diff --git a/src/mame/drivers/ddragon.cpp b/src/mame/drivers/ddragon.cpp
index b3ee1b13082..f4281f9a3b8 100644
--- a/src/mame/drivers/ddragon.cpp
+++ b/src/mame/drivers/ddragon.cpp
@@ -574,11 +574,6 @@ void ddragon_state::dd2_sub_map(address_map &map)
 	map(0xe000, 0xe000).w(FUNC(ddragon_state::ddragon2_sub_irq_w));
 }
 
-void ddragon_state::ddragonba_sub_portmap(address_map &map)
-{
-	map(0x0000, 0x01ff).w(FUNC(ddragon_state::ddragonba_port_w));
-}
-
 
 /*************************************
  *
@@ -1008,14 +1003,15 @@ MACHINE_CONFIG_START(ddragon_state::ddragonb)
 MACHINE_CONFIG_END
 
 
-MACHINE_CONFIG_START(ddragon_state::ddragonba)
+void ddragon_state::ddragonba(machine_config &config)
+{
 	ddragon(config);
 
 	/* basic machine hardware */
-	MCFG_DEVICE_REPLACE("sub", M6803, MAIN_CLOCK / 2)  /* 6MHz / 4 internally */
-	MCFG_DEVICE_PROGRAM_MAP(ddragonba_sub_map)
-	MCFG_DEVICE_IO_MAP(ddragonba_sub_portmap)
-MACHINE_CONFIG_END
+	m6803_cpu_device &sub(M6803(config.replace(), "sub", MAIN_CLOCK / 2));  // 6MHz / 4 internally
+	sub.set_addrmap(AS_PROGRAM, &ddragon_state::ddragonba_sub_map);
+	sub.out_p2_cb().set(FUNC(ddragon_state::ddragonba_port_w));
+}
 
 
 MACHINE_CONFIG_START(ddragon_state::ddragon6809)
diff --git a/src/mame/drivers/ltd.cpp b/src/mame/drivers/ltd.cpp
index 3d7f5976fea..3e4f83fbdcf 100644
--- a/src/mame/drivers/ltd.cpp
+++ b/src/mame/drivers/ltd.cpp
@@ -81,7 +81,6 @@ private:
 	DECLARE_WRITE8_MEMBER(count_reset_w);
 	TIMER_DEVICE_CALLBACK_MEMBER(timer_r);
 	void ltd3_map(address_map &map);
-	void ltd4_io(address_map &map);
 	void ltd4_map(address_map &map);
 
 	bool m_timer_r;
@@ -123,12 +122,6 @@ void ltd_state::ltd4_map(address_map &map)
 	map(0xc000, 0xdfff).rom().mirror(0x2000).region("roms", 0);
 }
 
-void ltd_state::ltd4_io(address_map &map)
-{
-	map(0x0100, 0x0100).rw(FUNC(ltd_state::port1_r), FUNC(ltd_state::port1_w));
-	map(0x0101, 0x0101).rw(FUNC(ltd_state::port2_r), FUNC(ltd_state::port2_w));
-}
-
 // bits 6,7 not connected to data bus
 // 1=does something in Atlantis; 2=does something in Black Hole; note that sometimes pressing G or H will reboot the machine.
 static INPUT_PORTS_START( ltd3 )
@@ -548,9 +541,12 @@ MACHINE_CONFIG_END
 
 MACHINE_CONFIG_START(ltd_state::ltd4)
 	/* basic machine hardware */
-	MCFG_DEVICE_ADD("maincpu", M6803, XTAL(3'579'545)) // guess, no details available
-	MCFG_DEVICE_PROGRAM_MAP(ltd4_map)
-	MCFG_DEVICE_IO_MAP(ltd4_io)
+	m6803_cpu_device &maincpu(M6803(config, "maincpu", XTAL(3'579'545))); // guess, no details available
+	maincpu.set_addrmap(AS_PROGRAM, &ltd_state::ltd4_map);
+	maincpu.in_p1_cb().set(FUNC(ltd_state::port1_r));
+	maincpu.out_p1_cb().set(FUNC(ltd_state::port1_w));
+	maincpu.in_p2_cb().set(FUNC(ltd_state::port2_r));
+	maincpu.out_p2_cb().set(FUNC(ltd_state::port2_w));
 
 	NVRAM(config, "nvram", nvram_device::DEFAULT_ALL_0);
 
diff --git a/src/mame/includes/ddragon.h b/src/mame/includes/ddragon.h
index edd90fa3493..eedfce5cf5c 100644
--- a/src/mame/includes/ddragon.h
+++ b/src/mame/includes/ddragon.h
@@ -152,7 +152,6 @@ private:
 	void dd2_sub_map(address_map &map);
 	void ddragon_map(address_map &map);
 	void ddragonba_sub_map(address_map &map);
-	void ddragonba_sub_portmap(address_map &map);
 	void sound_map(address_map &map);
 	void sub_map(address_map &map);
 };