diff --git a/src/mame/drivers/alphajuno.cpp b/src/mame/drivers/alphajuno.cpp
index 615ea434372..c563109a387 100644
--- a/src/mame/drivers/alphajuno.cpp
+++ b/src/mame/drivers/alphajuno.cpp
@@ -81,7 +81,7 @@ void alphajuno_state::ajuno1_ext_map(address_map &map)
 void alphajuno_state::ajuno2_ext_map(address_map &map)
 {
 	map(0x2000, 0x27ff).mirror(0xd800).ram().share("nvram");
-	map(0x5000, 0x57ff).mirror(0x800).rw("key", FUNC(mb63h149_device::read), FUNC(mb63h149_device::write));
+	map(0x5000, 0x57ff).mirror(0x800).rw("keyscan", FUNC(mb63h149_device::read), FUNC(mb63h149_device::write));
 	map(0x8000, 0x8008).w(FUNC(alphajuno_state::lcd_w));
 }
 
@@ -138,8 +138,8 @@ void alphajuno_state::ajuno2(machine_config &config)
 	ajuno1(config);
 	m_maincpu->set_addrmap(AS_IO, &alphajuno_state::ajuno2_ext_map);
 
-	mb63h149_device &key(MB63H149(config, "key", 12_MHz_XTAL));
-	key.int_callback().set_inputline(m_maincpu, MCS51_INT0_LINE);
+	mb63h149_device &keyscan(MB63H149(config, "keyscan", 12_MHz_XTAL));
+	keyscan.int_callback().set_inputline(m_maincpu, MCS51_INT0_LINE);
 }
 
 void alphajuno_state::mks50(machine_config &config)
diff --git a/src/mame/drivers/roland_d10.cpp b/src/mame/drivers/roland_d10.cpp
index 51067e376f9..0485a892522 100644
--- a/src/mame/drivers/roland_d10.cpp
+++ b/src/mame/drivers/roland_d10.cpp
@@ -235,7 +235,7 @@ void roland_d10_state::d10_map(address_map &map)
 	map(0x0200, 0x0200).w(FUNC(roland_d10_state::so_w));
 	map(0x0300, 0x0300).w(FUNC(roland_d10_state::lcd_data_w));
 	map(0x0380, 0x0380).rw(FUNC(roland_d10_state::lcd_ctrl_r), FUNC(roland_d10_state::lcd_ctrl_w));
-	map(0x0c00, 0x0dff).rw("key", FUNC(mb63h149_device::read), FUNC(mb63h149_device::write));
+	map(0x0c00, 0x0dff).rw("keyscan", FUNC(mb63h149_device::read), FUNC(mb63h149_device::write));
 	map(0x1000, 0x7fff).rom().region("maincpu", 0x1000);
 	map(0x8000, 0xbfff).m(m_bank, FUNC(address_map_bank_device::amap8));
 	map(0xc000, 0xffff).rw(FUNC(roland_d10_state::fixed_r), FUNC(roland_d10_state::fixed_w));
@@ -291,8 +291,8 @@ void roland_d10_state::d10(machine_config &config)
 // Shall become a proper memcard device someday
 	NVRAM( config, m_memcs, nvram_device::DEFAULT_ALL_0 );
 
-	MB63H149(config, "key", 16.384_MHz_XTAL);
-	//key.int_callback().set_inputline(m_maincpu, i8x9x_device::HSI0_LINE);
+	MB63H149(config, "keyscan", 16.384_MHz_XTAL);
+	//keyscan.int_callback().set_inputline(m_maincpu, i8x9x_device::HSI0_LINE);
 
 	screen_device &screen(SCREEN(config, "screen", SCREEN_TYPE_LCD));
 	screen.set_refresh_hz(50);
@@ -319,7 +319,7 @@ void roland_d10_state::d110(machine_config &config)
 	//m_bank->set_data_width(8);
 	m_bank->set_addrmap(0, &roland_d10_state::d110_bank_map);
 
-	config.device_remove("key");
+	config.device_remove("keyscan");
 }
 
 ROM_START( d10 )
diff --git a/src/mame/drivers/roland_d50.cpp b/src/mame/drivers/roland_d50.cpp
index d1e8b694cdc..183a610777c 100644
--- a/src/mame/drivers/roland_d50.cpp
+++ b/src/mame/drivers/roland_d50.cpp
@@ -23,16 +23,24 @@ public:
 	void d550(machine_config &config);
 
 private:
-	void mem_map(address_map &map);
+	void d50_mem_map(address_map &map);
+	void d550_mem_map(address_map &map);
 
 	required_device<upd78312_device> m_maincpu;
 };
 
 
-void roland_d50_state::mem_map(address_map &map)
+void roland_d50_state::d50_mem_map(address_map &map)
 {
 	// Internal ROM is enabled at 0000–1FFF (+5V pullup on EA pin)
-	map(0x2000, 0xfdff).rom().region("progrom", 0x2000); // TODO: banking
+	map(0x2000, 0xf3ff).rom().region("progrom", 0x2000); // TODO: banking?
+	map(0xf400, 0xf7ff).rw("keyscan", FUNC(mb63h149_device::read), FUNC(mb63h149_device::write));
+}
+
+void roland_d50_state::d550_mem_map(address_map &map)
+{
+	// Internal ROM is enabled at 0000–1FFF (+5V pullup on EA pin)
+	map(0x2000, 0xfdff).rom().region("progrom", 0x2000); // TODO: banking?
 }
 
