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Diffstat (limited to 'src/mame/ausnz/d6800.cpp')
-rw-r--r-- | src/mame/ausnz/d6800.cpp | 436 |
1 files changed, 436 insertions, 0 deletions
diff --git a/src/mame/ausnz/d6800.cpp b/src/mame/ausnz/d6800.cpp new file mode 100644 index 00000000000..b37905f8d13 --- /dev/null +++ b/src/mame/ausnz/d6800.cpp @@ -0,0 +1,436 @@ +// license:BSD-3-Clause +// copyright-holders:Robbbert +/******************************************************************************** + + The Dream 6800 is a CHIP-8 computer roughly modelled on the Cosmac VIP. + It was described in Electronics Australia magazine in 4 articles starting + in May 1979. It has 1k of ROM and 1k of RAM. The video consists of 64x32 + pixels. The keyboard is a hexcode 4x4 matrix, plus a Function key. + + Designed by Michael Bauer, of the Division of Computing and Mathematics + at Deakin University, Australia. + + NOTE that the display only updates after each 4 digits is entered, and + you can't see what you type as you change bytes. This is by design. + + The cassette has no checksum, header or blocks. It is simply a stream + of pulses. The successful loading of a tape is therefore a matter of luck. + + To modify memory, press RST, then enter the 4-digit address (nothing happens + until the 4th digit is pressed), then press FN, then 0, then the 2 digit data. + It will enter the data (you won't see anything), then the address will increment. + Enter the data for this new address. If you want to skip this address, press FN. + When you're done, press RST. NOTE!!! Do NOT change any of these addresses: + 0000,0001,0006-007F, or the system may crash. It's recommended to start all + your programs at 0200. + + Function keys: + FN 0 - Modify memory - see above paragraph. + + FN 1 - Tape load. You must have entered the start address at 0002, and + the end address+1 at 0004 (big-endian). + + FN 2 - Tape save. You must have entered the start address at 0002, and + the end address+1 at 0004 (big-endian). + + FN 3 - Run. To use, press RST, then enter the 4-digit start address + (nothing happens until the 4th digit is pressed), then FN, then 3. + + All CHIP-8 programs load at 0200 (max size 4k), and exec address + is C000. + + Information and programs can be found at http://chip8.com/?page=78 + + Due to the way the keyboard is scanned, Natural Keyboard/Paste is not possible. + +**********************************************************************************/ + + +#include "emu.h" +#include "cpu/m6800/m6800.h" +#include "imagedev/cassette.h" +#include "imagedev/snapquik.h" +#include "machine/6821pia.h" +#include "machine/timer.h" +#include "sound/beep.h" +#include "emupal.h" +#include "screen.h" +#include "softlist_dev.h" +#include "speaker.h" + + +namespace { + +class d6800_state : public driver_device +{ +public: + d6800_state(const machine_config &mconfig, device_type type, const char *tag) + : driver_device(mconfig, type, tag) + , m_maincpu(*this, "maincpu") + , m_cass(*this, "cassette") + , m_pia(*this, "pia") + , m_beeper(*this, "beeper") + , m_videoram(*this, "videoram") + , m_io_keyboard(*this, "X%u", 0U) + , m_io_shift(*this, "SHIFT") + { } + + + void d6800(machine_config &config); + + DECLARE_INPUT_CHANGED_MEMBER(reset_button); + +private: + uint8_t d6800_cassette_r(); + void d6800_cassette_w(uint8_t