diff --git a/scripts/src/bus.lua b/scripts/src/bus.lua
index 6808a5beb39..fd54182bc0a 100644
--- a/scripts/src/bus.lua
+++ b/scripts/src/bus.lua
@@ -4014,6 +4014,8 @@ if (BUSES["VTECH_MEMEXP"]~=null) then
 		MAME_DIR .. "src/devices/bus/vtech/memexp/rs232.h",
 		MAME_DIR .. "src/devices/bus/vtech/memexp/rtty.cpp",
 		MAME_DIR .. "src/devices/bus/vtech/memexp/rtty.h",
+		MAME_DIR .. "src/devices/bus/vtech/memexp/sdloader.cpp",
+		MAME_DIR .. "src/devices/bus/vtech/memexp/sdloader.h",
 		MAME_DIR .. "src/devices/bus/vtech/memexp/wordpro.cpp",
 		MAME_DIR .. "src/devices/bus/vtech/memexp/wordpro.h",
 	}
@@ -4030,6 +4032,8 @@ if (BUSES["VTECH_IOEXP"]~=null) then
 		MAME_DIR .. "src/devices/bus/vtech/ioexp/ioexp.h",
 		MAME_DIR .. "src/devices/bus/vtech/ioexp/carts.cpp",
 		MAME_DIR .. "src/devices/bus/vtech/ioexp/carts.h",
+		MAME_DIR .. "src/devices/bus/vtech/ioexp/lpen.cpp",
+		MAME_DIR .. "src/devices/bus/vtech/ioexp/lpen.h",
 		MAME_DIR .. "src/devices/bus/vtech/ioexp/joystick.cpp",
 		MAME_DIR .. "src/devices/bus/vtech/ioexp/joystick.h",
 		MAME_DIR .. "src/devices/bus/vtech/ioexp/printer.cpp",
diff --git a/src/devices/bus/vtech/ioexp/ioexp.cpp b/src/devices/bus/vtech/ioexp/ioexp.cpp
index 27a517fabb1..475f287201e 100644
--- a/src/devices/bus/vtech/ioexp/ioexp.cpp
+++ b/src/devices/bus/vtech/ioexp/ioexp.cpp
@@ -1,5 +1,5 @@
-// license:GPL-2.0+
-// copyright-holders:Dirk Best
+// license: GPL-2.0+
+// copyright-holders: Dirk Best
 /***************************************************************************
 
     VTech Laser/VZ I/O Expansion Slot
@@ -30,7 +30,7 @@ DEFINE_DEVICE_TYPE(VTECH_IOEXP_SLOT, vtech_ioexp_slot_device, "vtech_ioexp_slot"
 vtech_ioexp_slot_device::vtech_ioexp_slot_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) :
 	device_t(mconfig, VTECH_IOEXP_SLOT, tag, owner, clock),
 	device_single_card_slot_interface<device_vtech_ioexp_interface>(mconfig, *this),
-	m_io(*this, finder_base::DUMMY_TAG, -1)
+	m_iospace(*this, finder_base::DUMMY_TAG, -1)
 {
 }
 
@@ -48,6 +48,24 @@ vtech_ioexp_slot_device::~vtech_ioexp_slot_device()
 
 void vtech_ioexp_slot_device::device_start()
 {
+	// get inserted module
+	m_module = get_card_device();
+
+	// install io access taps
+	m_iospace->install_readwrite_tap
+	(
+		0x00, 0xff, "io_tap",
+		[this](offs_t offset, uint8_t &data, uint8_t mem_mask)
+		{
+			if (m_module)
+				data &= m_module->iorq_r(offset);
+		},
+		[this](offs_t offset, uint8_t &data, uint8_t mem_mask)
+		{
+			if (m_module)
+				m_module->iorq_w(offset, data);
+		}
+	);
 }
 
 
@@ -72,3 +90,52 @@ device_vtech_ioexp_interface::device_vtech_ioexp_interface(const machine_config
 device_vtech_ioexp_interface::~device_vtech_ioexp_interface()
 {
 }
+
+
+//**************************************************************************
+//  BASE DEVICE
+//**************************************************************************
+
+//-------------------------------------------------
+//  vtech_ioexp_device - constructor
+//-------------------------------------------------
+
+vtech_ioexp_device::vtech_ioexp_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, uint32_t clock) :
+	device_t(mconfig, type, tag, owner, clock),
+	device_vtech_ioexp_interface(mconfig, *this),
+	m_io(*this, "iospace")
+{
+}
+
+//-------------------------------------------------
+//  device_add_mconfig - add device configuration
+//-------------------------------------------------
+
+void vtech_ioexp_device::device_add_mconfig(machine_config &config)
+{
+	ADDRESS_MAP_BANK(config, m_io);
+	m_io->set_addrmap(AS_PROGRAM, &vtech_ioexp_device::io_map);
+	m_io->set_data_width(8);
+	m_io->set_addr_width(16);
+}
+
+//-------------------------------------------------
+//  device_start - device-specific startup
+//-------------------------------------------------
+
+void vtech_ioexp_device::device_start()
+{
+	// silence unmapped warnings, or we'll get them for everything the
+	// expansion device doesn't handle
+	m_io->set_log_unmap(false);
+}
+
+uint8_t vtech_ioexp_device::iorq_r(offs_t offset)
+{
+	return m_io->read8(offset);
+}
+
+void vtech_ioexp_device::iorq_w(offs_t offset, uint8_t data)
+{
+	m_io->write8(offset, data);
+}
diff --git a/src/devices/bus/vtech/ioexp/ioexp.h b/src/devices/bus/vtech/ioexp/ioexp.h
index 354d9fc46a2..a4854483376 100644
--- a/src/devices/bus/vtech/ioexp/ioexp.h
+++ b/src/devices/bus/vtech/ioexp/ioexp.h
@@ -1,5 +1,5 @@
-// license:GPL-2.0+
-// copyright-holders:Dirk Best
+// license: GPL-2.0+
+// copyright-holders: Dirk Best
 /***************************************************************************
 
     VTech Laser/VZ I/O Expansion Slot
@@ -29,9 +29,12 @@
 
 #pragma once
 
+#include "machine/bankdev.h"
+
 // include here so drivers don't need to
 #include "carts.h"
 
+
 //**************************************************************************
 //  TYPE DEFINITIONS
 //**************************************************************************
@@ -54,13 +57,16 @@ public:
 	vtech_ioexp_slot_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock);
 	virtual ~vtech_ioexp_slot_device();
 
-	template <typename T> void set_io_space(T &&tag, int spacenum) { m_io.set_tag(std::forward<T>(tag), spacenum); }
+	template <typename T> void set_iospace(T &&tag, int spacenum) { m_iospace.set_tag(std::forward<T>(tag), spacenum); }
 
 protected:
 	// device-level overrides
 	virtual void device_start() override;
 
-	required_address_space m_io;
+private:
+	required_address_space m_iospace;
+
+	device_vtech_ioexp_interface *m_module;
 };
 
 // class representing interface-specific live ioexp device
@@ -70,14 +76,35 @@ public:
 	// construction/destruction
 	virtual ~device_vtech_ioexp_interface();
 
+	virtual uint8_t iorq_r(offs_t offset) { return 0xff; }
+	virtual void iorq_w(offs_t offset, uint8_t data) { }
+
 protected:
 	device_vtech_ioexp_interface(const machine_config &mconfig, device_t &device);
 
-	address_space &io_space() { return *m_slot->m_io; }
-
 	vtech_ioexp_slot_device *m_slot;
 };
 
+// base io expansion device
+class vtech_ioexp_device : public device_t, public device_vtech_ioexp_interface
+{
+public:
+	// construction/destruction
+	vtech_ioexp_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, uint32_t clock);
+
+	// from host
+	virtual uint8_t iorq_r(offs_t offset) override;
+	virtual void iorq_w(offs_t offset, uint8_t data) override;
+
+protected:
+	virtual void device_add_mconfig(machine_config &config) override;
+	virtual void device_start() override;
+
+	virtual void io_map(address_map &map) { };
+
+	required_device<address_map_bank_device> m_io;
+};
+
 // device type definition
 DECLARE_DEVICE_TYPE(VTECH_IOEXP_SLOT, vtech_ioexp_slot_device)
 
diff --git a/src/devices/bus/vtech/ioexp/joystick.cpp b/src/devices/bus/vtech/ioexp/joystick.cpp
index a352c555fbd..f54125c64ae 100644
--- a/src/devices/bus/vtech/ioexp/joystick.cpp
+++ b/src/devices/bus/vtech/ioexp/joystick.cpp
@@ -19,6 +19,16 @@
 
 DEFINE_DEVICE_TYPE(VTECH_JOYSTICK_INTERFACE, vtech_joystick_interface_device, "vtech_joystick", "Laser/VZ Joystick Interface")
 
