output, inout>
+#       desc: <optional description>
+#   <portname>:
+#       dir: <input, output, inout>
+#       desc: <optional description>
+#
+# # set as Verilog parameter
+# parameters:
+#    <parameter_name>:
+#        desc: <description>
+#        values:
+#          - <enum_name>
+#          - <enum_name>
+#    <parameter_name>:
+#        desc: <description>
+#        values:
+#          - <enum_name>
+#          - <enum_name>  
+#
+# # set in SDC or by synthesis attribute
+# properties:
+#    <property_name>:
+#        desc: <description>
+#        values: 
+#          - <enum_name>
+#          - <enum_name>
+#    <property_name>:
+#        desc: <description>
+#          - <enum_name>
+#          - <enum_name>
+#
+# primitive name should match the filename root.
+name: I_FAB
+desc: Marker Buffer for periphery to fabric transition
+category: core_fabric
+
+ports:
+   I:
+     dir:  input
+     desc: Input
+   O:
+     dir: output
+     desc: Output
\ No newline at end of file
diff --git a/specs/I_SERDES.yaml b/specs/I_SERDES.yaml
index f520e1c..cd4a769 100644
--- a/specs/I_SERDES.yaml
+++ b/specs/I_SERDES.yaml
@@ -106,3 +106,14 @@ parameters:
         - NONE
         - DPA
         - CDR
+
+control_signal_map:
+   RST: f2g_rx_reset_n
+   BITSLIP_ADJ: f2g_rx_bitslip_adj
+   EN: f2g_in_en
+   CLK_IN: f2g_rx_core_clk
+   CLK_OUT: g2f_core_clk
+   Q[WIDTH-1:0]: g2f_rx_in
+   DATA_VALID: g2f_rx_dvalid
+   DPA_LOCK: g2f_rx_dpa_lock
+   DPA_ERROR: g2f_rx_dpa_error
\ No newline at end of file
diff --git a/specs/O_DELAY.yaml b/specs/O_DELAY.yaml
index f7013e5..c8cb109 100644
--- a/specs/O_DELAY.yaml
+++ b/specs/O_DELAY.yaml
@@ -88,3 +88,8 @@ parameters:
       default: 0
       range: 0 .. 63
 
+control_signal_map:
+    DLY_LOAD: f2g_tx_dly_ld
+    DLY_ADJ: f2g_tx_dly_adj
+    DLY_INCDEC: f2g_tx_dly_inc
+    DLY_TAP_VALUE: g2f_tx_dly_tap
diff --git a/specs/O_FAB.yaml b/specs/O_FAB.yaml
new file mode 100644
index 0000000..77db480
--- /dev/null
+++ b/specs/O_FAB.yaml
@@ -0,0 +1,56 @@
+# Periphery Primitives Parameters and Properties (P4)
+#
+# This file contains the list of Verilog parameters and SDC properties that are
+# allowed for periphery primitives.
+#
+# See https://rapidsilicon.atlassian.net/wiki/spaces/RS/pages/214368265/Periphery+Primitive+Parameters+and+Properties+Definitions+P4DEF for more details
+#
+# The name needs to match the filename root
+# name: <primitive name>
+# desc: <optional description>
+#
+# ports:
+#   <portname>:
+#       dir: <input, output, inout>
+#       desc: <optional description>
+#   <portname>:
+#       dir: <input, output, inout>
+#       desc: <optional description>
+#
+# # set as Verilog parameter
+# parameters:
+#    <parameter_name>:
+#        desc: <description>
+#        values:
+#          - <enum_name>
+#          - <enum_name>
+#    <parameter_name>:
+#        desc: <description>
+#        values:
+#          - <enum_name>
+#          - <enum_name>  
+#
+# # set in SDC or by synthesis attribute
+# properties:
+#    <property_name>:
+#        desc: <description>
+#        values: 
+#          - <enum_name>
+#          - <enum_name>
+#    <property_name>:
+#        desc: <description>
+#          - <enum_name>
+#          - <enum_name>
+#
+# primitive name should match the filename root.
+name: O_FAB
+desc: Marker Buffer for fabric to periphery transition
+category: core_fabric
+
+ports:
+   I:
+     dir:  input
+     desc: Input
+   O:
+     dir: output
+     desc: Output
\ No newline at end of file
diff --git a/specs/O_SERDES.yaml b/specs/O_SERDES.yaml
index adbad1e..7444d20 100644
--- a/specs/O_SERDES.yaml
+++ b/specs/O_SERDES.yaml
@@ -96,3 +96,11 @@ parameters:
       type: integer
       default: 4
       range: 3 .. 10
+
+control_signal_map:
+   RST: f2g_tx_reset_n
+   DATA_VALID: f2g_tx_dvalid
+   CLK_IN: f2g_tx_core_clk
+   OE_IN: f2g_tx_oe
+   OE_OUT: g2i_tx_oe
+   Q: g2i_tx_out
\ No newline at end of file
diff --git a/specs/O_SERDES_CLK.yaml b/specs/O_SERDES_CLK.yaml
index 19ca9d8..a195b98 100644
--- a/specs/O_SERDES_CLK.yaml
+++ b/specs/O_SERDES_CLK.yaml
@@ -80,3 +80,7 @@ parameters:
         - 90
         - 180
         - 270
+
+control_signal_map:
+   CLK_EN: f2g_tx_clk_en
+   OUTPUT_CLK: g2i_tx_clk
\ No newline at end of file
diff --git a/specs/TDP_RAM18KX2.yaml b/specs/TDP_RAM18KX2.yaml
index c29c272..34daca4 100644
--- a/specs/TDP_RAM18KX2.yaml
+++ b/specs/TDP_RAM18KX2.yaml
@@ -127,9 +127,11 @@ ports:
    CLK_A2:
      dir: input
      desc: Clock port A, RAM 2
+     bb_attributes: clkbuf_sink
    CLK_B2:
      dir: input
      desc: Clock port B, RAM 2
+     bb_attributes: clkbuf_sink
    BE_A2[1:0]:
      dir: input
      desc: Byte-write enable port A, RAM 2