diff --git a/BizHawk.Emulation/Consoles/Atari/2600/Atari2600.Core.cs b/BizHawk.Emulation/Consoles/Atari/2600/Atari2600.Core.cs
index 2aa061e095..131a0c556d 100644
--- a/BizHawk.Emulation/Consoles/Atari/2600/Atari2600.Core.cs
+++ b/BizHawk.Emulation/Consoles/Atari/2600/Atari2600.Core.cs
@@ -96,7 +96,7 @@ namespace BizHawk
 		{
 			byte temp = mapper.ReadMemory((ushort)(addr&0x1FFF));
 
-			if (CoreInputComm.MemoryCallbackSystem.ReadCallback != null)
+			if (CoreInputComm.MemoryCallbackSystem.HasRead)
 			{
 				CoreInputComm.MemoryCallbackSystem.TriggerRead(addr);
 			}
@@ -108,9 +108,9 @@ namespace BizHawk
 		{
 			mapper.WriteMemory((ushort)(addr & 0x1FFF), value);
 
-			if (CoreInputComm.MemoryCallbackSystem.WriteCallback != null)
+			if (CoreInputComm.MemoryCallbackSystem.HasWrite)
 			{
-				CoreInputComm.MemoryCallbackSystem.WriteCallback();
+				CoreInputComm.MemoryCallbackSystem.TriggerWrite(addr);
 			}
 		}
 
diff --git a/BizHawk.Emulation/Consoles/Calculator/TI83.cs b/BizHawk.Emulation/Consoles/Calculator/TI83.cs
index a0ddd06c82..31935d34fa 100644
--- a/BizHawk.Emulation/Consoles/Calculator/TI83.cs
+++ b/BizHawk.Emulation/Consoles/Calculator/TI83.cs
@@ -39,7 +39,7 @@ namespace BizHawk.Emulation.Consoles.Calculator
 				ret = rom[romPage * 0x4000 + addr - 0x4000]; //other rom page
 			else ret = ram[addr - 0x8000];
 
-			if (CoreInputComm.MemoryCallbackSystem.ReadCallback != null)
+			if (CoreInputComm.MemoryCallbackSystem.HasRead)
 			{
 				CoreInputComm.MemoryCallbackSystem.TriggerRead(addr);
 			}
@@ -55,9 +55,9 @@ namespace BizHawk.Emulation.Consoles.Calculator
 				return; //other rom page
 			else ram[addr - 0x8000] = value;
 
-			if (CoreInputComm.MemoryCallbackSystem.WriteCallback != null)
+			if (CoreInputComm.MemoryCallbackSystem.HasWrite)
 			{
-				CoreInputComm.MemoryCallbackSystem.WriteCallback();
+				CoreInputComm.MemoryCallbackSystem.TriggerWrite(addr);
 			}
 		}
 
diff --git a/BizHawk.Emulation/Consoles/Coleco/ColecoVision.Core.cs b/BizHawk.Emulation/Consoles/Coleco/ColecoVision.Core.cs
index edb9b6f60c..69f94d7565 100644
--- a/BizHawk.Emulation/Consoles/Coleco/ColecoVision.Core.cs
+++ b/BizHawk.Emulation/Consoles/Coleco/ColecoVision.Core.cs
@@ -40,7 +40,7 @@ namespace BizHawk.Emulation.Consoles.Coleco
 				ret = 0xFF;
 			}
 
-			if (CoreInputComm.MemoryCallbackSystem.ReadCallback != null)
+			if (CoreInputComm.MemoryCallbackSystem.HasRead)
 			{
 				CoreInputComm.MemoryCallbackSystem.TriggerRead(addr);
 			}
@@ -55,9 +55,9 @@ namespace BizHawk.Emulation.Consoles.Coleco
 				ram[addr] = value;
 			}
 
-			if (CoreInputComm.MemoryCallbackSystem.WriteCallback != null)
+			if (CoreInputComm.MemoryCallbackSystem.HasWrite)
 			{
-				CoreInputComm.MemoryCallbackSystem.WriteCallback();
+				CoreInputComm.MemoryCallbackSystem.TriggerWrite(addr);
 			}
 		}
 
diff --git a/BizHawk.Emulation/Consoles/Intellivision/MemoryMap.cs b/BizHawk.Emulation/Consoles/Intellivision/MemoryMap.cs
index ae191f4565..4686b3fc97 100644
--- a/BizHawk.Emulation/Consoles/Intellivision/MemoryMap.cs
+++ b/BizHawk.Emulation/Consoles/Intellivision/MemoryMap.cs
@@ -115,7 +115,7 @@ namespace BizHawk.Emulation.Consoles.Intellivision
 						break;
 			}
 