+//-------------------------------------------------
+//  io_map - memory space address map
+//-------------------------------------------------
+
+void vtech_joystick_interface_device::io_map(address_map &map)
+{
+	map.unmap_value_high();
+	map(0x20, 0x2f).r(FUNC(vtech_joystick_interface_device::joystick_r));
+}
+
 //-------------------------------------------------
 //  input_ports - device-specific input ports
 //-------------------------------------------------
@@ -66,8 +76,7 @@ ioport_constructor vtech_joystick_interface_device::device_input_ports() const
 //-------------------------------------------------
 
 vtech_joystick_interface_device::vtech_joystick_interface_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) :
-	device_t(mconfig, VTECH_JOYSTICK_INTERFACE, tag, owner, clock),
-	device_vtech_ioexp_interface(mconfig, *this),
+	vtech_ioexp_device(mconfig, VTECH_JOYSTICK_INTERFACE, tag, owner, clock),
 	m_joy0(*this, "joystick_0"),
 	m_joy0_arm(*this, "joystick_0_arm"),
 	m_joy1(*this, "joystick_1"),
@@ -81,15 +90,7 @@ vtech_joystick_interface_device::vtech_joystick_interface_device(const machine_c
 
 void vtech_joystick_interface_device::device_start()
 {
-}
-
-//-------------------------------------------------
-//  device_reset - device-specific reset
-//-------------------------------------------------
-
-void vtech_joystick_interface_device::device_reset()
-{
-	io_space().install_read_handler(0x20, 0x2f, read8sm_delegate(*this, FUNC(vtech_joystick_interface_device::joystick_r)));
+	vtech_ioexp_device::device_start();
 }
 
 
diff --git a/src/devices/bus/vtech/ioexp/joystick.h b/src/devices/bus/vtech/ioexp/joystick.h
index f648bb9e469..2d59f7d4951 100644
--- a/src/devices/bus/vtech/ioexp/joystick.h
+++ b/src/devices/bus/vtech/ioexp/joystick.h
@@ -21,9 +21,9 @@
 //  TYPE DEFINITIONS
 //**************************************************************************
 
-// ======================> joystick_interface_device
+// ======================> vtech_joystick_interface_device
 
-class vtech_joystick_interface_device : public device_t, public device_vtech_ioexp_interface
+class vtech_joystick_interface_device : public vtech_ioexp_device
 {
 public:
 	// construction/destruction
@@ -34,7 +34,8 @@ public:
 protected:
 	virtual ioport_constructor device_input_ports() const override;
 	virtual void device_start() override;
-	virtual void device_reset() override;
+
+	virtual void io_map(address_map &map) override;
 
 private:
 	required_ioport m_joy0;
diff --git a/src/devices/bus/vtech/ioexp/lpen.cpp b/src/devices/bus/vtech/ioexp/lpen.cpp
new file mode 100644
index 00000000000..aa0d9ee8e10
--- /dev/null
+++ b/src/devices/bus/vtech/ioexp/lpen.cpp
@@ -0,0 +1,63 @@
+// license: GPL-2.0+
+// copyright-holders: Dirk Best
+/***************************************************************************
+
+    VTech Laser Lightpen Interface
+
+	Skeleton just to document the I/O ports used
+
+***************************************************************************/
+
+#include "emu.h"
+#include "lpen.h"
+
+
+//**************************************************************************
+//  DEVICE DEFINITIONS
+//**************************************************************************
+
+DEFINE_DEVICE_TYPE(VTECH_LPEN_INTERFACE, vtech_lpen_interface_device, "vtech_lpen", "Laser/VZ Lightpen Interface")
+
+//-------------------------------------------------
+//  io_map - memory space address map
+//-------------------------------------------------
+
+void vtech_lpen_interface_device::io_map(address_map &map)
+{
+	map.unmap_value_high();
+	map(0x40, 0x4f).r(FUNC(vtech_lpen_interface_device::lpen_r));
+}
+
+
+//**************************************************************************
+//  LIVE DEVICE
+//**************************************************************************
+
+//-------------------------------------------------
+//  vtech_lpen_interface_device - constructor
+//-------------------------------------------------
+
+vtech_lpen_interface_device::vtech_lpen_interface_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) :
+	vtech_ioexp_device(mconfig, VTECH_LPEN_INTERFACE, tag, owner, clock)
+{
+}
+
+//-------------------------------------------------
+//  device_start - device-specific startup
+//-------------------------------------------------
+
+void vtech_lpen_interface_device::device_start()
+{
+	vtech_ioexp_device::device_start();
+}
+
+
+//**************************************************************************
+//  IMPLEMENTATION
+//**************************************************************************
+
+uint8_t vtech_lpen_interface_device::lpen_r(offs_t offset)
+{
+	logerror("lpen_r %02x\n", offset);
+	return 0xff;
+}
diff --git a/src/devices/bus/vtech/ioexp/lpen.h b/src/devices/bus/vtech/ioexp/lpen.h
new file mode 100644
index 00000000000..95759e5fcff
--- /dev/null
+++ b/src/devices/bus/vtech/ioexp/lpen.h
@@ -0,0 +1,43 @@
+// license: GPL-2.0+
+// copyright-holders: Dirk Best
+/***************************************************************************
+
+    VTech Laser Lightpen Interface
+
+***************************************************************************/
+
+#ifndef MAME_BUS_VTECH_IOEXP_LPEN_H
+#define MAME_BUS_VTECH_IOEXP_LPEN_H
+
+#pragma once
+
+#include "ioexp.h"
+
+
+//**************************************************************************
+//  TYPE DEFINITIONS
+//**************************************************************************
+
+// ======================> vtech_lpen_interface_device
+
+class vtech_lpen_interface_device : public vtech_ioexp_device
+{
+public:
+	// construction/destruction
+	vtech_lpen_interface_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock);
+
+	static constexpr feature_type unemulated_features() { return feature::CONTROLS; }
+
+protected:
+	virtual void device_start() override;
+
+	virtual void io_map(address_map &map) override;
+
+private:
+	uint8_t lpen_r(offs_t offset);
+};
+
+// device type definition
+DECLARE_DEVICE_TYPE(VTECH_LPEN_INTERFACE, vtech_lpen_interface_device)
+
+#endif // MAME_BUS_VTECH_IOEXP_LPEN_H
diff --git a/src/devices/bus/vtech/ioexp/printer.cpp b/src/devices/bus/vtech/ioexp/printer.cpp
index fa452ce3928..b5eaa4e8a4b 100644
--- a/src/devices/bus/vtech/ioexp/printer.cpp
+++ b/src/devices/bus/vtech/ioexp/printer.cpp
@@ -19,12 +19,26 @@
 
 DEFINE_DEVICE_TYPE(VTECH_PRINTER_INTERFACE, vtech_printer_interface_device, "vtech_printer", "Laser/VZ Printer Interface")
 
+//-------------------------------------------------
+//  io_map - memory space address map
+//-------------------------------------------------
+
+void vtech_printer_interface_device::io_map(address_map &map)
+{
+	map.unmap_value_high();
+	map(0x00, 0x00).r(FUNC(vtech_printer_interface_device::busy_r));
+	map(0x0d, 0x0d).w(FUNC(vtech_printer_interface_device::strobe_w));
+	map(0x0e, 0x0e).w(m_latch, FUNC(output_latch_device::write));
+}
+
 //-------------------------------------------------
 //  device_add_mconfig - add device configuration
 //-------------------------------------------------
 
 void vtech_printer_interface_device::device_add_mconfig(machine_config &config)
 {
+	vtech_ioexp_device::device_add_mconfig(config);
+
 	CENTRONICS(config, m_centronics, centronics_devices, "printer");
 	m_centronics->busy_handler().set(FUNC(vtech_printer_interface_device::busy_w));
 
@@ -42,8 +56,7 @@ void vtech_printer_interface_device::device_add_mconfig(machine_config &config)
 //-------------------------------------------------
 
 vtech_printer_interface_device::vtech_printer_interface_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) :
-	device_t(mconfig, VTECH_PRINTER_INTERFACE, tag, owner, clock),
-	device_vtech_ioexp_interface(mconfig, *this),
+	vtech_ioexp_device(mconfig, VTECH_PRINTER_INTERFACE, tag, owner, clock),
 	m_centronics(*this, "centronics"),
 	m_latch(*this, "latch"),
 	m_centronics_busy(0)
@@ -56,17 +69,10 @@ vtech_printer_interface_device::vtech_printer_interface_device(const machine_con
 
 void vtech_printer_interface_device::device_start()
 {
-}
+	vtech_ioexp_device::device_start();
 
-//-------------------------------------------------
-//  device_reset - device-specific reset
-//-------------------------------------------------
-
-void vtech_printer_interface_device::device_reset()
-{
-	io_space().install_read_handler(0x00, 0x00, read8smo_delegate(*this, FUNC(vtech_printer_interface_device::busy_r)));
-	io_space().install_write_handler(0x0d, 0x0d, write8smo_delegate(*this, FUNC(vtech_printer_interface_device::strobe_w)));
-	io_space().install_write_handler(0x0e, 0x0e, write8smo_delegate(*m_latch, FUNC(output_latch_device::write)));
+	// register for save states
+	save_item(NAME(m_centronics_busy));
 }
 
 
diff --git a/src/devices/bus/vtech/ioexp/printer.h b/src/devices/bus/vtech/ioexp/printer.h
index 58f8493f3ab..be25c7fd614 100644
--- a/src/devices/bus/vtech/ioexp/printer.h
+++ b/src/devices/bus/vtech/ioexp/printer.h
@@ -21,9 +21,9 @@
 //  TYPE DEFINITIONS
 //**************************************************************************
 
