diff --git a/src/mame/mame.lst b/src/mame/mame.lst
index 6ad892c3423..8e94fdd8ed3 100644
--- a/src/mame/mame.lst
+++ b/src/mame/mame.lst
@@ -29800,6 +29800,9 @@ cjmx
 crzclass
 ddz
 
+@source:misc/deecoseal.cpp
+deecoseal
+
 @source:misc/dfruit.cpp
 dfruit
 dfruita
diff --git a/src/mame/misc/deecoseal.cpp b/src/mame/misc/deecoseal.cpp
new file mode 100644
index 00000000000..04455ea0331
--- /dev/null
+++ b/src/mame/misc/deecoseal.cpp
@@ -0,0 +1,133 @@
+// license:BSD-3-Clause
+// copyright-holders:Carl
+/***************************************************************************
+
+    Lucas Deeco SealTouch
+
+***************************************************************************/
+
+#include "emu.h"
+#include "cpu/i86/i186.h"
+#include "cpu/mcs51/mcs51.h"
+#include "screen.h"
+#include "video/upd7220.h"
+#include "bus/rs232/rs232.h"
+#include "machine/mc68681.h"
+#include "machine/i2cmem.h"
+
+namespace {
+
+class deecoseal_state : public driver_device
+{
+public:
+	deecoseal_state(const machine_config &mconfig, device_type type, const char *tag) :
+		driver_device(mconfig, type, tag),
+		m_maincpu(*this, "maincpu"),
+		m_mcs51(*this, "mcs51"),
+		m_crtc(*this, "crtc"),
+		m_duart(*this, "duart")
+	{ }
+
+	void deecoseal(machine_config &config);
+
+private:
+	virtual void machine_start() override ATTR_COLD;
+	void map(address_map &map);
+	void io(address_map &map);
+	void mcs51_map(address_map &map);
+	void crtc_map(address_map &map);
+
+	bool m_port0;
+
+	required_device<i80186_cpu_device> m_maincpu;
+	required_device<cpu_device> m_mcs51;
+	required_device<upd7220_device> m_crtc;
+	required_device<scn2681_device> m_duart;
+};
+
+void deecoseal_state::machine_start()
+{
+	u16 *rom = (u16 *)memregion("bios")->base();
+	u16 swapbuf[128];
+
+	for(int i = 0; i < 32768; i += 128)
+	{
+		u16 *cur = rom + i;
+		memcpy(swapbuf, cur, 256);
+		for(int j = 0; j < 128; j++)
+		{
+			int addr = 0;
+			addr |= ((BIT(j, 3) & !BIT(j, 5)) | (BIT(j, 4) & BIT(j, 5)));
+			addr |= ((BIT(j, 3) & BIT(j, 5)) | (BIT(j, 4) & !BIT(j, 5))) << 1;
+			addr |= ((BIT(j, 0) & BIT(j, 6)) | (BIT(j, 5) & !BIT(j, 6))) << 2;
+			addr |= ((BIT(j, 0) & !BIT(j, 6)) | (BIT(j, 5) & BIT(j, 6))) << 3;
+			addr |= BIT(j, 6) << 4;
+			addr |= ((BIT(j, 1) & !BIT(j, 4)) | (BIT(j, 2) & BIT(j, 4))) << 5;
+			addr |= ((BIT(j, 1) & BIT(j, 4)) | (BIT(j, 2) & !BIT(j, 4))) << 6;
+			cur[j] = swapbuf[addr];
+		}
+	}
+
+	m_port0 = false;
+}
+
+void deecoseal_state::map(address_map &map)
+{
+	map(0x00000, 0x0ffff).ram();
+	map(0x40000, 0x43fff).ram();
+	map(0xf0000, 0xfffff).rom().region("bios", 0);
+}
+
+void deecoseal_state::io(address_map &map)
+{
+	map(0x0000, 0x0001).lr16([this](){ m_port0 = !m_port0; return m_port0 ? 0x10 : 0; }, "port0");
+	map(0x0110, 0x011f).rw(m_duart, FUNC(scn2681_device::read), FUNC(scn2681_device::write)).umask16(0x00ff);
+	map(0x0180, 0x0183).rw(m_crtc, FUNC(upd7220_device::read), FUNC(upd7220_device::write)).umask16(0x00ff);
+}
+
+void deecoseal_state::mcs51_map(address_map &map)
+{
+	map(0x0000, 0x7fff).rom().region("mcs51", 0);
+}
+
+void deecoseal_state::crtc_map(address_map &map)
+{
+	map(0x0000, 0x7fff).ram();
+}
+
+void deecoseal_state::deecoseal(machine_config &config)
+{
+	I80186(config, m_maincpu, XTAL(24'000'000));
+	m_maincpu->set_addrmap(AS_PROGRAM, &deecoseal_state::map);
+	m_maincpu->set_addrmap(AS_IO, &deecoseal_state::io);
+
+	I80C31(config, m_mcs51, XTAL(24'000'000) / 4); // clock?
+	m_mcs51->set_addrmap(AS_PROGRAM, &deecoseal_state::mcs51_map);
+
+	I2C_X2404P(config, "eeprom");
+
+	UPD7220(config, m_crtc, XTAL(16'257'000) / 2); // unknown clock
+	m_crtc->set_addrmap(AS_PROGRAM, &deecoseal_state::crtc_map);
+	m_crtc->set_screen("screen");
+
+	SCN2681(config, m_duart, XTAL(3'686'400)); // scn2692
+
+	screen_device &screen(SCREEN(config, "screen", SCREEN_TYPE_RASTER));
+	screen.set_raw(XTAL(16'257'000), 848, 0, 640, 440, 0, 400);
+	screen.set_screen_update(m_crtc, FUNC(upd7220_device::screen_update));
+}
+
+ROM_START(deecoseal)
+	ROM_REGION16_LE(0x10000, "bios", 0)
+	ROM_SYSTEM_BIOS(0, "bios", "bios")
+	ROMX_LOAD("u28_27256_lo_rev_k_lucas_1990.bin", 0x0000, 0x8000, CRC(4f5e0d47) SHA1(646e369464b66705dbab888c8f351121ffc4bc37), ROM_SKIP(1) | ROM_BIOS(0))
+	ROMX_LOAD("u10_27256_hi_rev_k_lucas_1990.bin", 0x0001, 0x8000, CRC(20f7d631) SHA1(797482bc6b4427b8bf750608c5a83185fae02405), ROM_SKIP(1) | ROM_BIOS(0))
+
+	ROM_REGION(0x8000, "mcs51", 0)
+	ROM_LOAD("u34_27256_rev_b_lucas_1989.bin", 0x0000, 0x8000, CRC(01574116) SHA1(75d8dc739bf4ef1db91341f2fb02e0c698e39536))
+ROM_END
+
+} // anonymous namespace
+
+
+COMP(1990, deecoseal, 0, 0, deecoseal, 0, deecoseal_state, empty_init, "Lucas", "Deeco SealTouch ST3220", MACHINE_NOT_WORKING | MACHINE_NO_SOUND)