mbc55x: Various additions and refinements

- Correct all clocks and derive them from the master XTAL
- Correct I/O address decoding
- Enable speaker output from 8251 USART
- Add ISA expansion slot, Centronics printer and RS232 "line" ports
- Add backspace key to HLE keyboard and note undumped MCU

src/mame/drivers/mbc55x.cpp

@@ -18,6 +18,13 @@ ToDo:
 
 #include "emu.h"
 #include "includes/mbc55x.h"
+#include "bus/isa/isa.h"
+#include "bus/isa/isa_cards.h"
+//#include "bus/pc_joy/pc_joy.h"
+#include "bus/rs232/rs232.h"
+#include "cpu/mcs48/mcs48.h"
+#include "machine/clock.h"
+#include "machine/input_merger.h"
 #include "screen.h"
 #include "softlist.h"
 #include "speaker.h"
@@ -61,16 +68,20 @@ void mbc55x_state::mbc55x_mem(address_map &map)
 
 void mbc55x_state::mbc55x_io(address_map &map)
 {
-	map.global_mask(0xff);
+	map(0x0000, 0x0000).select(0x003e).rw(FUNC(mbc55x_state::iodecode_r), FUNC(mbc55x_state::iodecode_w));
-	map(0x0000, 0x0003).rw(FUNC(mbc55x_state::mbcpic8259_r), FUNC(mbc55x_state::mbcpic8259_w));
+}
-	map(0x0008, 0x000F).rw(FUNC(mbc55x_state::mbc55x_disk_r), FUNC(mbc55x_state::mbc55x_disk_w));
+
-	map(0x0010, 0x0010).rw(FUNC(mbc55x_state::vram_page_r), FUNC(mbc55x_state::vram_page_w));
+void mbc55x_state::mbc55x_iodecode(address_map &map)
-	map(0x0018, 0x001F).rw(FUNC(mbc55x_state::ppi8255_r), FUNC(mbc55x_state::ppi8255_w));
+{
-	map(0x0020, 0x0027).rw(FUNC(mbc55x_state::mbcpit8253_r), FUNC(mbc55x_state::mbcpit8253_w));
+	map(0x00, 0x01).mirror(0x02).rw(m_pic, FUNC(pic8259_device::read), FUNC(pic8259_device::write));
-	map(0x0028, 0x002B).rw(FUNC(mbc55x_state::mbc55x_usart_r), FUNC(mbc55x_state::mbc55x_usart_w));
+	map(0x04, 0x07).rw(m_fdc, FUNC(fd1793_device::read), FUNC(fd1793_device::write));
-	map(0x0030, 0x0031).rw(m_crtc, FUNC(mc6845_device::status_r), FUNC(mc6845_device::address_w));
+	map(0x08, 0x08).mirror(0x03).rw(FUNC(mbc55x_state::vram_page_r), FUNC(mbc55x_state::vram_page_w));
-	map(0x0032, 0x0033).rw(m_crtc, FUNC(mc6845_device::register_r), FUNC(mc6845_device::register_w));
+	map(0x0c, 0x0f).rw(m_ppi, FUNC(i8255_device::read), FUNC(i8255_device::write));
-	map(0x0038, 0x003B).rw(FUNC(mbc55x_state::mbc55x_kb_usart_r), FUNC(mbc55x_state::mbc55x_kb_usart_w));
+	map(0x10, 0x13).rw(m_pit, FUNC(pit8253_device::read), FUNC(pit8253_device::write));
+	map(0x14, 0x15).mirror(0x02).rw("sio", FUNC(i8251_device::read), FUNC(i8251_device::write));
+	map(0x18, 0x18).mirror(0x02).rw(m_crtc, FUNC(mc6845_device::status_r), FUNC(mc6845_device::address_w));
+	map(0x19, 0x19).mirror(0x02).rw(m_crtc, FUNC(mc6845_device::register_r), FUNC(mc6845_device::register_w));
+	map(0x1c, 0x1d).mirror(0x02).r(FUNC(mbc55x_state::mbc55x_kb_usart_r)).w(m_kb_uart, FUNC(i8251_device::write));
 }
 
 static INPUT_PORTS_START( mbc55x )
@@ -138,7 +149,7 @@ static INPUT_PORTS_START( mbc55x )
 
