diff --git a/VHDL/AddressDecoder_Test.vhd b/VHDL/AddressDecoder_Test.vhd
index 1c1e970..9e0738b 100644
--- a/VHDL/AddressDecoder_Test.vhd
+++ b/VHDL/AddressDecoder_Test.vhd
@@ -138,9 +138,16 @@ BEGIN
       A <= "0000";  -- must become "000"
       wait until rising_edge(PHI0);
       NDEV_SEL <= '0';
-      wait until falling_edge(PHI0);
+      wait until falling_edge(PHI0);
+      assert (B="000") report "Address error" severity error;
+      assert (NG='0') report "NG error" severity error;
+      assert (NOE='1') report "NOE error" severity error;
+      assert (NWE='1') report "NWE error" severity error;
       NDEV_SEL <= '1';
       wait until rising_edge(PHI0);
+      assert (NG='1') report "NG error" severity error;
+      assert (NOE='1') report "NOE error" severity error;
+      assert (NWE='1') report "NWE error" severity error;
 
       -- C0nX access, write
       -- NG must be '0"
@@ -150,7 +157,11 @@ BEGIN
       A <= "0000";  -- must become "000"
       wait until rising_edge(PHI0);
       NDEV_SEL <= '0';
-      wait until falling_edge(PHI0);
+      wait until falling_edge(PHI0);
+      assert (B="000") report "Address error" severity error;
+      assert (NG='0') report "NG error" severity error;
+      assert (NOE='1') report "NOE error" severity error;
+      assert (NWE='1') report "NWE error" severity error;
       NDEV_SEL <= '1';
       wait until rising_edge(PHI0);
       
@@ -162,7 +173,11 @@ BEGIN
       A <= "0100";  -- must become "000"     
       wait until rising_edge(PHI0);
       NIO_SEL <= '0';
-      wait until falling_edge(PHI0);
+      wait until falling_edge(PHI0);
+      assert (B="000") report "Address error" severity error;
+      assert (NG='0') report "NG error" severity error;
+      assert (NOE='0') report "NOE error" severity error;
+      assert (NWE='1') report "NWE error" severity error;
       NIO_SEL <= '1';
       wait until rising_edge(PHI0);
 
@@ -174,7 +189,11 @@ BEGIN
       A <= "0100";  -- must become "000"     
       wait until rising_edge(PHI0);
       NIO_SEL <= '0';
-      wait until falling_edge(PHI0);
+      wait until falling_edge(PHI0);
+      assert (B="000") report "Address error" severity error;
+      assert (NG='0') report "NG error" severity error;
+      assert (NOE='1') report "NOE error" severity error;
+      assert (NWE='0') report "NWE error" severity error;
       NIO_SEL <= '1';
       wait until rising_edge(PHI0);
 
@@ -187,7 +206,11 @@ BEGIN
       A <= "0100";  -- must become "000"     
       wait until rising_edge(PHI0);
       NIO_SEL <= '0';
-      wait until falling_edge(PHI0);
+      wait until falling_edge(PHI0);
+      assert (B="000") report "Address error" severity error;
+      assert (NG='0') report "NG error" severity error;
+      assert (NOE='1') report "NOE error" severity error;
+      assert (NWE='1') report "NWE error" severity error;
       NIO_SEL <= '1';
       wait until rising_edge(PHI0);
       
@@ -200,7 +223,11 @@ BEGIN
       A <= "1000";  -- must become "001"      
       wait until rising_edge(PHI0);
       NIO_STB <= '0';
-      wait until falling_edge(PHI0);
+      wait until falling_edge(PHI0);
+      assert (B="001") report "Address error" severity error;
+      assert (NG='0') report "NG error" severity error;
+      assert (NOE='0') report "NOE error" severity error;
+      assert (NWE='1') report "NWE error" severity error;
       NIO_STB <= '1';
       wait until rising_edge(PHI0);
       
@@ -211,7 +238,10 @@ BEGIN
       RNW <= '0';
       wait until rising_edge(PHI0);
       NIO_STB <= '0';
-      wait until falling_edge(PHI0);
+      wait until falling_edge(PHI0);
+      assert (NG='0') report "NG error" severity error;
+      assert (NOE='1') report "NOE error" severity error;
+      assert (NWE='0') report "NWE error" severity error;
       NIO_STB <= '1';
       wait until rising_edge(PHI0);
       
@@ -223,7 +253,11 @@ BEGIN
       A <= "1001";  -- must become "010"      
       wait until rising_edge(PHI0);
       NIO_STB <= '0';
-      wait until falling_edge(PHI0);
+      wait until falling_edge(PHI0);
+      assert (B="010") report "Address error" severity error;
+      assert (NG='0') report "NG error" severity error;
+      assert (NOE='0') report "NOE error" severity error;
+      assert (NWE='1') report "NWE error" severity error;
       NIO_STB <= '1';
       wait until rising_edge(PHI0);
       
@@ -234,7 +268,10 @@ BEGIN
       RNW <= '0';     
       wait until rising_edge(PHI0);
       NIO_STB <= '0';
-      wait until falling_edge(PHI0);
+      wait until falling_edge(PHI0);
+      assert (NG='0') report "NG error" severity error;
+      assert (NOE='1') report "NOE error" severity error;
+      assert (NWE='0') report "NWE error" severity error;
       NIO_STB <= '1';
       wait until rising_edge(PHI0);
       
@@ -246,7 +283,11 @@ BEGIN
       A <= "0101";  -- must become "000"      
       wait until rising_edge(PHI0);
       NDEV_SEL <= '0';
-      wait until falling_edge(PHI0);
+      wait until falling_edge(PHI0);
+      assert (B="000") report "Address error" severity error;
+      assert (NG='0') report "NG error" severity error;
+      assert (NOE='1') report "NOE error" severity error;
+      assert (NWE='1') report "NWE error" severity error;
       NDEV_SEL <= '1';
       wait until rising_edge(PHI0);
       
@@ -257,7 +298,11 @@ BEGIN
       A <= "1111";  -- must become "111"      
       wait until rising_edge(PHI0);
       NIO_STB <= '0';
-      wait until falling_edge(PHI0);
+      wait until falling_edge(PHI0);
+      assert (B="111") report "Address error" severity error;
+      assert (NG='1') report "NG error" severity error;
+      assert (NOE='1') report "NOE error" severity error;
+      assert (NWE='1') report "NWE error" severity error;
       NIO_STB <= '1';
       wait until rising_edge(PHI0);
       
@@ -268,7 +313,11 @@ BEGIN
       A <= "1000"; -- must become "001"      
       wait until rising_edge(PHI0);
       NIO_STB <= '0';
-      wait until falling_edge(PHI0);
+      wait until falling_edge(PHI0);
+      assert (B="001") report "Address error" severity error;
+      assert (NG='1') report "NG error" severity error;
+      assert (NOE='1') report "NOE error" severity error;
+      assert (NWE='1') report "NWE error" severity error;
       NIO_STB <= '1';
       wait until rising_edge(PHI0);
 
@@ -280,7 +329,11 @@ BEGIN
       A <= "1000"; -- must become "001"      
       wait until rising_edge(PHI0);
       NIO_STB <= '0';
-      wait until falling_edge(PHI0);
+      wait until falling_edge(PHI0);
+      assert (B="001") report "Address error" severity error;
+      assert (NG='1') report "NG error" severity error;
+      assert (NOE='1') report "NOE error" severity error;
+      assert (NWE='1') report "NWE error" severity error;
       NIO_STB <= '1';
       wait until rising_edge(PHI0);