diff --git a/io.cpp b/io.cpp
index b36d605..34518d7 100644
--- a/io.cpp
+++ b/io.cpp
@@ -12,11 +12,6 @@
 #include "hardware.h"
 #include "config.h"
 
-#define ROWS	24
-#define COLS	40
-static unsigned r, c;
-static char screen[ROWS][COLS];
-
 void io::reset() {
 	Display::begin(BG_COLOUR, FG_COLOUR, ORIENT);
 	clear();
@@ -78,7 +73,6 @@ static const uint8_t shiftmap[] PROGMEM = {
 };
 
 void io::down(uint8_t scan) {
-	PIA::write_porta(0);
 	if (isshift(scan))
 		_shift = true;
 }
diff --git a/io.h b/io.h
index e11a40e..d640bd2 100644
--- a/io.h
+++ b/io.h
@@ -6,8 +6,8 @@ public:
 	io(filer &files): Memory::Device(Memory::page_size), files(files) {}
 
 	virtual void reset();
-	virtual void down(uint8_t scan);
-	virtual void up(uint8_t scan);
+	virtual void down(uint8_t);
+	virtual void up(uint8_t);
 
 	virtual void operator=(uint8_t b) { PIA::write(_acc, b); }
 	virtual operator uint8_t() { return PIA::read(_acc); }
@@ -20,13 +20,18 @@ public:
 
 	void load();
 	filer &files;
+
+	static const uint8_t ROWS = 24;
+	static const uint8_t COLS = 40;
+
 private:
 	void display(uint8_t);
 	void draw(char, int, int);
 	void enter(uint8_t);
 
-	bool _shift;
-	bool _loading;
+	bool _shift, _loading;
+	uint8_t r, c;
+	char screen[ROWS][COLS];
 };
 
 #endif
diff --git a/pia.cpp b/pia.cpp
index 2d0b473..6f4eb8e 100644
--- a/pia.cpp
+++ b/pia.cpp
@@ -9,6 +9,14 @@ inline bool c1_low_to_high(uint8_t cr) { return cr & 0x02; }
 
 inline bool c1_high_to_low(uint8_t cr) { return !c1_low_to_high(cr); }
 
+inline bool c2_output(uint8_t cr) { return cr & 0x20; }
+
+inline bool c2_input(uint8_t cr) { return !c2_input(cr); }
+
+inline bool c2_low_to_high(uint8_t cr) { return cr & 0x10; }
+
+inline bool c2_high_to_low(uint8_t cr) { return !c2_low_to_high(cr); }
+
 void PIA::write(Memory::address a, uint8_t b) {
 #if defined(DEBUGGING)
 	Serial.print(millis());
@@ -58,9 +66,13 @@ void PIA::checkpoint(Stream &s) {
 	s.write(porta_cr);
 	s.write(porta);
 	s.write(irq_b1);
+	s.write(irq_b2);
 	s.write(irq_a1);
+	s.write(irq_a2);
 	s.write(cb1);
+	s.write(cb2);
 	s.write(ca1);
+	s.write(ca2);
 }
 
 void PIA::restore(Stream &s) {
@@ -69,9 +81,13 @@ void PIA::restore(Stream &s) {
 	porta_cr = s.read();
 	porta = s.read();
 	irq_b1 = s.read();
+	irq_b2 = s.read();
 	irq_a1 = s.read();
+	irq_a2 = s.read();
 	cb1 = s.read();
+	cb2 = s.read();
 	ca1 = s.read();
+	ca2 = s.read();
 }
 
 void PIA::write_ca1(bool state) {
@@ -85,6 +101,17 @@ void PIA::write_ca1(bool state) {
 	ca1 = state;
 }
 
+void PIA::write_ca2(bool state) {
+
+	if (ca2 == state || !c2_input(porta_cr))
+		return;
+
+	if ((state && c2_low_to_high(porta_cr)) || (!state && c2_high_to_low(porta_cr)))
+		irq_a2 = true;
+
+	ca2 = state;
+}
+
 void PIA::write_cb1(bool state) {
 
 	if (cb1 == state)
@@ -96,14 +123,37 @@ void PIA::write_cb1(bool state) {
 	cb1 = state;
 }
 
+void PIA::write_cb2(bool state) {
+
+	if (cb2 == state || !c2_input(portb_cr))
+		return;
+
+	if ((state && c2_low_to_high(portb_cr)) || (!state && c2_high_to_low(portb_cr)))
+		irq_b2 = true;
+
+	cb2 = state;
+}
+
 uint8_t PIA::read_porta_cr() {
+	byte b = porta_cr;
+
 	if (irq_a1)
-		return porta_cr | IRQ1;
-	return porta_cr;
+		b |= IRQ1;
+
+	if (irq_a2 && c2_input(porta_cr))
+		b |= IRQ2;
+
+	return b;
 }
 
 uint8_t PIA::read_portb_cr() {
+	byte b = portb_cr;
+
 	if (irq_b1)
-		return portb_cr | IRQ1;
-	return portb_cr;
+		b |= IRQ1;
+
+	if (irq_b2 && c2_input(portb_cr))
+		b |= IRQ2;
+
+	return b;
 }
diff --git a/pia.h b/pia.h
index efd30b8..0916194 100644
--- a/pia.h
+++ b/pia.h
@@ -4,11 +4,13 @@
 // https://en.wikipedia.org/wiki/Peripheral_Interface_Adapter
 class PIA {
 public:
-	PIA(): portb(0), portb_cr(0), porta(0), porta_cr(0), irq_a1(false), irq_b1(false) {}
+	PIA(): portb(0), portb_cr(0), porta(0), porta_cr(0),
+		ca1(false), ca2(false), cb1(false), cb2(false),
+		irq_a1(false), irq_a2(false), irq_b1(false), irq_b2(false) {}
 
 	virtual void reset() {
 		portb = portb_cr = porta = porta_cr = 0;
-		irq_a1 = irq_b1 = ca1 = cb1 = false;
+		irq_a1 = irq_a2 = irq_b1 = irq_b2 = ca1 = ca2 = cb1 = cb2 = false;
 	}
 
 	void write(Memory::address, uint8_t);
@@ -18,15 +20,18 @@ public:
 	void restore(Stream &);
 
 	void write_ca1(bool);
+	void write_ca2(bool);
 	void write_cb1(bool);
+	void write_cb2(bool);
 
 	static const uint8_t IRQ1 = 0x80;
+	static const uint8_t IRQ2 = 0x40;
 
 protected:
 	// "device-side" operations (called from memory interface)
-	virtual uint8_t read_porta() { irq_a1 = false; return porta; }
+	virtual uint8_t read_porta() { irq_a1 = irq_a2 = false; return porta; }
 	virtual uint8_t read_porta_cr();
-	virtual uint8_t read_portb() { irq_b1 = false; return portb; }
+	virtual uint8_t read_portb() { irq_b1 = irq_b2 = false; return portb; }
 	virtual uint8_t read_portb_cr();
 
 	virtual void write_porta(uint8_t b) { porta = b; }
@@ -36,7 +41,7 @@ protected:
 
 private:
 	uint8_t portb_cr, portb, porta_cr, porta;
-	bool ca1, irq_a1;
-	bool cb1, irq_b1;
+	bool ca1, ca2, irq_a1, irq_a2;
+	bool cb1, cb2, irq_b1, irq_b2;
 };
 #endif