-// ======================> printer_interface_device
+// ======================> vtech_printer_interface_device
 
-class vtech_printer_interface_device : public device_t, public device_vtech_ioexp_interface
+class vtech_printer_interface_device : public vtech_ioexp_device
 {
 public:
 	// construction/destruction
@@ -32,16 +32,17 @@ public:
 protected:
 	virtual void device_add_mconfig(machine_config &config) override;
 	virtual void device_start() override;
-	virtual void device_reset() override;
+
+	virtual void io_map(address_map &map) override;
 
 private:
+	required_device<centronics_device> m_centronics;
+	required_device<output_latch_device> m_latch;
+
 	DECLARE_WRITE_LINE_MEMBER( busy_w );
 	uint8_t busy_r();
 	void strobe_w(uint8_t data);
 
-	required_device<centronics_device> m_centronics;
-	required_device<output_latch_device> m_latch;
-
 	int m_centronics_busy;
 };
 
diff --git a/src/devices/bus/vtech/memexp/carts.cpp b/src/devices/bus/vtech/memexp/carts.cpp
index 41bd9d42c0f..73a59b9fcdb 100644
--- a/src/devices/bus/vtech/memexp/carts.cpp
+++ b/src/devices/bus/vtech/memexp/carts.cpp
@@ -13,6 +13,7 @@
 #include "memory.h"
 #include "rs232.h"
 #include "rtty.h"
+#include "sdloader.h"
 #include "wordpro.h"
 
 
@@ -25,5 +26,6 @@ void vtech_memexp_carts(device_slot_interface &device)
 	device.option_add("laser_64k",    VTECH_LASER_64K);
 	device.option_add("rs232",        VTECH_RS232_INTERFACE);
 	device.option_add("rtty",         VTECH_RTTY_INTERFACE);
+	device.option_add("sdloader",     VTECH_SDLOADER);
 	device.option_add("wordpro",      VTECH_WORDPRO);
 }
diff --git a/src/devices/bus/vtech/memexp/floppy.cpp b/src/devices/bus/vtech/memexp/floppy.cpp
index 60e6a5166fc..47970b9a142 100644
--- a/src/devices/bus/vtech/memexp/floppy.cpp
+++ b/src/devices/bus/vtech/memexp/floppy.cpp
@@ -21,12 +21,27 @@
 
 DEFINE_DEVICE_TYPE(VTECH_FLOPPY_CONTROLLER, vtech_floppy_controller_device, "vtech_fdc", "Laser/VZ Floppy Disk Controller")
 
-void vtech_floppy_controller_device::map(address_map &map)
+//-------------------------------------------------
+//  mem_map - memory space address map
+//-------------------------------------------------
+
+void vtech_floppy_controller_device::mem_map(address_map &map)
 {
-	map(0, 0).w(FUNC(vtech_floppy_controller_device::latch_w));
-	map(1, 1).r(FUNC(vtech_floppy_controller_device::shifter_r));
-	map(2, 2).r(FUNC(vtech_floppy_controller_device::rd_r));
-	map(3, 3).r(FUNC(vtech_floppy_controller_device::wpt_r));
+	map.unmap_value_high();
+	map(0x4000, 0x5fff).rom().region("software", 0);
+}
+
+//-------------------------------------------------
+//  io_map - io space address map
+//-------------------------------------------------
+
+void vtech_floppy_controller_device::io_map(address_map &map)
+{
+	map.unmap_value_high();
+	map(0x10, 0x10).w(FUNC(vtech_floppy_controller_device::latch_w));
+	map(0x11, 0x11).r(FUNC(vtech_floppy_controller_device::shifter_r));
+	map(0x12, 0x12).r(FUNC(vtech_floppy_controller_device::rd_r));
+	map(0x13, 0x13).r(FUNC(vtech_floppy_controller_device::wpt_r));
 }
 
 //-------------------------------------------------
@@ -34,7 +49,7 @@ void vtech_floppy_controller_device::map(address_map &map)
 //-------------------------------------------------
 
 ROM_START( floppy )
-	ROM_REGION(0x3000, "software", 0)
+	ROM_REGION(0x2000, "software", 0)
 	ROM_LOAD("vzdos.rom", 0x0000, 0x2000, CRC(b6ed6084) SHA1(59d1cbcfa6c5e1906a32704fbf0d9670f0d1fd8b))
 ROM_END
 
@@ -61,7 +76,12 @@ void vtech_floppy_controller_device::floppy_formats(format_registration &fr)
 
 void vtech_floppy_controller_device::device_add_mconfig(machine_config &config)
 {
+	vtech_memexp_device::device_add_mconfig(config);
+
 	VTECH_MEMEXP_SLOT(config, m_memexp);
+	m_memexp->set_memspace(m_mem, AS_PROGRAM);
+	m_memexp->set_iospace(m_io, AS_PROGRAM);
+
 	FLOPPY_CONNECTOR(config, m_floppy0, laser_floppies, "525", floppy_formats);
 	FLOPPY_CONNECTOR(config, m_floppy1, laser_floppies, "525", floppy_formats);
 }
@@ -76,8 +96,7 @@ void vtech_floppy_controller_device::device_add_mconfig(machine_config &config)
 //-------------------------------------------------
 
 vtech_floppy_controller_device::vtech_floppy_controller_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) :
-	device_t(mconfig, VTECH_FLOPPY_CONTROLLER, tag, owner, clock),
-	device_vtech_memexp_interface(mconfig, *this),
+	vtech_memexp_device(mconfig, VTECH_FLOPPY_CONTROLLER, tag, owner, clock),
 	m_memexp(*this, "mem"),
 	m_floppy0(*this, "0"),
 	m_floppy1(*this, "1"),
@@ -91,6 +110,9 @@ vtech_floppy_controller_device::vtech_floppy_controller_device(const machine_con
 
 void vtech_floppy_controller_device::device_start()
 {
+	vtech_memexp_device::device_start();
+
+	// register for save states
 	save_item(NAME(m_latch));
 	save_item(NAME(m_shifter));
 	save_item(NAME(m_latching_inverter));
@@ -101,13 +123,11 @@ void vtech_floppy_controller_device::device_start()
 
 	// TODO: save m_write_buffer and rebuild m_floppy after load
 
-	uint8_t *bios = memregion("software")->base();
-
 	// Obvious bugs... must have worked by sheer luck and very subtle
 	// timings.  Our current z80 is not subtle enough.
-
-	bios[0x1678] = 0x75;
-	bios[0x1688] = 0x85;
+	uint8_t *rom = memregion("software")->base();
+	rom[0x1678] = 0x75;
+	rom[0x1688] = 0x85;
 }
 
 //-------------------------------------------------
@@ -116,10 +136,6 @@ void vtech_floppy_controller_device::device_start()
 
 void vtech_floppy_controller_device::device_reset()
 {
-	program_space().install_rom(0x4000, 0x5fff, memregion("software")->base());
-
-	io_space().install_device(0x10, 0x1f, *this, &vtech_floppy_controller_device::map);
-
 	m_latch = 0x00;
 	m_floppy = nullptr;
 	m_current_cyl = 0;
diff --git a/src/devices/bus/vtech/memexp/floppy.h b/src/devices/bus/vtech/memexp/floppy.h
index 78079cea461..167cbf5ba63 100644
--- a/src/devices/bus/vtech/memexp/floppy.h
+++ b/src/devices/bus/vtech/memexp/floppy.h
@@ -24,7 +24,7 @@
 
 // ======================> vtech_floppy_controller_device
 
-class vtech_floppy_controller_device : public device_t, public device_vtech_memexp_interface
+class vtech_floppy_controller_device : public vtech_memexp_device
 {
 public:
 	// construction/destruction
@@ -36,8 +36,15 @@ protected:
 	virtual void device_start() override;
 	virtual void device_reset() override;
 
+	virtual void mem_map(address_map &map) override;
+	virtual void io_map(address_map &map) override;
+
 private:
-	void map(address_map &map);
+	required_device<vtech_memexp_slot_device> m_memexp;
+	required_device<floppy_connector> m_floppy0, m_floppy1;
+	floppy_image_device *m_floppy;
+
+	static void floppy_formats(format_registration &fr);
 
 	void latch_w(uint8_t data);
 	uint8_t shifter_r();
@@ -48,12 +55,6 @@ private:
 	void update_latching_inverter();
 	void flush_writes(bool keep_margin = false);
 
-	static void floppy_formats(format_registration &fr);
-
-	required_device<vtech_memexp_slot_device> m_memexp;
-	required_device<floppy_connector> m_floppy0, m_floppy1;
-	floppy_image_device *m_floppy;
-
 	uint8_t m_latch, m_shifter;
 	bool m_latching_inverter;
 	int m_current_cyl;
diff --git a/src/devices/bus/vtech/memexp/memexp.cpp b/src/devices/bus/vtech/memexp/memexp.cpp
index d857ccf3d0b..74d2213009a 100644
--- a/src/devices/bus/vtech/memexp/memexp.cpp
+++ b/src/devices/bus/vtech/memexp/memexp.cpp
@@ -1,5 +1,5 @@
-// license:GPL-2.0+
-// copyright-holders:Dirk Best
+// license: GPL-2.0+
+// copyright-holders: Dirk Best
 /***************************************************************************
 
