diff --git a/BizHawk.Emulation/Computers/Commodore64/C64.core.cs b/BizHawk.Emulation/Computers/Commodore64/C64.core.cs
index e97ac2bbd8..f1fa692303 100644
--- a/BizHawk.Emulation/Computers/Commodore64/C64.core.cs
+++ b/BizHawk.Emulation/Computers/Commodore64/C64.core.cs
@@ -35,6 +35,9 @@ namespace BizHawk.Emulation.Computers.Commodore64
 		public VicIINew vic;
 		public ChipSignals signal;
 
+		// cpu
+		private bool haltCPU;
+
 		public bool DriveLED
 		{
 			get
@@ -65,7 +68,7 @@ namespace BizHawk.Emulation.Computers.Commodore64
 		{
 			// initalize cpu
 			cpu = new MOS6502X();
-			cpu.ReadMemory = ReadMemory;
+			cpu.ReadMemory = ReadMemoryCPU;
 			cpu.WriteMemory = WriteMemory;
 			cpu.DummyReadMemory = PeekMemory;
 
@@ -150,6 +153,13 @@ namespace BizHawk.Emulation.Computers.Commodore64
 			return mem.Read(addr);
 		}
 
+		private byte ReadMemoryCPU(ushort addr)
+		{
+			if (!signal.CpuAEC)
+				haltCPU = true;
+			return mem.Read(addr);
+		}
+
 		public void WriteMemory(ushort addr, byte value)
 		{
 			mem.Write(addr, value);
diff --git a/BizHawk.Emulation/Computers/Commodore64/C64.cs b/BizHawk.Emulation/Computers/Commodore64/C64.cs
index ba3f219d2b..57eeb66852 100644
--- a/BizHawk.Emulation/Computers/Commodore64/C64.cs
+++ b/BizHawk.Emulation/Computers/Commodore64/C64.cs
@@ -102,10 +102,9 @@ namespace BizHawk.Emulation.Computers.Commodore64
 			// perform the cycle
 			for (int i = 0; i < cyclesPerFrame; i++)
 			{
-				if (signal.CpuAEC)
-				{
+				if (!haltCPU)
 					cpu.ExecuteOne();
-				}
+
 				vic.PerformCycle();
 				cpu.IRQ = signal.CpuIRQ;
 				cpu.NMI = signal.CpuNMI;
@@ -114,8 +113,13 @@ namespace BizHawk.Emulation.Computers.Commodore64
 				cia1.PerformCycle();
 				signal.CiaIRQ1 = cia1.IRQ;
 				sid.PerformCycle();
+
 				if (diskDriveAttached)
 					diskDrive.PerformCycle();
+
+				if (signal.CpuAEC)
+					haltCPU = false;
+
 			}
 
 			_islag = !mem.inputWasRead;
diff --git a/BizHawk.Emulation/Computers/Commodore64/Cia.cs b/BizHawk.Emulation/Computers/Commodore64/Cia.cs
index 5a84ef3385..2f2b69f7a0 100644
--- a/BizHawk.Emulation/Computers/Commodore64/Cia.cs
+++ b/BizHawk.Emulation/Computers/Commodore64/Cia.cs
@@ -475,7 +475,7 @@ namespace BizHawk.Emulation.Computers.Commodore64
 		{
 			int timer = regs.T[index];
 			timer--;
-			if (timer == 0)
+			if (timer < 0)
 			{
 				underflow[index] = true;
 				if (regs.RUNMODE[index])
diff --git a/BizHawk.Emulation/Computers/Commodore64/MemBus.cs b/BizHawk.Emulation/Computers/Commodore64/MemBus.cs
index 0bddda535b..37a2ad0be7 100644
--- a/BizHawk.Emulation/Computers/Commodore64/MemBus.cs
+++ b/BizHawk.Emulation/Computers/Commodore64/MemBus.cs
@@ -101,6 +101,8 @@ namespace BizHawk.Emulation.Computers.Commodore64
 			cia1 = newCia1;
 
 			cpuPort = cpuPortBus.Connect();
+			cpuPort.Latch = 0x00;
+			cpuPort.Direction = 0x1F;
 			cpuPortBus.AttachWriteHook(UpdateLayout);
 			
 			cpuIO = cpuPortBus.Connect();