 	PORT_START("KEY6") /* Key row 6 scancodes 30..37 */
 	PORT_BIT(0x01, IP_ACTIVE_LOW, IPT_KEYBOARD) PORT_NAME("SPACE")  PORT_CODE(KEYCODE_SPACE)        PORT_CHAR(' ')
-	PORT_BIT(0x02, IP_ACTIVE_LOW, IPT_UNUSED)
+	PORT_BIT(0x02, IP_ACTIVE_LOW, IPT_KEYBOARD)                     PORT_CODE(KEYCODE_BACKSPACE) PORT_CHAR(0x08)
 	PORT_BIT(0x04, IP_ACTIVE_LOW, IPT_UNUSED)
 	PORT_BIT(0x08, IP_ACTIVE_LOW, IPT_UNUSED)
 	PORT_BIT(0x10, IP_ACTIVE_LOW, IPT_UNUSED)
@@ -243,21 +254,26 @@ static void mbc55x_floppies(device_slot_interface &device)
 
 MACHINE_CONFIG_START(mbc55x_state::mbc55x)
 	/* basic machine hardware */
-	I8088(config, m_maincpu, 3600000);
+	I8088(config, m_maincpu, 14.318181_MHz_XTAL / 4);
 	m_maincpu->set_addrmap(AS_PROGRAM, &mbc55x_state::mbc55x_mem);
 	m_maincpu->set_addrmap(AS_IO, &mbc55x_state::mbc55x_io);
 	m_maincpu->set_irq_acknowledge_callback(PIC8259_TAG, FUNC(pic8259_device::inta_cb));
 
+	ADDRESS_MAP_BANK(config, m_iodecode);
+	m_iodecode->endianness(ENDIANNESS_LITTLE);
+	m_iodecode->data_width(8);
+	m_iodecode->addr_width(5);
+	m_iodecode->set_addrmap(0, &mbc55x_state::mbc55x_iodecode);
+
+	I8049(config, "kbdc", 6_MHz_XTAL).set_disable();
+
 	/* video hardware */
-	MCFG_SCREEN_ADD(SCREEN_TAG, RASTER)
+	screen_device &screen(SCREEN(config, SCREEN_TAG, SCREEN_TYPE_RASTER));
-	MCFG_SCREEN_RAW_PARAMS(14.318181_MHz_XTAL, 896, 0, 300, 262, 0, 200)
+	screen.set_raw(14.318181_MHz_XTAL, 896, 0, 640, 262, 0, 200);
-	MCFG_SCREEN_UPDATE_DEVICE(VID_MC6845_NAME, mc6845_device, screen_update)
+	screen.set_screen_update(VID_MC6845_NAME, FUNC(mc6845_device::screen_update));
-	MCFG_SCREEN_VBLANK_CALLBACK(WRITELINE(*this, mbc55x_state, screen_vblank_mbc55x))
 
 	MCFG_PALETTE_ADD("palette", SCREEN_NO_COLOURS * 3)
 	MCFG_PALETTE_INIT_OWNER(mbc55x_state, mbc55x)
-//  MCFG_SCREEN_SIZE(650, 260)
-//  MCFG_SCREEN_VISIBLE_AREA(0, 639, 0, 249)
 
 	RAM(config, RAM_TAG).set_default_size("128K").set_extra_options("128K,192K,256K,320K,384K,448K,512K,576K,640K");
 
@@ -266,29 +282,36 @@ MACHINE_CONFIG_START(mbc55x_state::mbc55x)
 	SPEAKER_SOUND(config, "speaker").add_route(ALL_OUTPUTS, MONO_TAG, 0.75);
 
 	/* Devices */
-	I8251(config, m_kb_uart, 0);
+	I8251(config, m_kb_uart, 14.318181_MHz_XTAL / 8);
+	m_kb_uart->txd_handler().set("speaker", FUNC(speaker_sound_device::level_w)).invert();
+	m_kb_uart->rts_handler().set(m_printer, FUNC(centronics_device::write_init)).invert();
 	m_kb_uart->rxrdy_handler().set(m_pic, FUNC(pic8259_device::ir3_w));
 