 
@@ -43,12 +51,12 @@ INPUT_PORTS_END
 void roland_d50_state::d50(machine_config &config)
 {
 	UPD78312(config, m_maincpu, 12_MHz_XTAL);
-	m_maincpu->set_addrmap(AS_PROGRAM, &roland_d50_state::mem_map);
+	m_maincpu->set_addrmap(AS_PROGRAM, &roland_d50_state::d50_mem_map);
 
 	// LCD unit is LM402802 (D-50) or LM402551 (D-550)
 
-	MB63H149(config, "key", 32.768_MHz_XTAL / 2); // on Dyna Scan Board
-	//key.int_callback().set_inputline(m_maincpu, upd78312_device::INT2_LINE);
+	MB63H149(config, "keyscan", 32.768_MHz_XTAL / 2); // on Dyna Scan Board
+	//keyscan.int_callback().set_inputline(m_maincpu, upd78312_device::INT2_LINE);
 
 	//MB87136(config, "synthe", 32.768_MHz_XTAL);
 }
@@ -56,8 +64,9 @@ void roland_d50_state::d50(machine_config &config)
 void roland_d50_state::d550(machine_config &config)
 {
 	d50(config);
+	m_maincpu->set_addrmap(AS_PROGRAM, &roland_d50_state::d550_mem_map);
 
-	config.device_remove("key");
+	config.device_remove("keyscan");
 }
 
 // the internal date format for the external program roms is as such:
diff --git a/src/mame/drivers/roland_jx8p.cpp b/src/mame/drivers/roland_jx8p.cpp
index 00b7e49f0e7..7a6dc1bba17 100644
--- a/src/mame/drivers/roland_jx8p.cpp
+++ b/src/mame/drivers/roland_jx8p.cpp
@@ -61,7 +61,7 @@ void roland_jx8p_state::jx8p_assigner_map(address_map &map)
 	map(0x2000, 0x3fff).rw("cartslot", FUNC(generic_slot_device::read_ram), FUNC(generic_slot_device::write_ram));
 	map(0x4000, 0x4007).mirror(0x1ff8).r(FUNC(roland_jx8p_state::switches_r));
 	map(0x6000, 0x6000).mirror(0x1fff).w(FUNC(roland_jx8p_state::leds_w));
-	map(0x8000, 0x87ff).mirror(0x1800).rw("key", FUNC(mb63h149_device::read), FUNC(mb63h149_device::write));
+	map(0x8000, 0x87ff).mirror(0x1800).rw("keyscan", FUNC(mb63h149_device::read), FUNC(mb63h149_device::write));
 	map(0xa000, 0xa7ff).mirror(0x1800).ram().share("nvram");
 	map(0xc000, 0xffff).rom().region("assigner", 0);
 }
@@ -70,7 +70,7 @@ void roland_jx8p_state::superjx_assigner_map(address_map &map)
 {
 	map(0x0000, 0x001f).m(m_assignercpu, FUNC(hd6303r_cpu_device::m6801_io));
 	map(0x0080, 0x00ff).ram(); // internal RAM
-	map(0x1000, 0x17ff).mirror(0x800).rw("key", FUNC(mb63h149_device::read), FUNC(mb63h149_device::write));
+	map(0x1000, 0x17ff).mirror(0x800).rw("keyscan", FUNC(mb63h149_device::read), FUNC(mb63h149_device::write));
 	map(0x2000, 0x3fff).rw("cartslot", FUNC(generic_slot_device::read_ram), FUNC(generic_slot_device::write_ram));
 	map(0x4000, 0x4007).mirror(0xff8).r(FUNC(roland_jx8p_state::switches_r));
 	map(0x5000, 0x5000).mirror(0xfff).w(FUNC(roland_jx8p_state::leds_w));
@@ -315,8 +315,8 @@ void roland_jx8p_state::jx8p(machine_config &config)
 
 	NVRAM(config, "nvram", nvram_device::DEFAULT_ALL_0); // TC5517APL + battery
 
-	mb63h149_device &key(MB63H149(config, "key", 16_MHz_XTAL));
-	key.int_callback().set_inputline(m_assignercpu, HD6301_IRQ_LINE);
+	mb63h149_device &keyscan(MB63H149(config, "keyscan", 16_MHz_XTAL));
+	keyscan.int_callback().set_inputline(m_assignercpu, HD6301_IRQ_LINE);
 
 	GENERIC_CARTSLOT(config, "cartslot", generic_plain_slot, nullptr, "jx8p_cart");
 
@@ -331,7 +331,7 @@ void roland_jx8p_state::jx8po(machine_config &config)
 {
 	jx8p(config);
 
-	MB63H130(config.replace(), "key", 16_MHz_XTAL); // no INT
+	MB63H130(config.replace(), "keyscan", 16_MHz_XTAL); // no INT
 }
 
 void roland_jx8p_state::jx10(machine_config &config)
@@ -341,8 +341,8 @@ void roland_jx8p_state::jx10(machine_config &config)
 
 	NVRAM(config, "nvram", nvram_device::DEFAULT_ALL_0); // TC5564PL-20 + battery
 
-	mb63h149_device &key(MB63H149(config, "key", 16_MHz_XTAL));
-	key.int_callback().set_inputline(m_assignercpu, HD6301_IRQ_LINE);
+	mb63h149_device &keyscan(MB63H149(config, "keyscan", 16_MHz_XTAL));
+	keyscan.int_callback().set_inputline(m_assignercpu, HD6301_IRQ_LINE);
 
 	GENERIC_CARTSLOT(config, "cartslot", generic_plain_slot, nullptr, "jx8p_cart");