data); + uint8_t d6800_keyboard_r(); + void d6800_keyboard_w(uint8_t data); + void d6800_screen_w(int state); + uint32_t screen_update_d6800(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect); + INTERRUPT_GEN_MEMBER(rtc_interrupt); + TIMER_DEVICE_CALLBACK_MEMBER(kansas_w); + TIMER_DEVICE_CALLBACK_MEMBER(kansas_r); + DECLARE_QUICKLOAD_LOAD_MEMBER(quickload_cb); + + void d6800_map(address_map &map) ATTR_COLD; + + bool m_cb2 = 0; + bool m_cassold = 0; + uint8_t m_cass_data[4]{}; + uint8_t m_portb = 0U; + virtual void machine_start() override ATTR_COLD; + virtual void machine_reset() override ATTR_COLD; + required_device<cpu_device> m_maincpu; + required_device<cassette_image_device> m_cass; + required_device<pia6821_device> m_pia; + required_device<beep_device> m_beeper; + required_shared_ptr<uint8_t> m_videoram; + required_ioport_array<4> m_io_keyboard; + required_ioport m_io_shift; +}; + + +/* Memory Maps */ + +void d6800_state::d6800_map(address_map &map) +{ + map(0x0000, 0x00ff).ram(); + map(0x0100, 0x01ff).ram().share("videoram"); + map(0x0200, 0x17ff).ram(); + //map(0x1800, 0x1fff).rom().region("maincpu",0x800); // for dreamsoft_1, if we can find a good copy + map(0x8010, 0x8013).rw(m_pia, FUNC(pia6821_device::read), FUNC(pia6821_device::write)); + map(0xc000, 0xc7ff).mirror(0x3800).rom().region("maincpu",0); +} + +/* Input Ports */ + +static INPUT_PORTS_START( d6800 ) + PORT_START("X0") + PORT_BIT( 0x01, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_0) PORT_NAME("0") // ee + PORT_BIT( 0x02, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_1) PORT_NAME("1") // ed + PORT_BIT( 0x04, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_2) PORT_CODE(KEYCODE_UP) PORT_NAME("2") // eb + PORT_BIT( 0x08, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_3) PORT_NAME("3") // e7 + PORT_BIT( 0xf0, IP_ACTIVE_LOW, IPT_UNUSED ) + + PORT_START("X1") + PORT_BIT( 0x01, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_4) PORT_CODE(KEYCODE_LEFT) PORT_NAME("4") // de + PORT_BIT( 0x02, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_5) PORT_NAME("5") // dd + PORT_BIT( 0x04, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_6) PORT_CODE(KEYCODE_RIGHT) PORT_NAME("6") // db + PORT_BIT( 0x08, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_7) PORT_NAME("7") // d7 + PORT_BIT( 0xf0, IP_ACTIVE_LOW, IPT_UNUSED ) + + PORT_START("X2") + PORT_BIT( 0x01, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_8) PORT_CODE(KEYCODE_DOWN) PORT_NAME("8") // be + PORT_BIT( 0x02, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_9) PORT_NAME("9") // bd + PORT_BIT( 0x04, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_A) PORT_NAME("A") // bb + PORT_BIT( 0x08, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_B) PORT_NAME("B") // b7 + PORT_BIT( 0xf0, IP_ACTIVE_LOW, IPT_UNUSED ) + + PORT_START("X3") + PORT_BIT( 0x01, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_C) PORT_NAME("C") // 7e + PORT_BIT( 0x02, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_D) PORT_NAME("D") // 7d + PORT_BIT( 0x04, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_E) PORT_NAME("E") // 7b + PORT_BIT( 0x08, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_F) PORT_NAME("F") // 77 + PORT_BIT( 0xf0, IP_ACTIVE_LOW, IPT_UNUSED ) + + PORT_START("SHIFT") + PORT_BIT( 