     VTech Laser/VZ Memory Expansion Slot
@@ -30,8 +30,8 @@ DEFINE_DEVICE_TYPE(VTECH_MEMEXP_SLOT, vtech_memexp_slot_device, "vtech_memexp_sl
 vtech_memexp_slot_device::vtech_memexp_slot_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) :
 	device_t(mconfig, VTECH_MEMEXP_SLOT, tag, owner, clock),
 	device_single_card_slot_interface<device_vtech_memexp_interface>(mconfig, *this),
-	m_program(*this, finder_base::DUMMY_TAG, -1),
-	m_io(*this, finder_base::DUMMY_TAG, -1),
+	m_memspace(*this, finder_base::DUMMY_TAG, -1),
+	m_iospace(*this, finder_base::DUMMY_TAG, -1),
 	m_int_handler(*this),
 	m_nmi_handler(*this),
 	m_reset_handler(*this)
@@ -46,34 +46,47 @@ vtech_memexp_slot_device::~vtech_memexp_slot_device()
 {
 }
 
-//-------------------------------------------------
-//  device_config_complete - perform any
-//  operations now that the configuration is
-//  complete
-//-------------------------------------------------
-
-void vtech_memexp_slot_device::device_config_complete()
-{
-	// for passthrough connectors, use the parent slot's spaces
-	if (dynamic_cast<device_vtech_memexp_interface *>(owner()) != nullptr)
-	{
-		auto parent = dynamic_cast<vtech_memexp_slot_device *>(owner()->owner());
-		if (parent != nullptr)
-		{
-			if (m_program.finder_tag() == finder_base::DUMMY_TAG)
-				m_program.set_tag(parent->m_program, parent->m_program.spacenum());
-			if (m_io.finder_tag() == finder_base::DUMMY_TAG)
-				m_io.set_tag(parent->m_io, parent->m_io.spacenum());
-		}
-	}
-}
-
 //-------------------------------------------------
 //  device_start - device-specific startup
 //-------------------------------------------------
 
 void vtech_memexp_slot_device::device_start()
 {
+	// get inserted module
+	m_module = get_card_device();
+
+	// install memory access taps
+	m_memspace->install_readwrite_tap
+	(
+		0x0000, 0xffff, "mem_tap",
+		[this](offs_t offset, uint8_t &data, uint8_t mem_mask)
+		{
+			if (m_module)
+				data &= m_module->mreq_r(offset);
+		},
+		[this](offs_t offset, uint8_t &data, uint8_t mem_mask)
+		{
+			if (m_module)
+				m_module->mreq_w(offset, data);
+		}
+	);
+
+	// install io access taps
+	m_iospace->install_readwrite_tap
+	(
+		0x00, 0xff, "io_tap",
+		[this](offs_t offset, uint8_t &data, uint8_t mem_mask)
+		{
+			if (m_module)
+				data &= m_module->iorq_r(offset);
+		},
+		[this](offs_t offset, uint8_t &data, uint8_t mem_mask)
+		{
+			if (m_module)
+				m_module->iorq_w(offset, data);
+		}
+	);
+
 	// resolve callbacks
 	m_int_handler.resolve_safe();
 	m_nmi_handler.resolve_safe();
@@ -102,3 +115,69 @@ device_vtech_memexp_interface::device_vtech_memexp_interface(const machine_confi
 device_vtech_memexp_interface::~device_vtech_memexp_interface()
 {
 }
+
+
+//**************************************************************************
+//  BASE DEVICE
+//**************************************************************************
+
+//-------------------------------------------------
+//  vtech_memexp_device - constructor
+//-------------------------------------------------
+
+vtech_memexp_device::vtech_memexp_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, uint32_t clock) :
+	device_t(mconfig, type, tag, owner, clock),
+	device_vtech_memexp_interface(mconfig, *this),
+	m_mem(*this, "memspace"),
+	m_io(*this, "iospace")
+{
+}
+
+//-------------------------------------------------
+//  device_add_mconfig - add device configuration
+//-------------------------------------------------
+
+void vtech_memexp_device::device_add_mconfig(machine_config &config)
+{
+	ADDRESS_MAP_BANK(config, m_mem);
+	m_mem->set_addrmap(AS_PROGRAM, &vtech_memexp_device::mem_map);
+	m_mem->set_data_width(8);
+	m_mem->set_addr_width(16);
+
+	ADDRESS_MAP_BANK(config, m_io);
+	m_io->set_addrmap(AS_PROGRAM, &vtech_memexp_device::io_map);
+	m_io->set_data_width(8);
+	m_io->set_addr_width(16);
+}
+
+//-------------------------------------------------
+//  device_start - device-specific startup
+//-------------------------------------------------
+
+void vtech_memexp_device::device_start()
+{
+	// silence unmapped warnings, or we'll get them for everything the
+	// expansion device doesn't handle
+	m_mem->set_log_unmap(false);
+	m_io->set_log_unmap(false);
+}
+
+uint8_t vtech_memexp_device::mreq_r(offs_t offset)
+{
+	return m_mem->read8(offset);
+}
+
+void vtech_memexp_device::mreq_w(offs_t offset, uint8_t data)
+{
+	m_mem->write8(offset, data);
+}
+
+uint8_t vtech_memexp_device::iorq_r(offs_t offset)
+{
+	return m_io->read8(offset);
+}
+
+void vtech_memexp_device::iorq_w(offs_t offset, uint8_t data)
+{
+	m_io->write8(offset, data);
+}
diff --git a/src/devices/bus/vtech/memexp/memexp.h b/src/devices/bus/vtech/memexp/memexp.h
index 28c7453be4a..a4ab93e92f7 100644
--- a/src/devices/bus/vtech/memexp/memexp.h
+++ b/src/devices/bus/vtech/memexp/memexp.h
@@ -1,5 +1,5 @@
-// license:GPL-2.0+
-// copyright-holders:Dirk Best
+// license: GPL-2.0+
+// copyright-holders: Dirk Best
 /***************************************************************************
 
     VTech Laser/VZ Memory Expansion Slot
@@ -36,9 +36,12 @@
 
 #pragma once
 
+#include "machine/bankdev.h"
+
 // include here so drivers don't need to
 #include "carts.h"
 
+
 //**************************************************************************
 //  TYPE DEFINITIONS
 //**************************************************************************
@@ -61,8 +64,8 @@ public:
 	vtech_memexp_slot_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock);
 	virtual ~vtech_memexp_slot_device();
 
-	template <typename T> void set_program_space(T &&tag, int spacenum) { m_program.set_tag(std::forward<T>(tag), spacenum); }
-	template <typename T> void set_io_space(T &&tag, int spacenum) { m_io.set_tag(std::forward<T>(tag), spacenum); }
+	template <typename T> void set_memspace(T &&tag, int spacenum) { m_memspace.set_tag(std::forward<T>(tag), spacenum); }
+	template <typename T> void set_iospace(T &&tag, int spacenum) { m_iospace.set_tag(std::forward<T>(tag), spacenum); }
 
 	// callbacks
 	auto int_handler() { return m_int_handler.bind(); }
@@ -76,16 +79,17 @@ public:
 
 protected:
 	// device-level overrides
-	virtual void device_config_complete() override;
 	virtual void device_start() override;
 
-	required_address_space m_program;
-	required_address_space m_io;
-
 private:
+	required_address_space m_memspace;
+	required_address_space m_iospace;
+
 	devcb_write_line m_int_handler;
 	devcb_write_line m_nmi_handler;
 	devcb_write_line m_reset_handler;
+
+	device_vtech_memexp_interface *m_module;
 };
 
 // class representing interface-specific live memexp device
@@ -96,13 +100,39 @@ public:
 	device_vtech_memexp_interface(const machine_config &mconfig, device_t &device);
 	virtual ~device_vtech_memexp_interface();
 
-protected:
-	address_space &program_space() { return *m_slot->m_program; }
-	address_space &io_space() { return *m_slot->m_io; }
+	virtual uint8_t mreq_r(offs_t offset) { return 0xff; }
+	virtual void mreq_w(offs_t offset, uint8_t data) { }
+	virtual uint8_t iorq_r(offs_t offset) { return 0xff; }
+	virtual void iorq_w(offs_t offset, uint8_t data) { }
 
+protected:
 	vtech_memexp_slot_device *m_slot;
 };
 