 	PIT8253(config, m_pit, 0);
-	m_pit->set_clk<0>(PIT_C0_CLOCK);
 	m_pit->out_handler<0>().set(m_pic, FUNC(pic8259_device::ir0_w));
-	m_pit->set_clk<1>(PIT_C1_CLOCK);
+	m_pit->out_handler<0>().append(m_pit, FUNC(pit8253_device::write_clk1));
 	m_pit->out_handler<1>().set(m_pic, FUNC(pic8259_device::ir1_w));
-	m_pit->set_clk<2>(PIT_C2_CLOCK);
+	m_pit->set_clk<2>(14.318181_MHz_XTAL / 8);
-	m_pit->out_handler<2>().set(FUNC(mbc55x_state::pit8253_t2));
+	m_pit->out_handler<2>().set("sio", FUNC(i8251_device::write_txc));
+	m_pit->out_handler<2>().append("sio", FUNC(i8251_device::write_rxc));
+	m_pit->out_handler<2>().append("line", FUNC(rs232_port_device::write_etc));
+
+	clock_device &clk_78_6khz(CLOCK(config, "clk_78.6khz", 14.318181_MHz_XTAL / 14 / 13));
+	clk_78_6khz.signal_handler().set(m_pit, FUNC(pit8253_device::write_clk0));
+	clk_78_6khz.signal_handler().append(m_kb_uart, FUNC(i8251_device::write_txc));
+	clk_78_6khz.signal_handler().append(m_kb_uart, FUNC(i8251_device::write_rxc));
 
 	PIC8259(config, m_pic, 0);
 	m_pic->out_int_callback().set_inputline(m_maincpu, INPUT_LINE_IRQ0);
 
 	I8255(config, m_ppi);
-	m_ppi->in_pa_callback().set(FUNC(mbc55x_state::mbc55x_ppi_porta_r));
+	m_ppi->in_pa_callback().set(FUNC(mbc55x_state::game_io_r));
-	m_ppi->out_pa_callback().set(FUNC(mbc55x_state::mbc55x_ppi_porta_w));
+	m_ppi->out_pa_callback().set(FUNC(mbc55x_state::game_io_w));
-	m_ppi->in_pb_callback().set(FUNC(mbc55x_state::mbc55x_ppi_portb_r));
+	m_ppi->out_pb_callback().set(FUNC(mbc55x_state::printer_data_w));
-	m_ppi->out_pb_callback().set(FUNC(mbc55x_state::mbc55x_ppi_portb_w));
+	m_ppi->in_pc_callback().set(FUNC(mbc55x_state::printer_status_r));
-	m_ppi->in_pc_callback().set(FUNC(mbc55x_state::mbc55x_ppi_portc_r));
+	m_ppi->out_pc_callback().set(FUNC(mbc55x_state::disk_select_w));
-	m_ppi->out_pc_callback().set(FUNC(mbc55x_state::mbc55x_ppi_portc_w));
 
-	MCFG_MC6845_ADD(VID_MC6845_NAME, MC6845, SCREEN_TAG, 14.318181_MHz_XTAL / 8)
+	MCFG_MC6845_ADD(VID_MC6845_NAME, HD6845, SCREEN_TAG, 14.318181_MHz_XTAL / 8) // HD46505SP-1
 	MCFG_MC6845_SHOW_BORDER_AREA(false)
 	MCFG_MC6845_CHAR_WIDTH(8)
 	MCFG_MC6845_UPDATE_ROW_CB(mbc55x_state, crtc_update_row)
@@ -296,25 +319,56 @@ MACHINE_CONFIG_START(mbc55x_state::mbc55x)
 	MCFG_MC6845_OUT_HSYNC_CB(WRITELINE(*this, mbc55x_state, vid_vsync_changed))
 
 	/* Backing storage */
-	FD1793(config, m_fdc, 1_MHz_XTAL);
+	FD1793(config, m_fdc, 14.318181_MHz_XTAL / 14); // M5W1793-02P (clock is nominally 1 MHz)
+	m_fdc->intrq_wr_callback().set(m_pic, FUNC(pic8259_device::ir5_w));
 
