diff --git a/MC6809/test/Board.cpp b/MC6809/test/Board.cpp
index cbd105c..230a7de 100644
--- a/MC6809/test/Board.cpp
+++ b/MC6809/test/Board.cpp
@@ -33,6 +33,10 @@ void Board::initialise() {
 	CPU().reset();
 
 	ACIA().powerOn();
+	ACIA().RW() = EightBit::Chip::PinLevel::Low;	// Write
+	ACIA().RS() = EightBit::Chip::PinLevel::Low;	// Registers
+	EightBit::Processor::setFlag(ACIA().DATA(), EightBit::mc6850::CR0 | EightBit::mc6850::CR1);
+	ACIA().step(1);	// Get the reset out of the way...
 }
 
 void Board::Cpu_ExecutingInstruction_Debug(EightBit::mc6809&) {
@@ -66,16 +70,15 @@ EightBit::MemoryMapping Board::mapping(uint16_t address) {
 }
 
 void Board::Bus_WritingByte_Acia(EightBit::EventArgs&) {
-	ACIA().RW() = EightBit::Chip::Low;
-	updateAciaPins();
+	updateAciaPins(EightBit::Chip::Low);
 }
 
 void Board::Bus_ReadingByte_Acia(EightBit::EventArgs&) {
-	ACIA().RW() = EightBit::Chip::High;
-	updateAciaPins();
+	updateAciaPins(EightBit::Chip::High);
 }
 
-void Board::updateAciaPins() {
+void Board::updateAciaPins(const EightBit::Chip::PinLevel rw) {
+	ACIA().RW() = rw;
 	ACIA().DATA() = DATA();
 	ACIA().RS() = ADDRESS().word & EightBit::Chip::Bit0 ? EightBit::Chip::PinLevel::High : EightBit::Chip::PinLevel::Low;
 	ACIA().CS0() = ADDRESS().word & EightBit::Chip::Bit15 ? EightBit::Chip::PinLevel::High : EightBit::Chip::PinLevel::Low;
diff --git a/MC6809/test/Board.h b/MC6809/test/Board.h
index c21c60f..f93e10a 100644
--- a/MC6809/test/Board.h
+++ b/MC6809/test/Board.h
@@ -48,8 +48,8 @@ private:
 
 	void pollKeyboard();
 
-	void Cpu_ExecutingInstruction_Debug(EightBit::mc6809& cpu);
-	void Cpu_ExecutedInstruction_Debug(EightBit::mc6809& cpu);
+	void Cpu_ExecutingInstruction_Debug(EightBit::mc6809&);
+	void Cpu_ExecutedInstruction_Debug(EightBit::mc6809&);
 
 	void Cpu_ExecutedInstruction_die(EightBit::mc6809&);
 
@@ -60,5 +60,5 @@ private:
 
 	void Cpu_ExecutedInstruction_Acia(EightBit::mc6809&);
 
-	void updateAciaPins();
+	void updateAciaPins(EightBit::Chip::PinLevel rw);
 };
diff --git a/MC6809/test/test.cpp b/MC6809/test/test.cpp
index a2ef3e3..13bf177 100644
--- a/MC6809/test/test.cpp
+++ b/MC6809/test/test.cpp
@@ -11,7 +11,7 @@ int main(int argc, char* argv[]) {
 	Configuration configuration;
 
 #ifdef _DEBUG
-	//configuration.setDebugMode(true);
+	configuration.setDebugMode(true);
 #endif
 	//configuration.setDebugMode(true);
 
diff --git a/MC6850/inc/MC6850.h b/MC6850/inc/MC6850.h
index dce918e..73c0442 100644
--- a/MC6850/inc/MC6850.h
+++ b/MC6850/inc/MC6850.h
@@ -94,13 +94,25 @@ namespace EightBit {
 
 		void step(int cycles);
 
+		// External access to RDR
+		void fillRDR(uint8_t data);
+
 	private:
+		uint8_t& TDR() { return m_TDR; }	// Transmit data register;
+		uint8_t& RDR() { return m_RDR; }	// Receive data register;
+
+		uint8_t& status() { return m_status; }
+
 		bool selected();
 
 		void reset();
 
 		void step();
 
+		uint8_t drainRDR();				// External (hacked!) access to RDR
+		void fillTDR(uint8_t data);		// External (hacked!) access to TDR
+		uint8_t drainTDR();				// External (hacked!) access to TDR
+
 		PinLevel m_RXDATA;
 		PinLevel m_TXDATA;
 
@@ -130,6 +142,12 @@ namespace EightBit {
 		int m_receiveControl;
 
 		// Status registers
-		bool m_RDRF;
+		uint8_t m_status;
+
+		// Data registers
+		uint8_t m_TDR;
+		uint8_t m_RDR;
+
+		bool m_firstMasterReset = false;
 	};
 }
diff --git a/MC6850/src/MC6850.cpp b/MC6850/src/MC6850.cpp
index 262a0f3..ea1a824 100644
Binary files a/MC6850/src/MC6850.cpp and b/MC6850/src/MC6850.cpp differ
diff --git a/inc/Processor.h b/inc/Processor.h
index f136bec..f150d1a 100644
--- a/inc/Processor.h
+++ b/inc/Processor.h
@@ -11,6 +11,17 @@
 namespace EightBit {
 	class Processor : public Chip {
 	public:
+		static void clearFlag(uint8_t& f, const int flag) { f &= ~flag; }
+		static void setFlag(uint8_t& f, const int flag) { f |= flag; }
+
+		static void setFlag(uint8_t& f, const int flag, const int condition) { setFlag(f, flag, !!condition); }
+		static void setFlag(uint8_t& f, const int flag, const uint32_t condition) { setFlag(f, flag, !!condition); }
+		static void setFlag(uint8_t& f, const int flag, const bool condition) { condition ? setFlag(f, flag) : clearFlag(f, flag); }
+
+		static void clearFlag(uint8_t& f, const int flag, const int condition) { clearFlag(f, flag, !!condition); }
+		static void clearFlag(uint8_t& f, const int flag, const uint32_t condition) { clearFlag(f, flag, !!condition); }
+		static void clearFlag(uint8_t& f, const int flag, const bool condition) { setFlag(f, flag, !condition); }
+
 		// b: number of bits representing the number in x
 		// x: sign extend this b-bit number to r
 		static int8_t signExtend(int b, uint8_t x);
@@ -36,17 +47,6 @@ namespace EightBit {
 		virtual register16_t peekWord(register16_t address) = 0;
 
 	protected:
-		static void clearFlag(uint8_t& f, const int flag) { f &= ~flag; }
-		static void setFlag(uint8_t& f, const int flag) { f |= flag; }
-
-		static void setFlag(uint8_t& f, const int flag, const int condition) { setFlag(f, flag, !!condition); }
-		static void setFlag(uint8_t& f, const int flag, const uint32_t condition) { setFlag(f, flag, !!condition); }
-		static void setFlag(uint8_t& f, const int flag, const bool condition) { condition ? setFlag(f, flag) : clearFlag(f, flag); }
-
-		static void clearFlag(uint8_t& f, const int flag, const int condition) { clearFlag(f, flag, !!condition); }
-		static void clearFlag(uint8_t& f, const int flag, const uint32_t condition) { clearFlag(f, flag, !!condition); }
-		static void clearFlag(uint8_t& f, const int flag, const bool condition) { setFlag(f, flag, !condition); }
-
 		Processor(Bus& memory);
 		virtual ~Processor() = default;