+// base memory expansion device
+class vtech_memexp_device : public device_t, public device_vtech_memexp_interface
+{
+public:
+	// construction/destruction
+	vtech_memexp_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, uint32_t clock);
+
+	// from host
+	virtual uint8_t mreq_r(offs_t offset) override;
+	virtual void mreq_w(offs_t offset, uint8_t data) override;
+	virtual uint8_t iorq_r(offs_t offset) override;
+	virtual void iorq_w(offs_t offset, uint8_t data) override;
+
+protected:
+	virtual void device_add_mconfig(machine_config &config) override;
+	virtual void device_start() override;
+
+	virtual void mem_map(address_map &map) { };
+	virtual void io_map(address_map &map) { };
+
+	required_device<address_map_bank_device> m_mem;
+	required_device<address_map_bank_device> m_io;
+};
+
 // device type definition
 DECLARE_DEVICE_TYPE(VTECH_MEMEXP_SLOT, vtech_memexp_slot_device)
 
diff --git a/src/devices/bus/vtech/memexp/memory.cpp b/src/devices/bus/vtech/memexp/memory.cpp
index 1b9465d9da9..bfac5f06b4c 100644
--- a/src/devices/bus/vtech/memexp/memory.cpp
+++ b/src/devices/bus/vtech/memexp/memory.cpp
@@ -24,13 +24,22 @@ DEFINE_DEVICE_TYPE(VTECH_LASER_64K,    vtech_laser_64k_device,    "vtech_laser_6
 //  LASER 110 16K DEVICE
 //**************************************************************************
 
+//-------------------------------------------------
+//  mem_map - memory space address map
+//-------------------------------------------------
+
+void vtech_laser110_16k_device::mem_map(address_map &map)
+{
+	map.unmap_value_high();
+	map(0x8000, 0xbfff).ram();
+}
+
 //-------------------------------------------------
 //  laser110_16k_device - constructor
 //-------------------------------------------------
 
 vtech_laser110_16k_device::vtech_laser110_16k_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) :
-	device_t(mconfig, VTECH_LASER110_16K, tag, owner, clock),
-	device_vtech_memexp_interface(mconfig, *this)
+	vtech_memexp_device(mconfig, VTECH_LASER110_16K, tag, owner, clock)
 {
 }
 
@@ -40,16 +49,7 @@ vtech_laser110_16k_device::vtech_laser110_16k_device(const machine_config &mconf
 
 void vtech_laser110_16k_device::device_start()
 {
-	m_ram.resize(16 * 1024);
-}
-
-//-------------------------------------------------
-//  device_reset - device-specific reset
-//-------------------------------------------------
-
-void vtech_laser110_16k_device::device_reset()
-{
-	program_space().install_ram(0x8000, 0xbfff, &m_ram[0]);
+	vtech_memexp_device::device_start();
 }
 
 
@@ -57,13 +57,22 @@ void vtech_laser110_16k_device::device_reset()
 //  LASER 210 16K DEVICE
 //**************************************************************************
 
+//-------------------------------------------------
+//  mem_map - memory space address map
+//-------------------------------------------------
+
+void vtech_laser210_16k_device::mem_map(address_map &map)
+{
+	map.unmap_value_high();
+	map(0x9000, 0xcfff).ram();
+}
+
 //-------------------------------------------------
 //  vtech_laser210_16k_device - constructor
 //-------------------------------------------------
 
 vtech_laser210_16k_device::vtech_laser210_16k_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) :
-	device_t(mconfig, VTECH_LASER210_16K, tag, owner, clock),
-	device_vtech_memexp_interface(mconfig, *this)
+	vtech_memexp_device(mconfig, VTECH_LASER210_16K, tag, owner, clock)
 {
 }
 
@@ -73,16 +82,7 @@ vtech_laser210_16k_device::vtech_laser210_16k_device(const machine_config &mconf
 
 void vtech_laser210_16k_device::device_start()
 {
-	m_ram.resize(16 * 1024);
-}
-
-//-------------------------------------------------
-//  device_reset - device-specific reset
-//-------------------------------------------------
-
-void vtech_laser210_16k_device::device_reset()
-{
-	program_space().install_ram(0x9000, 0xcfff, &m_ram[0]);
+	vtech_memexp_device::device_start();
 }
 
 
@@ -90,13 +90,22 @@ void vtech_laser210_16k_device::device_reset()
 //  VZ300 16K DEVICE
 //**************************************************************************
 
+//-------------------------------------------------
+//  mem_map - memory space address map
+//-------------------------------------------------
+
+void vtech_laser310_16k_device::mem_map(address_map &map)
+{
+	map.unmap_value_high();
+	map(0xb800, 0xf7ff).ram();
+}
+
 //-------------------------------------------------
 //  vtech_laser310_16k_device - constructor
 //-------------------------------------------------
 
 vtech_laser310_16k_device::vtech_laser310_16k_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) :
-	device_t(mconfig, VTECH_LASER310_16K, tag, owner, clock),
-	device_vtech_memexp_interface(mconfig, *this)
+	vtech_memexp_device(mconfig, VTECH_LASER310_16K, tag, owner, clock)
 {
 }
 
@@ -106,16 +115,7 @@ vtech_laser310_16k_device::vtech_laser310_16k_device(const machine_config &mconf
 
 void vtech_laser310_16k_device::device_start()
 {
-	m_ram.resize(16 * 1024);
-}
-
-//-------------------------------------------------
-//  device_reset - device-specific reset
-//-------------------------------------------------
-
-void vtech_laser310_16k_device::device_reset()
-{
-	program_space().install_ram(0xb800, 0xf7ff, &m_ram[0]);
+	vtech_memexp_device::device_start();
 }
 
 
@@ -123,13 +123,34 @@ void vtech_laser310_16k_device::device_reset()
 //  VZ300 64K DEVICE
 //**************************************************************************
 
+//-------------------------------------------------
+//  mem_map - memory space address map
+//-------------------------------------------------
+
+void vtech_laser_64k_device::mem_map(address_map &map)
+{
+	map.unmap_value_high();
+	map(0x8000, 0xbfff).bankrw(m_fixed_bank);
+	map(0xc000, 0xffff).bankrw(m_bank);
+}
+
+//-------------------------------------------------
+//  io_map - memory space address map
+//-------------------------------------------------
+
+void vtech_laser_64k_device::io_map(address_map &map)
+{
+	map.unmap_value_high();
+	map(0x70, 0x70).mirror(0x0f).lw8(NAME([this] (uint8_t data) { m_bank->set_entry(data & 0x03); }));
+}
+
 //-------------------------------------------------
 //  vtech_laser_64k_device - constructor
 //-------------------------------------------------
 
 vtech_laser_64k_device::vtech_laser_64k_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) :
-	device_t(mconfig, VTECH_LASER_64K, tag, owner, clock),
-	device_vtech_memexp_interface(mconfig, *this),
+	vtech_memexp_device(mconfig, VTECH_LASER_64K, tag, owner, clock),
+	m_fixed_bank(*this, "fixed_bank"),
 	m_bank(*this, "bank")
 {
 }
@@ -140,29 +161,17 @@ vtech_laser_64k_device::vtech_laser_64k_device(const machine_config &mconfig, co
 
 void vtech_laser_64k_device::device_start()
 {
-	m_ram.resize(64 * 1024);
-}
+	vtech_memexp_device::device_start();
 
-//-------------------------------------------------
-//  device_reset - device-specific reset
-//-------------------------------------------------
+	// init ram
+	m_ram = std::make_unique<uint8_t[]>(0x10000);
 
-void vtech_laser_64k_device::device_reset()
-{
-	// fixed first bank
-	program_space().install_ram(0x8000, 0xbfff, &m_ram[0]);
+	// configure banking
+	m_fixed_bank->set_base(m_ram.get());
 
-	// other banks
-	program_space().install_readwrite_bank(0xc000, 0xffff, m_bank);
-
-	m_bank->configure_entries(0, 4, &m_ram[0], 0x4000);
+	m_bank->configure_entries(0, 4, m_ram.get(), 0x4000);
 	m_bank->set_entry(1);
 
-	// bank switch
-	io_space().install_write_handler(0x70, 0x7f, write8smo_delegate(*this, FUNC(vtech_laser_64k_device::bankswitch_w)));
-}
-
-void vtech_laser_64k_device::bankswitch_w(uint8_t data)
-{
-	m_bank->set_entry(data & 0x03);
+	// register for savestates
+	save_pointer(NAME(m_ram), 0x10000);
 }
diff --git a/src/devices/bus/vtech/memexp/memory.h b/src/devices/bus/vtech/memexp/memory.h
index 84c3952fb67..5af19fd27f1 100644
--- a/src/devices/bus/vtech/memexp/memory.h
+++ b/src/devices/bus/vtech/memexp/memory.h
@@ -20,7 +20,7 @@
 
 // ======================> vtech_laser110_16k_device
 
-class vtech_laser110_16k_device : public device_t, public device_vtech_memexp_interface
+class vtech_laser110_16k_device : public vtech_memexp_device
 {
 public:
 	// construction/destruction
@@ -28,15 +28,13 @@ public:
 
 protected:
 	virtual void device_start() override;
-	virtual void device_reset() override;
 
-private:
-	std::vector<uint8_t> m_ram;
+	virtual void mem_map(address_map &map) override;
 };
 
 // ======================> vtech_laser210_16k_device
 
-class vtech_laser210_16k_device : public device_t, public device_vtech_memexp_interface
+class vtech_laser210_16k_device : public vtech_memexp_device
 {
 public:
 	// construction/destruction
@@ -44,15 +42,13 @@ public:
 
 protected:
 	virtual void device_start() override;
-	virtual void device_reset() override;
 