-	MCFG_FLOPPY_DRIVE_ADD(FDC_TAG ":0", mbc55x_floppies, "qd", mbc55x_state::floppy_formats)
+	MCFG_FLOPPY_DRIVE_ADD(m_floppy[0], mbc55x_floppies, "qd", mbc55x_state::floppy_formats)
-	MCFG_FLOPPY_DRIVE_ADD(FDC_TAG ":1", mbc55x_floppies, "qd", mbc55x_state::floppy_formats)
+	MCFG_FLOPPY_DRIVE_ADD(m_floppy[1], mbc55x_floppies, "qd", mbc55x_state::floppy_formats)
-	MCFG_FLOPPY_DRIVE_ADD(FDC_TAG ":2", mbc55x_floppies, "", mbc55x_state::floppy_formats)
+	MCFG_FLOPPY_DRIVE_ADD(m_floppy[2], mbc55x_floppies, "", mbc55x_state::floppy_formats)
-	MCFG_FLOPPY_DRIVE_ADD(FDC_TAG ":3", mbc55x_floppies, "", mbc55x_state::floppy_formats)
+	MCFG_FLOPPY_DRIVE_ADD(m_floppy[3], mbc55x_floppies, "", mbc55x_state::floppy_formats)
 
 	/* Software list */
 	MCFG_SOFTWARE_LIST_ADD("disk_list","mbc55x")
+
+	MCFG_DEVICE_ADD("isa", ISA8, 0)
+	MCFG_ISA8_CPU(m_maincpu)
+	MCFG_ISA_OUT_IRQ7_CB(WRITELINE(m_pic, pic8259_device, ir7_w)) // all other IRQ and DRQ lines are NC
+	//MCFG_ISA_BUS_IOCHCK(INPUTLINE(m_maincpu, INPUT_LINE_NMI))
+
+	ISA8_SLOT(config, "external", 0, "isa", pc_isa8_cards, nullptr, false);
+
+	i8251_device &sio(I8251(config, "sio", 14.318181_MHz_XTAL / 8)); // on separate board, through 20-pin header
+	sio.dtr_handler().set("line", FUNC(rs232_port_device::write_dtr));
+	sio.txd_handler().set("line", FUNC(rs232_port_device::write_txd));
+	sio.rts_handler().set("line", FUNC(rs232_port_device::write_rts));
+	sio.rxrdy_handler().set("sioint", FUNC(input_merger_device::in_w<0>));
+	sio.txrdy_handler().set("sioint", FUNC(input_merger_device::in_w<1>));
+
+	rs232_port_device &serial(RS232_PORT(config, "line", default_rs232_devices, nullptr));
+	serial.rxd_handler().set("sio", FUNC(i8251_device::write_rxd));
+	serial.dsr_handler().set("sio", FUNC(i8251_device::write_dsr));
+	serial.cts_handler().set("sio", FUNC(i8251_device::write_cts));
+
+	INPUT_MERGER_ANY_HIGH(config, "sioint").output_handler().set(m_pic, FUNC(pic8259_device::ir2_w));
+
+	CENTRONICS(config, m_printer, centronics_devices, nullptr);
+	m_printer->busy_handler().set(FUNC(mbc55x_state::printer_busy_w)).invert(); // LS14 Schmitt trigger
+	m_printer->busy_handler().append(m_pic, FUNC(pic8259_device::ir4_w)).invert();
+	m_printer->perror_handler().set(FUNC(mbc55x_state::printer_paper_end_w));
+	m_printer->select_handler().set(FUNC(mbc55x_state::printer_select_w));
 MACHINE_CONFIG_END
 
 
 ROM_START( mbc55x )
-	ROM_REGION( 0x4000, MAINCPU_TAG, 0 )
+	ROM_REGION(0x4000, MAINCPU_TAG, 0)
 
 	ROM_SYSTEM_BIOS(0, "v120", "mbc55x BIOS v1.20 (1983)")
-	ROMX_LOAD("mbc55x-v120.rom", 0x0000, 0x2000, CRC(b439b4b8) SHA1(6e8df0f3868e3fd0229a5c2720d6c01e46815cab), ROM_BIOS(0)  )
+	ROMX_LOAD("mbc55x-v120.rom", 0x0000, 0x2000, CRC(b439b4b8) SHA1(6e8df0f3868e3fd0229a5c2720d6c01e46815cab), ROM_BIOS(0))
+
+	ROM_REGION(0x0800, "kbdc", 0)
+	ROM_LOAD("d8049hc.m1", 0x0000, 0x0800, NO_DUMP)
 ROM_END
 
