diff --git a/BizHawk.Emulation.Cores/Computers/Commodore64/MOS/Cia.Registers.cs b/BizHawk.Emulation.Cores/Computers/Commodore64/MOS/Cia.Registers.cs
index 1c55076712..0ba58e1ceb 100644
--- a/BizHawk.Emulation.Cores/Computers/Commodore64/MOS/Cia.Registers.cs
+++ b/BizHawk.Emulation.Cores/Computers/Commodore64/MOS/Cia.Registers.cs
@@ -1,4 +1,7 @@
-namespace BizHawk.Emulation.Cores.Computers.Commodore64.MOS
+using BizHawk.Common.NumberExtensions;
+using System;
+
+namespace BizHawk.Emulation.Cores.Computers.Commodore64.MOS
 {
 	public sealed partial class Cia
 	{
@@ -154,7 +157,7 @@
 					break;
 				case 0xC:
 					WriteRegister(addr, val);
-					TriggerInterrupt(8);
+					// TriggerInterrupt(8); 				
 					break;
 				case 0xD:
 					if ((val & 0x80) != 0)
diff --git a/BizHawk.Emulation.Cores/Computers/Commodore64/MOS/Cia.cs b/BizHawk.Emulation.Cores/Computers/Commodore64/MOS/Cia.cs
index ad74ed207b..dccf7bab2f 100644
--- a/BizHawk.Emulation.Cores/Computers/Commodore64/MOS/Cia.cs
+++ b/BizHawk.Emulation.Cores/Computers/Commodore64/MOS/Cia.cs
@@ -15,6 +15,12 @@ namespace BizHawk.Emulation.Cores.Computers.Commodore64.MOS
 				http://frodo.cebix.net/
 		*/
 
+
+		// operation of the interrupt at the serial data port occurs in 2 instances:
+		// 1. Being in output mode and having a complete transfer as defined by clocking of timer A
+		// 2. Being in input mode and receiving 8 clocks from the /CNT pin
+		// This is TODO
+
 		private enum TimerState
 		{
 			Stop = 0,