-private:
-	std::vector<uint8_t> m_ram;
+	virtual void mem_map(address_map &map) override;
 };
 
 // ======================> vtech_laser310_16k_device
 
-class vtech_laser310_16k_device : public device_t, public device_vtech_memexp_interface
+class vtech_laser310_16k_device : public vtech_memexp_device
 {
 public:
 	// construction/destruction
@@ -60,29 +56,29 @@ public:
 
 protected:
 	virtual void device_start() override;
-	virtual void device_reset() override;
 
-private:
-	std::vector<uint8_t> m_ram;
+	virtual void mem_map(address_map &map) override;
 };
 
 // ======================> vtech_laser_64k_device
 
-class vtech_laser_64k_device : public device_t, public device_vtech_memexp_interface
+class vtech_laser_64k_device : public vtech_memexp_device
 {
 public:
 	// construction/destruction
 	vtech_laser_64k_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock);
 
-	void bankswitch_w(uint8_t data);
-
 protected:
 	virtual void device_start() override;
-	virtual void device_reset() override;
+
+	virtual void mem_map(address_map &map) override;
+	virtual void io_map(address_map &map) override;
 
 private:
-	memory_bank_creator m_bank;
-	std::vector<uint8_t> m_ram;
+	required_memory_bank m_fixed_bank;
+	required_memory_bank m_bank;
+
+	std::unique_ptr<uint8_t[]> m_ram;
 };
 
 // device type definition
diff --git a/src/devices/bus/vtech/memexp/rs232.cpp b/src/devices/bus/vtech/memexp/rs232.cpp
index 028e9502b37..cf07b2055d6 100644
--- a/src/devices/bus/vtech/memexp/rs232.cpp
+++ b/src/devices/bus/vtech/memexp/rs232.cpp
@@ -16,6 +16,18 @@
 
 DEFINE_DEVICE_TYPE(VTECH_RS232_INTERFACE, vtech_rs232_interface_device, "vtech_rs232", "DSE VZ-200/300 RS-232 Interface")
 
+//-------------------------------------------------
+//  mem_map - memory space address map
+//-------------------------------------------------
+
+void vtech_rs232_interface_device::mem_map(address_map &map)
+{
+	map.unmap_value_high();
+	map(0x4000, 0x47ff).rom().region("software", 0);
+	map(0x5000, 0x5000).mirror(0x7ff).r(FUNC(vtech_rs232_interface_device::receive_data_r));
+	map(0x5800, 0x5800).mirror(0x7ff).w(FUNC(vtech_rs232_interface_device::transmit_data_w));
+}
+
 //-------------------------------------------------
 //  rom_region - device-specific ROM region
 //-------------------------------------------------
@@ -40,8 +52,10 @@ const tiny_rom_entry *vtech_rs232_interface_device::device_rom_region() const
 
 void vtech_rs232_interface_device::device_add_mconfig(machine_config &config)
 {
+	vtech_memexp_device::device_add_mconfig(config);
+
 	RS232_PORT(config, m_rs232, default_rs232_devices, nullptr);
-	m_rs232->rxd_handler().set(FUNC(vtech_rs232_interface_device::rs232_rx_w));
+	m_rs232->rxd_handler().set([this](int state) { m_rx = state; });
 }
 
 
@@ -54,8 +68,7 @@ void vtech_rs232_interface_device::device_add_mconfig(machine_config &config)
 //-------------------------------------------------
 
 vtech_rs232_interface_device::vtech_rs232_interface_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) :
-	device_t(mconfig, VTECH_RS232_INTERFACE, tag, owner, clock),
-	device_vtech_memexp_interface(mconfig, *this),
+	vtech_memexp_device(mconfig, VTECH_RS232_INTERFACE, tag, owner, clock),
 	m_rs232(*this, "rs232"),
 	m_rx(1)
 {
@@ -67,20 +80,10 @@ vtech_rs232_interface_device::vtech_rs232_interface_device(const machine_config
 
 void vtech_rs232_interface_device::device_start()
 {
-}
+	vtech_memexp_device::device_start();
 
-//-------------------------------------------------
-//  device_reset - device-specific reset
-//-------------------------------------------------
-
-void vtech_rs232_interface_device::device_reset()
-{
-	// program
-	program_space().install_rom(0x4000, 0x47ff, 0x800, memregion("software")->base());
-
-	// data
-	program_space().install_read_handler(0x5000, 0x57ff, read8smo_delegate(*this, FUNC(vtech_rs232_interface_device::receive_data_r)));
-	program_space().install_write_handler(0x5800, 0x5fff, write8smo_delegate(*this, FUNC(vtech_rs232_interface_device::transmit_data_w)));
+	// register for save states
+	save_item(NAME(m_rx));
 }
 
 
@@ -88,11 +91,6 @@ void vtech_rs232_interface_device::device_reset()
 //  IMPLEMENTATION
 //**************************************************************************
 
-WRITE_LINE_MEMBER( vtech_rs232_interface_device::rs232_rx_w )
-{
-	m_rx = state;
-}
-
 uint8_t vtech_rs232_interface_device::receive_data_r()
 {
 	return 0x7f | (m_rx << 7);
diff --git a/src/devices/bus/vtech/memexp/rs232.h b/src/devices/bus/vtech/memexp/rs232.h
index 25094dcc7a2..d713aec9151 100644
--- a/src/devices/bus/vtech/memexp/rs232.h
+++ b/src/devices/bus/vtech/memexp/rs232.h
@@ -21,7 +21,7 @@
 
 // ======================> vtech_rs232_interface_device
 
-class vtech_rs232_interface_device : public device_t, public device_vtech_memexp_interface
+class vtech_rs232_interface_device : public vtech_memexp_device
 {
 public:
 	// construction/destruction
@@ -31,15 +31,15 @@ protected:
 	virtual const tiny_rom_entry *device_rom_region() const override;
 	virtual void device_add_mconfig(machine_config &config) override;
 	virtual void device_start() override;
-	virtual void device_reset() override;
+
+	virtual void mem_map(address_map &map) override;
 
 private:
-	DECLARE_WRITE_LINE_MEMBER( rs232_rx_w );
+	required_device<rs232_port_device> m_rs232;
+	
 	uint8_t receive_data_r();
 	void transmit_data_w(uint8_t data);
-
-	required_device<rs232_port_device> m_rs232;
-
+	
 	int m_rx;
 };
 
diff --git a/src/devices/bus/vtech/memexp/rtty.cpp b/src/devices/bus/vtech/memexp/rtty.cpp
index 6830ff14c13..6a0f96c58a8 100644
--- a/src/devices/bus/vtech/memexp/rtty.cpp
+++ b/src/devices/bus/vtech/memexp/rtty.cpp
@@ -16,6 +16,19 @@
 
 DEFINE_DEVICE_TYPE(VTECH_RTTY_INTERFACE, vtech_rtty_interface_device, "vtech_rtty", "DSE VZ-200/300 RTTY Interface")
 
+//-------------------------------------------------
+//  mem_map - memory space address map
+//-------------------------------------------------
+
+void vtech_rtty_interface_device::mem_map(address_map &map)
+{
+	map.unmap_value_high();
+	map(0x4000, 0x4fff).rom().region("software", 0);
+	map(0x5000, 0x5000).mirror(0x7ff).r(FUNC(vtech_rtty_interface_device::receive_data_r));
+	map(0x5800, 0x5800).mirror(0x7ff).w(FUNC(vtech_rtty_interface_device::transmit_data_w));
+	map(0x6000, 0x6000).mirror(0x7ff).w(FUNC(vtech_rtty_interface_device::relay_w));
+}
+
 //-------------------------------------------------
 //  rom_region - device-specific ROM region
 //-------------------------------------------------
@@ -40,8 +53,7 @@ const tiny_rom_entry *vtech_rtty_interface_device::device_rom_region() const
 //-------------------------------------------------
 
 vtech_rtty_interface_device::vtech_rtty_interface_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) :
-	device_t(mconfig, VTECH_RTTY_INTERFACE, tag, owner, clock),
-	device_vtech_memexp_interface(mconfig, *this)
+	vtech_memexp_device(mconfig, VTECH_RTTY_INTERFACE, tag, owner, clock)
 {
 }
 
@@ -51,21 +63,7 @@ vtech_rtty_interface_device::vtech_rtty_interface_device(const machine_config &m
 
 void vtech_rtty_interface_device::device_start()
 {
-}
-
-//-------------------------------------------------
-//  device_reset - device-specific reset
-//-------------------------------------------------
-
-void vtech_rtty_interface_device::device_reset()
-{
-	// program
-	program_space().install_rom(0x4000, 0x4fff, 0x1000, memregion("software")->base());
-
-	// data
-	program_space().install_read_handler(0x5000, 0x57ff, read8smo_delegate(*this, FUNC(vtech_rtty_interface_device::receive_data_r)));
-	program_space().install_write_handler(0x5800, 0x5fff, write8smo_delegate(*this, FUNC(vtech_rtty_interface_device::transmit_data_w)));
-	program_space().install_write_handler(0x6000, 0x67ff, write8smo_delegate(*this, FUNC(vtech_rtty_interface_device::relay_w)));
+	vtech_memexp_device::device_start();
 }
 
 
diff --git a/src/devices/bus/vtech/memexp/rtty.h b/src/devices/bus/vtech/memexp/rtty.h
index 9868bef9bee..62d1f5b94af 100644
--- a/src/devices/bus/vtech/memexp/rtty.h
+++ b/src/devices/bus/vtech/memexp/rtty.h
@@ -20,20 +20,22 @@
 