 
 //    YEAR  NAME    PARENT  COMPAT  MACHINE  INPUT   CLASS         INIT        COMPANY  FULLNAME   FLAGS
-COMP( 1983, mbc55x, 0,      0,      mbc55x,  mbc55x, mbc55x_state, empty_init, "Sanyo", "MBC-55x", 0 /*MACHINE_NO_SOUND*/)
+COMP( 1983, mbc55x, 0,      0,      mbc55x,  mbc55x, mbc55x_state, empty_init, "Sanyo", "MBC-55x", 0 )

src/mame/includes/mbc55x.h

@@ -15,6 +15,7 @@
 #include "bus/centronics/ctronics.h"
 #include "cpu/i86/i86.h"
 #include "imagedev/flopdrv.h"
+#include "machine/bankdev.h"
 #include "machine/i8251.h"
 #include "machine/i8255.h"
 #include "machine/pic8259.h"
@@ -72,12 +73,7 @@
 
 #define PPI8255_TAG     "ppi8255"
 #define PIC8259_TAG     "pic8259"
-
-// From tech manual clock c1 is fed from c0, but it approx 100Hz
 #define PIT8253_TAG     "pit8253"
-#define PIT_C0_CLOCK    78600
-#define PIT_C1_CLOCK    100
-#define PIT_C2_CLOCK    1789770
 
 #define MONO_TAG                "mono"
 #define I8251A_KB_TAG           "i8251a_kb"
@@ -99,16 +95,15 @@ public:
 	mbc55x_state(const machine_config &mconfig, device_type type, const char *tag)
 		: driver_device(mconfig, type, tag),
 		m_maincpu(*this, MAINCPU_TAG),
+		m_iodecode(*this, "iodecode"),
 		m_crtc(*this, VID_MC6845_NAME),
 		m_kb_uart(*this, I8251A_KB_TAG),
 		m_pit(*this, PIT8253_TAG),
 		m_ppi(*this, PPI8255_TAG),
 		m_pic(*this, PIC8259_TAG),
 		m_fdc(*this, FDC_TAG),
-		m_floppy0(*this, FDC_TAG ":0"),
+		m_floppy(*this, FDC_TAG ":%u", 0U),
-		m_floppy1(*this, FDC_TAG ":1"),
+		m_printer(*this, "printer"),
-		m_floppy2(*this, FDC_TAG ":2"),
-		m_floppy3(*this, FDC_TAG ":3"),
 		m_speaker(*this, "speaker"),
 		m_ram(*this, RAM_TAG),
 		m_palette(*this, "palette")
@@ -120,51 +115,37 @@ public:
 	void init_mbc55x();
 
 	required_device<cpu_device> m_maincpu;
+	required_device<address_map_bank_device> m_iodecode;
 	uint32_t      m_debug_machine;
 
 private:
 	DECLARE_FLOPPY_FORMATS(floppy_formats);
 