0x01, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_NAME("FN") PORT_CODE(KEYCODE_LSHIFT) + + PORT_START("RESET") + PORT_BIT( 0x01, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_NAME("RST") PORT_CODE(KEYCODE_LALT) PORT_CHANGED_MEMBER(DEVICE_SELF, FUNC(d6800_state::reset_button), 0) + + PORT_START("VS") + PORT_BIT( 0x01, IP_ACTIVE_HIGH, IPT_CUSTOM) PORT_READ_LINE_DEVICE_MEMBER("screen", FUNC(screen_device::vblank)) +INPUT_PORTS_END + +INPUT_CHANGED_MEMBER(d6800_state::reset_button) +{ + // RESET button wired to POR on the mc6875, which activates the Reset output pin which in turn connects to the CPU's Reset pin. + if (newval) + m_pia->reset(); + m_maincpu->set_input_line(INPUT_LINE_RESET, newval ? ASSERT_LINE : CLEAR_LINE); +} + +/* Video */ +uint32_t d6800_state::screen_update_d6800(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect) +{ + uint8_t gfx=0; + + for (uint8_t y = 0; y < 32; y++) + { + uint16_t *p = &bitmap.pix(y); + + for (uint8_t x = 0; x < 8; x++) + { + if (m_cb2) + gfx = m_videoram[x | (y<<3)]; + + *p++ = BIT(gfx, 7); + *p++ = BIT(gfx, 6); + *p++ = BIT(gfx, 5); + *p++ = BIT(gfx, 4); + *p++ = BIT(gfx, 3); + *p++ = BIT(gfx, 2); + *p++ = BIT(gfx, 1); + *p++ = BIT(gfx, 0); + } + } + return 0; +} + +/* NE556 */ + +TIMER_DEVICE_CALLBACK_MEMBER(d6800_state::kansas_w) +{ + m_cass_data[3]++; + + if (BIT(m_portb, 0) != m_cassold) + { + m_cass_data[3] = 0; + m_cassold = BIT(m_portb, 0); + } + + if (BIT(m_portb, 0)) + m_cass->output(BIT(m_cass_data[3], 0) ? -1.0 : +1.0); // 2400Hz + else + m_cass->output(BIT(m_cass_data[3], 1) ? -1.0 : +1.0); // 1200Hz +} + +/* PIA6821 Interface */ + +TIMER_DEVICE_CALLBACK_MEMBER(d6800_state::kansas_r) +{ + uint8_t data = m_io_keyboard[0]->read() & m_io_keyboard[1]->read() & m_io_keyboard[2]->read() & m_io_keyboard[3]->read(); + int ca1 = (data == 255) ? 0 : 1; + int ca2 = m_io_shift->read(); + + m_pia->ca1_w(ca1); + m_pia->ca2_w(ca2); + + /* cassette - turn 1200/2400Hz to a bit */ + m_cass_data[1]++; + uint8_t cass_ws = (m_cass->input() > +0.03) ? 1 : 0; + + if (cass_ws != m_cass_data[0]) + { + m_cass_data[0] = cass_ws; + m_cass_data[2] = ((m_cass_data[1] < 12) ? 128 : 0); + m_cass_data[1] = 0; + } +} + + +void d6800_state::d6800_screen_w(int state) +{ + m_cb2 = state; + m_maincpu->set_unscaled_clock(state ? 589744 : 1e6); // effective clock is ~590kHz while screen is on +} + +uint8_t d6800_state::d6800_cassette_r() +{ + /* + Cassette circuit consists of a 741 op-amp, a 74121 oneshot, and a 74LS74. + When a pulse arrives, the oneshot is set. After a preset time, it triggers + and the 74LS74 compares this pulse to the output of the 741. Therefore it + knows if the tone is 1200 or 2400 Hz. Input to PIA is bit 7. + */ + + return m_cass_data[2] | m_portb; +} + +void d6800_state::d6800_cassette_w(uint8_t data) +{ + /* + A NE556 runs at either 1200 or 2400 Hz, depending on the state of bit 0. + This output drives the speaker and the output signal to the cassette player. + Bit 6 enables the speaker. Also the speaker is silenced when cassette operations + are in progress (DMA/CB2 line low). + */ + + m_beeper->set_clock(BIT(data, 0) ? 2400 : 1200); + m_beeper->set_state(BIT(data, 6) & (m_cb2 ? 