 // ======================> vtech_rtty_interface_device
 
-class vtech_rtty_interface_device : public device_t, public device_vtech_memexp_interface
+class vtech_rtty_interface_device : public vtech_memexp_device
 {
 public:
 	// construction/destruction
 	vtech_rtty_interface_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock);
 
-	uint8_t receive_data_r();
-	void transmit_data_w(uint8_t data);
-	void relay_w(uint8_t data);
-
 protected:
 	virtual const tiny_rom_entry *device_rom_region() const override;
 	virtual void device_start() override;
-	virtual void device_reset() override;
+
+	virtual void mem_map(address_map &map) override;
+
+private:
+	uint8_t receive_data_r();
+	void transmit_data_w(uint8_t data);
+	void relay_w(uint8_t data);
 };
 
 // device type definition
diff --git a/src/devices/bus/vtech/memexp/sdloader.cpp b/src/devices/bus/vtech/memexp/sdloader.cpp
new file mode 100644
index 00000000000..f20c19ebbc8
--- /dev/null
+++ b/src/devices/bus/vtech/memexp/sdloader.cpp
@@ -0,0 +1,180 @@
+// license: GPL-2.0+
+// copyright-holders: Dirk Best
+/***************************************************************************
+
+    BennVenn SD Loader for VZ300
+
+    Notes:
+    - Also works for VZ200
+
+    TODO:
+    - No SD card emulation, so only the memory expansion part works
+
+***************************************************************************/
+
+#include "emu.h"
+#include "sdloader.h"
+
+
+//**************************************************************************
+//  DEVICE DEFINITIONS
+//**************************************************************************
+
+DEFINE_DEVICE_TYPE(VTECH_SDLOADER, vtech_sdloader_device, "vtech_sdloader", "BennVenn SD Loader")
+
+//-------------------------------------------------
+//  mem_map - memory space address map
+//-------------------------------------------------
+
+void vtech_sdloader_device::mem_map(address_map &map)
+{
+	map.unmap_value_high();
+	map(0x4000, 0x67ff).view(m_dosview);
+	m_dosview[0](0x4000, 0x67ff).rom().region("software", 0).bankw(m_dosbank);
+	m_dosview[1](0x4000, 0x67ff).bankrw(m_dosbank);
+	map(0x9000, 0xffff).rw(FUNC(vtech_sdloader_device::exp_ram_r), FUNC(vtech_sdloader_device::exp_ram_w));
+}
+
+//-------------------------------------------------
+//  io_map - io space address map
+//-------------------------------------------------
+
+void vtech_sdloader_device::io_map(address_map &map)
+{
+	map.unmap_value_high();
+	map(0x37, 0x37).w(FUNC(vtech_sdloader_device::mapper_w));
+	map(0x38, 0x38).w(FUNC(vtech_sdloader_device::sdcfg_w));
+	map(0x39, 0x39).rw(FUNC(vtech_sdloader_device::sdio_r), FUNC(vtech_sdloader_device::sdio_w));
+	map(0x3a, 0x3a).w(FUNC(vtech_sdloader_device::mode_w));
+}
+
+//-------------------------------------------------
+//  rom_region - device-specific ROM region
+//-------------------------------------------------
+
+ROM_START( sdloader )
+	ROM_REGION(0x2800, "software", 0)
+	ROM_DEFAULT_BIOS("18")
+	ROM_SYSTEM_BIOS(0, "15", "Version 1.5")
+	ROMX_LOAD("vzdos15.bin", 0x0000, 0x16c2, CRC(828f7703) SHA1(150c6e5a8f20416c0dab1fa96f68726f415a8b7e), ROM_BIOS(0))
+	ROM_SYSTEM_BIOS(1, "17", "Version 1.7")
+	ROMX_LOAD("vzdos17.bin", 0x0000, 0x1783, CRC(7ef7fb1e) SHA1(6278ac675d6c08dca39a5a7f4c72988a178eff8a), ROM_BIOS(1))
+	ROM_SYSTEM_BIOS(2, "18", "Version 1.8")
+	ROMX_LOAD("vzdos18.bin", 0x0000, 0x1795, CRC(2b1cec28) SHA1(d4f8fa0c7a70984334be3e5c831017cfc53683b2), ROM_BIOS(2))
+ROM_END
+
+const tiny_rom_entry *vtech_sdloader_device::device_rom_region() const
+{
+	return ROM_NAME( sdloader );
+}
+
+
+//**************************************************************************
+//  LIVE DEVICE
+//**************************************************************************
+
+//-------------------------------------------------
+//  vtech_sdloader_device - constructor
+//-------------------------------------------------
+
+vtech_sdloader_device::vtech_sdloader_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) :
+	vtech_memexp_device(mconfig, VTECH_SDLOADER, tag, owner, clock),
+	m_dosbank(*this, "dosbank"),
+	m_dosview(*this, "dosview"),
+	m_expbank(*this, "expbank"),
+	m_vz300_mode(false)
+{
+}
+
+//-------------------------------------------------
+//  device_start - device-specific startup
+//-------------------------------------------------
+
+void vtech_sdloader_device::device_start()
+{
+	vtech_memexp_device::device_start();
+
+	// init ram
+	m_ram = std::make_unique<uint8_t[]>(0x20000);
+
+	// configure banks
+	m_dosbank->configure_entry(0, m_ram.get() + 0x00000);
+	m_dosbank->configure_entry(1, m_ram.get() + 0x08000);
+	m_expbank->configure_entry(0, m_ram.get() + 0x10000);
+	m_expbank->configure_entry(1, m_ram.get() + 0x18000);
+
+	// register for savestates
+	save_item(NAME(m_vz300_mode));
+	save_pointer(NAME(m_ram), 0x20000);
+}
+
+//-------------------------------------------------
+//  device_reset - device-specific startup
+//-------------------------------------------------
+
+void vtech_sdloader_device::device_reset()
+{
+	// startup in vz200 mode
+	m_vz300_mode = false;
+
+	// rom enabled
+	m_dosview.select(0);
+}
+
+
+//**************************************************************************
+//  IMPLEMENTATION
+//**************************************************************************
+
+void vtech_sdloader_device::mapper_w(uint8_t data)
+{
+	// 7654----  not used
+	// ----3---  led
+	// -----2--  expansion ram bank
+	// ------1-  dos ram bank
+	// -------0  dos rom/ram switch
+
+	m_dosview.select(BIT(data, 0));
+	m_dosbank->set_entry(BIT(data, 1));
+	m_expbank->set_entry(BIT(data, 2));
+}
+
+void vtech_sdloader_device::sdcfg_w(uint8_t data)
+{
+	logerror("sdcfg_w: %02x\n", data);
+}
+
+uint8_t vtech_sdloader_device::sdio_r()
+{
+	logerror("sdio_r\n");
+	return 0xff;
+}
+
+void vtech_sdloader_device::sdio_w(uint8_t data)
+{
+	logerror("sdio_w: %02x\n", data);
+}
+
+void vtech_sdloader_device::mode_w(uint8_t data)
+{
+	logerror("Switching to %s mode\n", BIT(data, 0) ? "VZ-300" : "VZ-200");
+	m_vz300_mode = bool(BIT(data, 0));
+}
+
+uint8_t vtech_sdloader_device::exp_ram_r(offs_t offset)
+{
+	offset += 0x9000;
+
+	if (!m_vz300_mode || (m_vz300_mode && offset >= 0xb800))
+		return reinterpret_cast<uint8_t *>(m_expbank->base())[offset & 0x7fff];
+
+	return 0xff;
+}
+
+void vtech_sdloader_device::exp_ram_w(offs_t offset, uint8_t data)
+{
+	offset += 0x9000;
+
+	if (!m_vz300_mode || (m_vz300_mode && offset >= 0xb800))
+		reinterpret_cast<uint8_t *>(m_expbank->base())[offset & 0x7fff] = data;
+}
diff --git a/src/devices/bus/vtech/memexp/sdloader.h b/src/devices/bus/vtech/memexp/sdloader.h
new file mode 100644
index 00000000000..e2c80302ef6
--- /dev/null
+++ b/src/devices/bus/vtech/memexp/sdloader.h
@@ -0,0 +1,60 @@
+// license: GPL-2.0+
+// copyright-holders: Dirk Best
+/***************************************************************************
+
+    BennVenn SD Loader for VZ300
+
+***************************************************************************/
+
+#ifndef MAME_BUS_VTECH_MEMEXP_SDLOADER_H
+#define MAME_BUS_VTECH_MEMEXP_SDLOADER_H
+
+#pragma once
+
+#include "memexp.h"
+
+
+//**************************************************************************
+//  TYPE DEFINITIONS
+//**************************************************************************
+
+// ======================> vtech_sdloader_device
+
+class vtech_sdloader_device : public vtech_memexp_device
+{
+public:
+	// construction/destruction
+	vtech_sdloader_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock);
+
+	static constexpr feature_type unemulated_features() { return feature::DISK; }
+
+protected:
+	virtual const tiny_rom_entry *device_rom_region() const override;
+	virtual void device_start() override;
+	virtual void device_reset() override;
+
+	virtual void mem_map(address_map &map) override;
+	virtual void io_map(address_map &map) override;
+
+private:
+	required_memory_bank m_dosbank;
+	memory_view m_dosview;
+	memory_bank_creator m_expbank;
+
+	void mapper_w(uint8_t data);
+	void sdcfg_w(uint8_t data);
+	uint8_t sdio_r();
+	void sdio_w(uint8_t data);
+	void mode_w(uint8_t data);
+
+	uint8_t exp_ram_r(offs_t offset);
+	void exp_ram_w(offs_t offset, uint8_t data);
+
+	std::unique_ptr<uint8_t[]> m_ram;
+	bool m_vz300_mode;
+};
+
+// device type definition
+DECLARE_DEVICE_TYPE(VTECH_SDLOADER, vtech_sdloader_device)
+
+#endif // MAME_BUS_VTECH_MEMEXP_SDLOADER_H
diff --git a/src/devices/bus/vtech/memexp/wordpro.cpp b/src/devices/bus/vtech/memexp/wordpro.cpp
index 099702ef844..811cb953a83 100644
--- a/src/devices/bus/vtech/memexp/wordpro.cpp
+++ b/src/devices/bus/vtech/memexp/wordpro.cpp
@@ -16,6 +16,17 @@
 