-	//DECLARE_READ8_MEMBER(pic8259_r);
+	DECLARE_READ8_MEMBER(iodecode_r);
-	//DECLARE_WRITE8_MEMBER(pic8259_w);
+	DECLARE_WRITE8_MEMBER(iodecode_w);
-	//DECLARE_READ8_MEMBER(mbc55x_disk_r);
+
-	//DECLARE_WRITE8_MEMBER(mbc55x_disk_w);
+	DECLARE_READ8_MEMBER(mbc55x_kb_usart_r);
-	DECLARE_READ8_MEMBER(mbc55x_usart_r);
-	DECLARE_WRITE8_MEMBER(mbc55x_usart_w);
-	//DECLARE_READ8_MEMBER(mbc55x_kb_usart_r);
-	//DECLARE_WRITE8_MEMBER(mbc55x_kb_usart_w);
 	DECLARE_READ8_MEMBER(vram_page_r);
 	DECLARE_WRITE8_MEMBER(vram_page_w);
-	DECLARE_READ8_MEMBER(ppi8255_r);
+	DECLARE_READ8_MEMBER(game_io_r);
-	DECLARE_WRITE8_MEMBER(ppi8255_w);
+	DECLARE_WRITE8_MEMBER(game_io_w);
-	//DECLARE_READ8_MEMBER(pit8253_r);
+	DECLARE_READ8_MEMBER(printer_status_r);
-	//DECLARE_WRITE8_MEMBER(pit8253_w);
+	DECLARE_WRITE8_MEMBER(printer_data_w);
-	DECLARE_READ8_MEMBER(mbc55x_ppi_porta_r);
+	DECLARE_WRITE8_MEMBER(disk_select_w);
-	DECLARE_READ8_MEMBER(mbc55x_ppi_portb_r);
+	DECLARE_WRITE_LINE_MEMBER(printer_busy_w);
-	DECLARE_READ8_MEMBER(mbc55x_ppi_portc_r);
+	DECLARE_WRITE_LINE_MEMBER(printer_paper_end_w);
-	DECLARE_WRITE8_MEMBER(mbc55x_ppi_porta_w);
+	DECLARE_WRITE_LINE_MEMBER(printer_select_w);
-	DECLARE_WRITE8_MEMBER(mbc55x_ppi_portb_w);
+
-	DECLARE_WRITE8_MEMBER(mbc55x_ppi_portc_w);
 	DECLARE_WRITE_LINE_MEMBER(vid_hsync_changed);
 	DECLARE_WRITE_LINE_MEMBER(vid_vsync_changed);
-	DECLARE_WRITE_LINE_MEMBER(pit8253_t2);
-
-	DECLARE_READ8_MEMBER(mbcpic8259_r);
-	DECLARE_WRITE8_MEMBER(mbcpic8259_w);
-	DECLARE_READ8_MEMBER(mbcpit8253_r);
-	DECLARE_WRITE8_MEMBER(mbcpit8253_w);
-	DECLARE_READ8_MEMBER(mbc55x_disk_r);
-	DECLARE_WRITE8_MEMBER(mbc55x_disk_w);
-	DECLARE_READ8_MEMBER(mbc55x_kb_usart_r);
-	DECLARE_WRITE8_MEMBER(mbc55x_kb_usart_w);
 
 	MC6845_UPDATE_ROW(crtc_update_row);
 	DECLARE_PALETTE_INIT(mbc55x);
-	DECLARE_WRITE_LINE_MEMBER(screen_vblank_mbc55x);
 	TIMER_CALLBACK_MEMBER(keyscan_callback);
 
 	void mbc55x_io(address_map &map);
 	void mbc55x_mem(address_map &map);
+	void mbc55x_iodecode(address_map &map);
 
 	virtual void machine_start() override;
 	virtual void machine_reset() override;
@@ -181,10 +162,8 @@ private:
 	required_device<i8255_device> m_ppi;
 	required_device<pic8259_device> m_pic;
 	required_device<fd1793_device> m_fdc;
-	required_device<floppy_connector> m_floppy0;
+	required_device_array<floppy_connector, 4> m_floppy;
-	required_device<floppy_connector> m_floppy1;
+	required_device<centronics_device> m_printer;
-	required_device<floppy_connector> m_floppy2;
-	required_device<floppy_connector> m_floppy3;
 	required_device<speaker_sound_device> m_speaker;
 	required_device<ram_device> m_ram;
 	required_device<palette_device> m_palette;
@@ -192,6 +171,7 @@ private:
 	uint32_t      m_debug_video;
 	uint8_t       m_video_mem[VIDEO_MEM_SIZE];
 	uint8_t       m_vram_page;
+	uint8_t       m_printer_status;
 
 	keyboard_t  m_keyboard;
 

src/mame/machine/mbc55x.cpp

@@ -38,51 +38,54 @@ static int instruction_hook(device_t &device, offs_t curpc);
 //static void fdc_reset(running_machine &machine);
 //static void set_disk_int(running_machine &machine, int state);
 
+READ8_MEMBER(mbc55x_state::iodecode_r)
+{
+	return m_iodecode->read8(space, offset >> 1);
+}
+
+WRITE8_MEMBER(mbc55x_state::iodecode_w)
+{
+	m_iodecode->write8(space, offset >> 1, data);
+}
+
 /* 8255 Configuration */
 