-			if (CoreInputComm.MemoryCallbackSystem.ReadCallback != null)
+			if (CoreInputComm.MemoryCallbackSystem.HasRead)
 			{
 				CoreInputComm.MemoryCallbackSystem.TriggerRead(addr);
 			}
@@ -286,9 +286,9 @@ namespace BizHawk.Emulation.Consoles.Intellivision
 					}
 			}
 
-			if (CoreInputComm.MemoryCallbackSystem.WriteCallback != null)
+			if (CoreInputComm.MemoryCallbackSystem.HasWrite)
 			{
-				CoreInputComm.MemoryCallbackSystem.WriteCallback();
+				CoreInputComm.MemoryCallbackSystem.TriggerWrite(addr);
 			}
 
 			return (cart || stic || psg);
diff --git a/BizHawk.Emulation/Consoles/Nintendo/NES/Core.cs b/BizHawk.Emulation/Consoles/Nintendo/NES/Core.cs
index 999a402920..4452bd2f22 100644
--- a/BizHawk.Emulation/Consoles/Nintendo/NES/Core.cs
+++ b/BizHawk.Emulation/Consoles/Nintendo/NES/Core.cs
@@ -369,7 +369,7 @@ namespace BizHawk.Emulation.Consoles.Nintendo
 				ret = sysbus_watch[addr].ApplyGameGenie(ret);
 			}
 
-			if (CoreInputComm.MemoryCallbackSystem.ReadCallback != null)
+			if (CoreInputComm.MemoryCallbackSystem.HasRead)
 			{
 				CoreInputComm.MemoryCallbackSystem.TriggerRead(addr);
 			}
@@ -426,9 +426,9 @@ namespace BizHawk.Emulation.Consoles.Nintendo
 				board.WritePRG(addr - 0x8000, value);
 			}
 
-			if (CoreInputComm.MemoryCallbackSystem.WriteCallback != null)
+			if (CoreInputComm.MemoryCallbackSystem.HasWrite)
 			{
-				CoreInputComm.MemoryCallbackSystem.WriteCallback();
+				CoreInputComm.MemoryCallbackSystem.TriggerWrite(addr);
 			}
 		}
 
diff --git a/BizHawk.Emulation/Consoles/PC Engine/MemoryMap.cs b/BizHawk.Emulation/Consoles/PC Engine/MemoryMap.cs
index c0a661674e..dd6a9a60c2 100644
--- a/BizHawk.Emulation/Consoles/PC Engine/MemoryMap.cs	
+++ b/BizHawk.Emulation/Consoles/PC Engine/MemoryMap.cs	
@@ -33,7 +33,7 @@
 				return 0xFF;
 			}
 
-			if (CoreInputComm.MemoryCallbackSystem.ReadCallback != null)
+			if (CoreInputComm.MemoryCallbackSystem.HasRead)
 			{
 				CoreInputComm.MemoryCallbackSystem.TriggerRead(addr);
 			}
@@ -74,9 +74,9 @@
 			else
 				Log.Error("MEM", "UNHANDLED WRITE: {0:X6}:{1:X2}", addr, value);
 
-			if (CoreInputComm.MemoryCallbackSystem.WriteCallback != null)
+			if (CoreInputComm.MemoryCallbackSystem.HasWrite)
 			{
-				CoreInputComm.MemoryCallbackSystem.WriteCallback();
+				CoreInputComm.MemoryCallbackSystem.TriggerWrite(addr);
 			}
 		}
 	}
diff --git a/BizHawk.Emulation/Consoles/Sega/SMS/MemoryMap.Sega.cs b/BizHawk.Emulation/Consoles/Sega/SMS/MemoryMap.Sega.cs
index 971ad06250..6892b01377 100644
--- a/BizHawk.Emulation/Consoles/Sega/SMS/MemoryMap.Sega.cs
+++ b/BizHawk.Emulation/Consoles/Sega/SMS/MemoryMap.Sega.cs
@@ -43,7 +43,7 @@
 				ret = SystemRam[address & RamSizeMask];
 			}
 