 DEFINE_DEVICE_TYPE(VTECH_WORDPRO, vtech_wordpro_device, "vtech_wordpro", "DSE VZ-300 WordPro")
 
+//-------------------------------------------------
+//  mem_map - memory space address map
+//-------------------------------------------------
+
+void vtech_wordpro_device::mem_map(address_map &map)
+{
+	map.unmap_value_high();
+	map(0x6000, 0x67ff).rom().region("software", 0);
+	map(0xd000, 0xffff).rom().region("software", 0);
+}
+
 //-------------------------------------------------
 //  rom_region - device-specific ROM region
 //-------------------------------------------------
@@ -42,8 +53,7 @@ const tiny_rom_entry *vtech_wordpro_device::device_rom_region() const
 //-------------------------------------------------
 
 vtech_wordpro_device::vtech_wordpro_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) :
-	device_t(mconfig, VTECH_WORDPRO, tag, owner, clock),
-	device_vtech_memexp_interface(mconfig, *this)
+	vtech_memexp_device(mconfig, VTECH_WORDPRO, tag, owner, clock)
 {
 }
 
@@ -53,14 +63,5 @@ vtech_wordpro_device::vtech_wordpro_device(const machine_config &mconfig, const
 
 void vtech_wordpro_device::device_start()
 {
-}
-
-//-------------------------------------------------
-//  device_reset - device-specific reset
-//-------------------------------------------------
-
-void vtech_wordpro_device::device_reset()
-{
-	program_space().install_rom(0x6000, 0x67ff, memregion("software")->base());
-	program_space().install_rom(0xd000, 0xffff, memregion("software")->base());
+	vtech_memexp_device::device_start();
 }
diff --git a/src/devices/bus/vtech/memexp/wordpro.h b/src/devices/bus/vtech/memexp/wordpro.h
index f7b6422a319..0515a12bb36 100644
--- a/src/devices/bus/vtech/memexp/wordpro.h
+++ b/src/devices/bus/vtech/memexp/wordpro.h
@@ -20,7 +20,7 @@
 
 // ======================> vtech_wordpro_device
 
-class vtech_wordpro_device : public device_t, public device_vtech_memexp_interface
+class vtech_wordpro_device : public vtech_memexp_device
 {
 public:
 	// construction/destruction
@@ -29,7 +29,8 @@ public:
 protected:
 	virtual const tiny_rom_entry *device_rom_region() const override;
 	virtual void device_start() override;
-	virtual void device_reset() override;
+
+	virtual void mem_map(address_map &map) override;
 };
 
 // device type definition
diff --git a/src/mame/drivers/vtech1.cpp b/src/mame/drivers/vtech1.cpp
index 55abef9afa5..2352f586c2e 100644
--- a/src/mame/drivers/vtech1.cpp
+++ b/src/mame/drivers/vtech1.cpp
@@ -95,7 +95,6 @@ protected:
 
 	DECLARE_SNAPSHOT_LOAD_MEMBER(snapshot_cb);
 
-	uint8_t lightpen_r(offs_t offset);
 	uint8_t keyboard_r(offs_t offset);
 	virtual void latch_w(uint8_t data);
 	uint8_t vram_r(memory_share_creator<uint8_t> &vram, offs_t offset);
@@ -228,12 +227,6 @@ SNAPSHOT_LOAD_MEMBER(vtech1_base_state::snapshot_cb)
     INPUTS
 ***************************************************************************/
 
-uint8_t vtech1_base_state::lightpen_r(offs_t offset)
-{
-	logerror("vtech1_lightpen_r(%d)\n", offset);
-	return 0xff;
-}
-
 uint8_t vtech1_base_state::keyboard_r(offs_t offset)
 {
 	uint8_t result = 0x3f;
@@ -340,10 +333,13 @@ void laser310h_state::machine_start()
 
 void vtech1_base_state::laser110_mem(address_map &map)
 {
+	map.unmap_value_high();
 	map(0x0000, 0x3fff).rom(); // basic rom
+	map(0x4000, 0x67ff).noprw(); // cartridge space
 	map(0x6800, 0x6fff).rw(FUNC(vtech1_base_state::keyboard_r), FUNC(vtech1_base_state::latch_w));
 	map(0x7000, 0x77ff).bankrw("vbank");
 	map(0x7800, 0x7fff).ram(); // 2k user ram
+	map(0x8000, 0xffff).noprw(); // expansion ram
 }
 
 void vtech1_base_state::laser210_mem(address_map &map)
@@ -360,8 +356,9 @@ void vtech1_base_state::laser310_mem(address_map &map)
 
 void vtech1_base_state::vtech1_io(address_map &map)
 {
+	map.unmap_value_high();
 	map.global_mask(0xff);
-	map(0x40, 0x4f).r(FUNC(vtech1_base_state::lightpen_r));
+	map(0x00, 0xff).noprw(); // completely handled by expansion devices
 }
 
 void laser310h_state::vtech1_shrg_mem(address_map &map)
@@ -479,11 +476,11 @@ void vtech1_base_state::vtech1(machine_config &config)
 
 	// peripheral and memory expansion slots
 	VTECH_IOEXP_SLOT(config, m_ioexp);
-	m_ioexp->set_io_space(m_maincpu, AS_IO);
+	m_ioexp->set_iospace(m_maincpu, AS_IO);
 
 	VTECH_MEMEXP_SLOT(config, m_memexp);
-	m_memexp->set_program_space(m_maincpu, AS_PROGRAM);
-	m_memexp->set_io_space(m_maincpu, AS_IO);
+	m_memexp->set_memspace(m_maincpu, AS_PROGRAM);
+	m_memexp->set_iospace(m_maincpu, AS_IO);
 
 	// snapshot
 	snapshot_image_device &snapshot(SNAPSHOT(config, "snapshot", "vz"));
diff --git a/src/mame/drivers/vtech2.cpp b/src/mame/drivers/vtech2.cpp
index c55bb04aee8..187bf8f86fd 100644
--- a/src/mame/drivers/vtech2.cpp
+++ b/src/mame/drivers/vtech2.cpp
@@ -92,6 +92,8 @@ void vtech2_state::mem_map(address_map &map)
 void vtech2_state::io_map(address_map &map)
 {
 	map.global_mask(0xff);
+	map.unmap_value_high();
+	map(0x00, 0xff).noprw();
 	map(0x10, 0x1f).rw(FUNC(vtech2_state::laser_fdc_r), FUNC(vtech2_state::laser_fdc_w));
 	map(0x40, 0x40).lw8(NAME([this] (u8 data) { m_banka->set_bank(data & 15); }));
 	map(0x41, 0x41).lw8(NAME([this] (u8 data) { m_bankb->set_bank(data & 15); }));
@@ -494,7 +496,8 @@ void vtech2_state::laser350(machine_config &config)
 	m_cassette->set_default_state(CASSETTE_STOPPED);
 	m_cassette->add_route(ALL_OUTPUTS, "mono", 0.05);
 
-	VTECH_IOEXP_SLOT(config, "io").set_io_space(m_maincpu, AS_IO);
+	VTECH_IOEXP_SLOT(config, m_ioexp);
+	m_ioexp->set_iospace(m_maincpu, AS_IO);
 
 	/* cartridge */
 	GENERIC_CARTSLOT(config, "cartslot", generic_plain_slot, "vtech_cart", "rom,bin").set_device_load(FUNC(vtech2_state::cart_load));