-READ8_MEMBER( mbc55x_state::ppi8255_r )
+READ8_MEMBER(mbc55x_state::game_io_r)
-{
-	return m_ppi->read(offset>>1);
-}
-
-WRITE8_MEMBER( mbc55x_state::ppi8255_w )
-{
-	m_ppi->write(offset>>1, data);
-}
-
-READ8_MEMBER( mbc55x_state::mbc55x_ppi_porta_r )
 {
 	return 0xff;
 }
 
-READ8_MEMBER( mbc55x_state::mbc55x_ppi_portb_r )
+WRITE8_MEMBER(mbc55x_state::game_io_w)
-{
-	return 0xff;
-}
-
-READ8_MEMBER( mbc55x_state::mbc55x_ppi_portc_r )
-{
-	return 0xff;
-}
-
-WRITE8_MEMBER( mbc55x_state::mbc55x_ppi_porta_w )
 {
 }
 
-WRITE8_MEMBER( mbc55x_state::mbc55x_ppi_portb_w )
+READ8_MEMBER( mbc55x_state::printer_status_r)
 {
+	return m_printer_status;
 }
 
-WRITE8_MEMBER( mbc55x_state::mbc55x_ppi_portc_w )
+WRITE8_MEMBER(mbc55x_state::printer_data_w)
+{
+	m_printer->write_data7(!BIT(data, 7));
+	m_printer->write_data6(!BIT(data, 6));
+	m_printer->write_data5(!BIT(data, 5));
+	m_printer->write_data4(!BIT(data, 4));
+	m_printer->write_data3(!BIT(data, 3));
+	m_printer->write_data2(!BIT(data, 2));
+	m_printer->write_data1(!BIT(data, 1));
+	m_printer->write_data0(!BIT(data, 0));
+}
+
+WRITE8_MEMBER(mbc55x_state::disk_select_w)
 {
 	floppy_image_device *floppy = nullptr;
 
 	switch (data & 0x03)
 	{
-	case 0: floppy = m_floppy0->get_device(); break;
+	case 0: floppy = m_floppy[0]->get_device(); break;
-	case 1: floppy = m_floppy1->get_device(); break;
+	case 1: floppy = m_floppy[1]->get_device(); break;
-	case 2: floppy = m_floppy2->get_device(); break;
+	case 2: floppy = m_floppy[2]->get_device(); break;
-	case 3: floppy = m_floppy3->get_device(); break;
+	case 3: floppy = m_floppy[3]->get_device(); break;
 	}
 
 	m_fdc->set_floppy(floppy);
@@ -92,45 +95,23 @@ WRITE8_MEMBER( mbc55x_state::mbc55x_ppi_portc_w )
 		floppy->mon_w(0);
 		floppy->ss_w(BIT(data, 2));
 	}
+
+	m_printer->write_strobe(!BIT(data, 3));
 }
 
-/* Serial port USART, unimplemented as yet */
+WRITE_LINE_MEMBER(mbc55x_state::printer_busy_w)
-
-READ8_MEMBER( mbc55x_state::mbc55x_usart_r )
 {
-	return 0;
+	m_printer_status = (m_printer_status & 0xef) | (state ? 0x10 : 0x00);
 }
 
-WRITE8_MEMBER( mbc55x_state::mbc55x_usart_w )
+WRITE_LINE_MEMBER(mbc55x_state::printer_paper_end_w)
 {
+	m_printer_status = (m_printer_status & 0xdf) | (state ? 0x20 : 0x00);
 }
 
-/* PIC 8259 Configuration */
+WRITE_LINE_MEMBER(mbc55x_state::printer_select_w)
-
-READ8_MEMBER(mbc55x_state::mbcpic8259_r)
 {
-	return m_pic->read(offset>>1);
+	m_printer_status = (m_printer_status & 0xbf) | (state ? 0x40 : 0x00);
-}
-
-WRITE8_MEMBER(mbc55x_state::mbcpic8259_w)
-{
-	m_pic->write(offset>>1, data);
-}
-
-READ8_MEMBER(mbc55x_state::mbcpit8253_r)
-{
-	return m_pit->read(offset >> 1);
-}
-
-WRITE8_MEMBER(mbc55x_state::mbcpit8253_w)
-{
-	m_pit->write(offset >> 1, data);
-}
-
-WRITE_LINE_MEMBER( mbc55x_state::pit8253_t2 )
-{
-	m_kb_uart->write_txc(state);
-	m_kb_uart->write_rxc(state);
 }
 