-			if (CoreInputComm.MemoryCallbackSystem.ReadCallback != null)
+			if (CoreInputComm.MemoryCallbackSystem.HasRead)
 			{
 				CoreInputComm.MemoryCallbackSystem.TriggerRead(address);
 			}
@@ -81,9 +81,9 @@
 				return;
 			}
 
-			if (CoreInputComm.MemoryCallbackSystem.WriteCallback != null)
+			if (CoreInputComm.MemoryCallbackSystem.HasWrite)
 			{
-				CoreInputComm.MemoryCallbackSystem.WriteCallback();
+				CoreInputComm.MemoryCallbackSystem.TriggerWrite(address);
 			}
 		}
 
diff --git a/BizHawk.Emulation/Interfaces/CoreComms.cs b/BizHawk.Emulation/Interfaces/CoreComms.cs
index fc0b6d58ac..2bbde2a4aa 100644
--- a/BizHawk.Emulation/Interfaces/CoreComms.cs
+++ b/BizHawk.Emulation/Interfaces/CoreComms.cs
@@ -99,7 +99,19 @@ namespace BizHawk
 	public class MemoryCallbackSystem
 	{
 		public int? ReadAddr = null;
-		public System.Action ReadCallback = null;
+		private System.Action ReadCallback = null;
+		public void SetReadCallback(System.Action func)
+		{
+			ReadCallback = func;
+		}
+
+		public bool HasRead
+		{
+			get
+			{
+				return ReadCallback != null;
+			}
+		}
 
 		public void TriggerRead(int addr)
 		{
@@ -120,7 +132,19 @@ namespace BizHawk
 		}
 
 		public int? WriteAddr = null;
-		public System.Action WriteCallback = null;
+		private System.Action WriteCallback = null;
+		public void SetWriteCallback(System.Action func)
+		{
+			WriteCallback = func;
+		}
+
+		public bool HasWrite
+		{
+			get
+			{
+				return WriteCallback != null;
+			}
+		}
 
 		public void TriggerWrite(int addr)
 		{
diff --git a/BizHawk.MultiClient/LuaImplementation.cs b/BizHawk.MultiClient/LuaImplementation.cs
index b585015464..d4d8265ffc 100644
--- a/BizHawk.MultiClient/LuaImplementation.cs
+++ b/BizHawk.MultiClient/LuaImplementation.cs
@@ -2698,7 +2698,7 @@ namespace BizHawk.MultiClient
 				}
 
 				Global.Emulator.CoreInputComm.MemoryCallbackSystem.ReadAddr = _addr;
-				Global.Emulator.CoreInputComm.MemoryCallbackSystem.ReadCallback = delegate()
+				Global.Emulator.CoreInputComm.MemoryCallbackSystem.SetReadCallback(delegate()
 				{
 					try
 					{
@@ -2710,12 +2710,12 @@ namespace BizHawk.MultiClient
 							"error running function attached by lua function event.onmemoryread" +
 							"\nError message: " + e.Message);
 					}
-				};
+				});
 
 			}
 			else
 			{
-				Global.Emulator.CoreInputComm.MemoryCallbackSystem.ReadCallback = null;
+				Global.Emulator.CoreInputComm.MemoryCallbackSystem.SetReadCallback(null);
 			}
 		}
 
@@ -2736,7 +2736,7 @@ namespace BizHawk.MultiClient
 				}
 
 				Global.Emulator.CoreInputComm.MemoryCallbackSystem.WriteAddr = _addr;
-				Global.Emulator.CoreInputComm.MemoryCallbackSystem.WriteCallback = delegate()
+				Global.Emulator.CoreInputComm.MemoryCallbackSystem.SetWriteCallback(delegate()
 				{
 					try
 					{
@@ -2748,11 +2748,11 @@ namespace BizHawk.MultiClient
 							"error running function attached by lua function event.onmemoryread" +
 							"\nError message: " + e.Message);
 					}
-				};
+				});
 			}
 			else
 			{
-				Global.Emulator.CoreInputComm.MemoryCallbackSystem.WriteCallback = null;
+				Global.Emulator.CoreInputComm.MemoryCallbackSystem.SetWriteCallback(null);
 			}
 		}
 	}