diff --git a/src/devices/machine/6821pia.cpp b/src/devices/machine/6821pia.cpp
index 60efe473f19..4171b9c6f82 100644
--- a/src/devices/machine/6821pia.cpp
+++ b/src/devices/machine/6821pia.cpp
@@ -910,6 +910,23 @@ void pia6821_device::write_porta(uint8_t data)
 }
 
 
+//-------------------------------------------------
+//  write_porta_line
+//-------------------------------------------------
+
+void pia6821_device::write_porta_line(int line, bool state)
+{
+	if (!m_in_a_pushed)
+		m_port_a_z_mask = 0xff;
+
+	uint8_t mask = 1 << line;
+	if (state)
+		set_a_input(m_in_a | mask, m_port_a_z_mask & ~mask);
+	else
+		set_a_input(m_in_a & ~mask, m_port_a_z_mask & ~mask);
+}
+
+
 //-------------------------------------------------
 //  a_output
 //-------------------------------------------------
@@ -1022,6 +1039,21 @@ void pia6821_device::write_portb(uint8_t data)
 }
 
 
+//-------------------------------------------------
+//  write_portb_line
+//-------------------------------------------------
+
+void pia6821_device::write_portb_line(int line, bool state)
+{
+	uint8_t mask = 1 << line;
+
+	if (state)
+		write_portb(m_in_b | mask);
+	else
+		write_portb(m_in_b & ~mask);
+}
+
+
 //-------------------------------------------------
 //  b_output
 //-------------------------------------------------
diff --git a/src/devices/machine/6821pia.h b/src/devices/machine/6821pia.h
index 8457399cf1a..5682b43ecef 100644
--- a/src/devices/machine/6821pia.h
+++ b/src/devices/machine/6821pia.h
@@ -65,9 +65,19 @@ public:
 
 	DECLARE_WRITE8_MEMBER( porta_w ) { write_porta(data); }
 	void write_porta(uint8_t data);
+	void write_porta_line(int line, bool state);
 	void set_a_input(uint8_t data, uint8_t z_mask);
 	uint8_t a_output();
 
+	DECLARE_WRITE_LINE_MEMBER( pa0_w ) { write_porta_line(0, state); }
+	DECLARE_WRITE_LINE_MEMBER( pa1_w ) { write_porta_line(1, state); }
+	DECLARE_WRITE_LINE_MEMBER( pa2_w ) { write_porta_line(2, state); }
+	DECLARE_WRITE_LINE_MEMBER( pa3_w ) { write_porta_line(3, state); }
+	DECLARE_WRITE_LINE_MEMBER( pa4_w ) { write_porta_line(4, state); }
+	DECLARE_WRITE_LINE_MEMBER( pa5_w ) { write_porta_line(5, state); }
+	DECLARE_WRITE_LINE_MEMBER( pa6_w ) { write_porta_line(6, state); }
+	DECLARE_WRITE_LINE_MEMBER( pa7_w ) { write_porta_line(7, state); }
+
 	DECLARE_WRITE_LINE_MEMBER( ca1_w );
 
 	DECLARE_WRITE_LINE_MEMBER( ca2_w );
@@ -76,8 +86,18 @@ public:
 
 	DECLARE_WRITE8_MEMBER( portb_w ) { write_portb(data); }
 	void write_portb(uint8_t data);
+	void write_portb_line(int line, bool state);
 	uint8_t b_output();
 
+	DECLARE_WRITE_LINE_MEMBER( pb0_w ) { write_portb_line(0, state); }
+	DECLARE_WRITE_LINE_MEMBER( pb1_w ) { write_portb_line(1, state); }
+	DECLARE_WRITE_LINE_MEMBER( pb2_w ) { write_portb_line(2, state); }
+	DECLARE_WRITE_LINE_MEMBER( pb3_w ) { write_portb_line(3, state); }
+	DECLARE_WRITE_LINE_MEMBER( pb4_w ) { write_portb_line(4, state); }
+	DECLARE_WRITE_LINE_MEMBER( pb5_w ) { write_portb_line(5, state); }
+	DECLARE_WRITE_LINE_MEMBER( pb6_w ) { write_portb_line(6, state); }
+	DECLARE_WRITE_LINE_MEMBER( pb7_w ) { write_portb_line(7, state); }
+
 	DECLARE_WRITE_LINE_MEMBER( cb1_w );
 
 	DECLARE_WRITE_LINE_MEMBER( cb2_w );