 /* Video ram page register */
@@ -147,16 +128,6 @@ WRITE8_MEMBER( mbc55x_state::vram_page_w )
 	m_vram_page=data;
 }
 
-READ8_MEMBER(mbc55x_state::mbc55x_disk_r)
-{
-	return m_fdc->read(offset>>1);
-}
-
-WRITE8_MEMBER(mbc55x_state::mbc55x_disk_w)
-{
-	m_fdc->write(offset>>1, data);
-}
-
 
 /*
     Keyboard emulation
@@ -195,9 +166,9 @@ void mbc55x_state::scan_keyboard()
 		{ '9',  '0', '-', '=',  '\\', 'q',  'w',  'e' },
 		{ 'r',  't', 'y', 'u',  'i',  'o',  'p',  '[' },
 		{ ']',  'a', 's', 'd',  'f',  'g',  'h',  'j' },
-		{ 'k',  'l', ';', '\'', '`',  0x0D,  'z',  'x' },
+		{ 'k',  'l', ';', '\'', '`',  0x0d,  'z',  'x' },
 		{ 'c',  'v', 'b', 'n',  'm',  ',',  '.',  '/', },
-		{ ' ',  ' ', ' ', ' ',  ' ',  ' ',  ' ',  ' ', }
+		{ ' ', 0x08, ' ', ' ',  ' ',  ' ',  ' ',  ' ', }
 
 	};
 
@@ -209,7 +180,7 @@ void mbc55x_state::scan_keyboard()
 		{ '}',  'A', 'S', 'D',  'F',  'G',  'H',  'J' },
 		{ 'K',  'L', ':', '"',  '~',  0x0d, 'Z',  'X' },
 		{ 'C',  'V', 'B', 'N',  'M',  ',',  '?',  '/' },
-		{ ' ',  ' ', ' ', ' ',  ' ',  ' ',  ' ',  ' ' }
+		{ ' ', 0x08, ' ', ' ',  ' ',  ' ',  ' ',  ' ' }
 	};
 
 	// First read shift, control and graph
@@ -246,7 +217,6 @@ TIMER_CALLBACK_MEMBER(mbc55x_state::keyscan_callback)
 READ8_MEMBER(mbc55x_state::mbc55x_kb_usart_r)
 {
 	uint8_t result = 0;
-	offset>>=1;
 
 	switch (offset)
 	{
@@ -264,17 +234,6 @@ READ8_MEMBER(mbc55x_state::mbc55x_kb_usart_r)
 	return result;
 }
 
-WRITE8_MEMBER(mbc55x_state::mbc55x_kb_usart_w)
-{
-	offset>>=1;
-
-	switch (offset)
-	{
-		case 0  : m_kb_uart->data_w(data); break;
-		case 1  : m_kb_uart->control_w(data); break;
-	}
-}
-
 void mbc55x_state::set_ram_size()
 {
 	address_space   &space      = m_maincpu->space( AS_PROGRAM );
@@ -346,8 +305,12 @@ void mbc55x_state::machine_start()
 
 	m_debug_machine=DEBUG_NONE;
 
+	m_printer_status = 0xff;
+
 	// Allocate keyscan timer
 	m_keyboard.keyscan_timer=machine().scheduler().timer_alloc(timer_expired_delegate(FUNC(mbc55x_state::keyscan_callback),this));
+
+	m_kb_uart->write_cts(0);
 }
 
 

src/mame/video/mbc55x.cpp

@@ -183,8 +183,3 @@ void mbc55x_state::video_reset()
 
 	logerror("Video reset\n");
 }
-
-WRITE_LINE_MEMBER(mbc55x_state::screen_vblank_mbc55x)
-{
-//  logerror("screen_vblank_mbc55x\n");
-}