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diff --git a/src/v6821.cpp b/src/v6821.cpp
new file mode 100644
index 0000000..0476bee
--- /dev/null
+++ b/src/v6821.cpp
@@ -0,0 +1,165 @@
+//
+// Virtual 6821 Peripheral Interface Adapter (PIA) Emulator v1.0
+//
+// by James Hammons
+// (C) 2022 Underground Software
+//
+// JLH = James Hammons <jlhamm@acm.org>
+//
+// WHO  WHEN        WHAT
+// ---  ----------  ------------------------------------------------------------
+// JLH  12/27/2022  Created this file.  :-)
+
+#include "v6821.h"
+
+//#include "log.h"
+//#include "v6809.h"
+
+// A "1" bit in the DDR means that line is an output
+
+V6821PIA::V6821PIA(): ddra(0), ddrb(0), pa(0), pb(0), cra(0), crb(0), ora(0), orb(0), ca1(false), ca2(false), cb1(false), cb2(false), irqa1(false), irqa2(false), irqb1(false), irqb2(false), irqaState(false), irqbState(false), IRQA(NULL), IRQB(NULL)
+{
+}
+
+V6821PIA::V6821PIA(void (* a)(bool), void (*b)(bool)): ddra(0), ddrb(0), pa(0), pb(0), cra(0), crb(0), ora(0), orb(0), ca1(false), ca2(false), cb1(false), cb2(false), irqa1(false), irqa2(false), irqb1(false), irqb2(false), irqaState(false), irqbState(false), IRQA(a), IRQB(b)
+{
+}
+
+void V6821PIA::Reset(void)
+{
+}
+
+uint8_t V6821PIA::Read(uint8_t addr)
+{
+	switch (addr & 0x03)
+	{
+	case 0:
+		if (cra & 0x04)
+		{
+			// IRQ flags are implicitly cleared by a read
+			irqa1 = irqa2 = false;
+			HandleIRQs();
+
+			return pa & ~ddra;
+		}
+
+		return ddra;
+
+	case 1:
+		return cra | (irqa1 ? 0x80 : 0x00) | (irqa2 ? 0x40 : 0x00);
+
+	case 2:
+		if (crb & 0x04)
+		{
+			// IRQ flags are implicitly cleared by a read
+			irqb1 = irqb2 = false;
+			HandleIRQs();
+
+			return pb & ~ddrb;
+		}
+
+		return ddrb;
+
+	case 3:
+		return crb | (irqb1 ? 0x80 : 0x00) | (irqb2 ? 0x40 : 0x00);
+	}
+
+	// This is only here to silence the the compiler...  :-/
+	return 0xFF;
+}
+
+void V6821PIA::Write(uint8_t addr, uint8_t data)
+{
+	switch (addr & 0x03)
+	{
+	case 0:
+		if (cra & 0x04)
+			pa = data;
+		else
+			ddra = data;
+
+		break;
+
+	case 1:
+		cra = data & 0x3F; // Bits 6-7 are RO
+		HandleIRQs();
+		break;
+
+	case 2:
+		if (crb & 0x04)
+			pb = data;
+		else
+			ddrb = data;
+
+		break;
+
+	case 3:
+		crb = data & 0x3F; // Bits 6-7 are RO
+		HandleIRQs();
+	}
+}
+
+void V6821PIA::CA1(bool state)
+{
+	// Do nothing if nothing changed...
+	if (ca1 == state)
+		return;
+
+	// Check if there's been a transition (bit 1 = lo to hi transition)
+	if ((state && (cra & 0x02)) || (!state && !(cra & 0x02)))
+	{
+		irqa1 = true;
+		HandleIRQs();
+	}
+
+	ca1 = state;
+}
+
+void V6821PIA::CA2(bool state)
+{
+	ca2 = state;
+}
+
+void V6821PIA::CB1(bool state)
+{
+	// Do nothing if nothing changed...
+	if (cb1 == state)
+		return;
+
+	// Check if there's been a transition (bit 1 = lo to hi transition)
+	if ((state && (crb & 0x02)) || (!state && !(crb & 0x02)))
+	{
+		irqb1 = true;
+		HandleIRQs();
+	}
+
+	cb1 = state;
+}
+
+void V6821PIA::CB2(bool state)
+{
+	cb2 = state;
+}
+
+void V6821PIA::HandleIRQs(void)
+{
+	bool newState = (irqa1 && (cra & 0x01)) || (irqa2 && (cra & 0x08));
+
+	if (newState != irqaState)
+	{
+		irqaState = newState;
+
+		if (IRQA)
+			IRQA(irqaState);
+	}
+
+	newState = (irqb1 && (crb & 0x01)) || (irqb2 && (crb & 0x08));
+
+	if (newState != irqbState)
+	{
+		irqbState = newState;
+
+		if (IRQB)
+			IRQB(irqbState);
+	}
+}