-Made Executive ROM and Graphics ROM read-only. I still haven't made the memory map accessibility limited by the VBlank Period, but I'm assuming that should come way later.

-Initialized the memory devices with a tentative size that ignores the unofficial ranges.
-Masked addresses to match those sizes (That's my understanding of what the memory map needs to do based on other examples).
-Added the ICart interface.
-Started the Intellicart parser; got far enough to know that the files I'm working with are not Intellicarts. ^_^

BizHawk.Emulation/BizHawk.Emulation.csproj

@@ -114,6 +114,7 @@
     <Compile Include="Consoles\GB\Input.cs" />
     <Compile Include="Consoles\GB\MemoryMap.cs" />
     <Compile Include="Consoles\GB\GB.cs" />
+    <Compile Include="Consoles\Intellivision\Intellicart.cs" />
     <Compile Include="Consoles\Intellivision\Intellivision.cs" />
     <Compile Include="Consoles\Intellivision\MemoryMap.cs" />
     <Compile Include="Consoles\Nintendo\NES\APU.cs" />
@@ -311,6 +312,7 @@
     <Compile Include="Interfaces\Base Implementations\NullController.cs" />
     <Compile Include="Interfaces\Base Implementations\NullEmulator.cs" />
     <Compile Include="Interfaces\CoreComms.cs" />
+    <Compile Include="Interfaces\ICart.cs" />
     <Compile Include="Properties\svnrev.cs" />
     <Compile Include="QuickCollections.cs" />
     <Compile Include="Sound\CDAudio.cs" />

BizHawk.Emulation/Consoles/Intellivision/Intellicart.cs

@@ -0,0 +1,30 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace BizHawk.Emulation.Consoles.Intellivision
+{
+	public sealed partial class Intellivision : ICart
+	{
+		private ushort[] memory = new ushort[65536];
+
+		public void Parse()
+		{
+			// Check to see if the header is valid.
+			if (Rom[0] != 0xA8 || Rom[1] != (0xFF ^ Rom[2]))
+				throw new ArgumentException();
+		}
+
+		public ushort ReadMemory(ushort addr, out bool responded)
+		{
+			responded = false;
+			return 0;
+		}
+
+		public void WriteMemory(ushort addr, ushort value, out bool responded)
+		{
+			responded = false;
+		}
+	}
+}

BizHawk.Emulation/Consoles/Intellivision/Intellivision.cs

@@ -16,6 +16,7 @@ namespace BizHawk.Emulation.Consoles.Intellivision
 		{
 			Rom = rom;
 			Game = game;
+			Parse();
 
 			Cpu = new CP1610();
 			Cpu.ReadMemory = ReadMemory;

BizHawk.Emulation/Consoles/Intellivision/MemoryMap.cs

@@ -7,13 +7,13 @@ namespace BizHawk.Emulation.Consoles.Intellivision
 {
 	public sealed partial class Intellivision
 	{
-		private ushort[] STIC_Registers;
-		private ushort[] Scratchpad_RAM;
-		private ushort[] PSG_Registers;
-		private ushort[] System_RAM;
-		private ushort[] Executive_ROM;
-		private ushort[] Graphics_ROM;
-		private ushort[] Graphics_RAM;
+		private ushort[] STIC_Registers = new ushort[64];
+		private ushort[] Scratchpad_RAM = new ushort[240];
+		private ushort[] PSG_Registers = new ushort[16];
+		private ushort[] System_RAM = new ushort[352];
+		private ushort[] Executive_ROM = new ushort[4096];
+		private ushort[] Graphics_ROM = new ushort[2048];
+		private ushort[] Graphics_RAM = new ushort[512];
 
 		public ushort ReadMemory(ushort addr)
 		{
@@ -21,19 +21,19 @@ namespace BizHawk.Emulation.Consoles.Intellivision
 			{
 				case 0x0000:
 					if (addr >= 0x0100 && addr <= 0x01EF)
-						return Scratchpad_RAM[addr];
+						return Scratchpad_RAM[addr & 0x00EF];
 					if (addr >= 0x01F0 && addr <= 0x01FF)
-						return PSG_Registers[addr];
+						return PSG_Registers[addr & 0x000F];
 					if (addr >= 0x0200 && addr <= 0x035F)
-						return System_RAM[addr];
+						return System_RAM[addr & 0x015F];
 					break;
 				case 0x1000:
-					return Executive_ROM[addr];
+					return Executive_ROM[addr & 0x0FFF];
 				case 0x3000:
 					if (addr >= 0x3000 && addr <= 0x37FF)
-						return Graphics_ROM[addr];
+						return Graphics_ROM[addr & 0x07FF];
 					if (addr >= 0x3800 && addr <= 0x39FF)
-						return Graphics_RAM[addr];
+						return Graphics_RAM[addr & 0x01FF];
 					break;
 			}
 			throw new NotImplementedException();
@@ -46,32 +46,24 @@ namespace BizHawk.Emulation.Consoles.Intellivision
 				case 0x0000:
 					if (addr >= 0x0100 && addr <= 0x01EF)
 					{
-						Scratchpad_RAM[addr] = value;
+						Scratchpad_RAM[addr & 0x00EF] = value;
 						return;
 					}
 					if (addr >= 0x01F0 && addr <= 0x01FF)
 					{
-						PSG_Registers[addr] = value;
+						PSG_Registers[addr & 0x000F] = value;
 						return;
 					}
 					if (addr >= 0x0200 && addr <= 0x035F)
 					{
-						System_RAM[addr] = value;
+						System_RAM[addr & 0x015F] = value;
 						return;
 					}
 					break;
-				case 0x1000:
-					Executive_ROM[addr] = value;
-					return;
 				case 0x3000:
-					if (addr >= 0x3000 && addr <= 0x37FF)
-					{
-						Graphics_ROM[addr] = value;
-						return;
-					}
 					if (addr >= 0x3800 && addr <= 0x39FF)
 					{
-						Graphics_RAM[addr] = value;
+						Graphics_RAM[addr & 0x01FF] = value;
 						return;
 					}
 					break;

BizHawk.Emulation/Interfaces/ICart.cs

@@ -0,0 +1,13 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace BizHawk
+{
+	public interface ICart
+	{
+		ushort ReadMemory(ushort addr, out bool responded);
+		void WriteMemory(ushort addr, ushort value, out bool responded);
+	}
+}