1 : 0)); + + m_portb = data & 0x7f; +} + +uint8_t d6800_state::d6800_keyboard_r() +{ + /* + This system reads the key matrix one way, then swaps the input and output + lines around and reads it another way. This isolates the key that was pressed. + */ + + u8 y = 8; + for (u8 i = 0; i < 4; i++) + { + u8 data = m_io_keyboard[i]->read() & 15; + y <<= 1; + if (data < 15) + for (u8 j = 0; j < 4; j++) + if (!BIT(data, j)) + return data | (0xf0 - y); + } + + return 0xff; +} + +void d6800_state::d6800_keyboard_w(uint8_t data) +{ + /* + + bit description + + PA0 keyboard column 0 + PA1 keyboard column 1 + PA2 keyboard column 2 + PA3 keyboard column 3 + PA4 keyboard row 0 + PA5 keyboard row 1 + PA6 keyboard row 2 + PA7 keyboard row 3 + + */ + +} + +INTERRUPT_GEN_MEMBER(d6800_state::rtc_interrupt) +{ + m_pia->cb1_w(1); + m_pia->cb1_w(0); +} + +/* Machine Initialization */ + +void d6800_state::machine_start() +{ + save_item(NAME(m_cb2)); + save_item(NAME(m_cassold)); + save_item(NAME(m_cass_data)); + save_item(NAME(m_portb)); +} + +void d6800_state::machine_reset() +{ + m_beeper->set_state(0); + m_cass_data[0] = 0; + m_cass_data[1] = 0; + m_cass_data[2] = 128; + m_cass_data[3] = 0; +} + +/* Machine Drivers */ + +QUICKLOAD_LOAD_MEMBER(d6800_state::quickload_cb) +{ + constexpr u16 QUICK_ADDR = 0x200; + + u32 const quick_length = image.length(); + if (quick_length > 0xe00) + return std::make_pair(image_error::INVALIDIMAGE, "File exceeds 3584 bytes"); + + address_space &space = m_maincpu->space(AS_PROGRAM); + for (u32 i = 0; i < quick_length; i++) + { + u8 ch; + image.fread(&ch, 1); + space.write_byte(i + QUICK_ADDR, ch); + } + + u16 exec_addr = 0xc000; + if (image.is_filetype("bin")) + exec_addr = QUICK_ADDR; + + // display a message about the loaded quickload + image.message(" Quickload: size=%04X : start=%04X : end=%04X : exec=%04X", quick_length, QUICK_ADDR, QUICK_ADDR+quick_length, exec_addr); + + // Start the quickload + m_maincpu->set_pc(exec_addr); + + return std::make_pair(std::error_condition(), std::string()); +} + +void d6800_state::d6800(machine_config &config) +{ + /* basic machine hardware */ + M6800(config, m_maincpu, XTAL(4'000'000)/4); + m_maincpu->set_addrmap(AS_PROGRAM, &d6800_state::d6800_map); + m_maincpu->set_vblank_int("screen", FUNC(d6800_state::rtc_interrupt)); + + /* video hardware */ + screen_device &screen(SCREEN(config, "screen", SCREEN_TYPE_RASTER)); + screen.set_refresh_hz(50); + screen.set_size(64, 32); + screen.set_visarea_full(); + screen.set_screen_update(FUNC(d6800_state::screen_update_d6800)); + screen.set_vblank_time(ATTOSECONDS_IN_USEC(300)); // verified + screen.set_palette("palette"); + + PALETTE(config, "palette", palette_device::MONOCHROME); + + /* sound hardware */ + SPEAKER(config, "mono").front_center(); + BEEP(config, "beeper", 1200).add_route(ALL_OUTPUTS, "mono", 0.50); + + /* devices */ + PIA6821(config, m_pia); + m_pia->readpa_handler().set(FUNC(d6800_state::d6800_keyboard_r)); + m_pia->readpb_handler().set(FUNC(d6800_state::d6800_cassette_r)); + m_pia->writepa_handler().set(FUNC(d6800_state::d6800_keyboard_w)); + m_pia->writepb_handler().set(FUNC(d6800_state::d6800_cassette_w)); + m_pia->cb2_handler().set(FUNC(d6800_state::d6800_screen_w)); + m_pia->irqa_handler().set_inputline("maincpu", M6800_IRQ_LINE); + m_pia->irqb_handler().set_inputline("maincpu", M6800_IRQ_LINE); + + CASSETTE(config, m_cass); + m_cass->set_default_state(CASSETTE_STOPPED | CASSETTE_MOTOR_ENABLED | CASSETTE_SPEAKER_ENABLED); + m_cass->add_route(ALL_OUTPUTS, "mono", 0.05); + + TIMER(config, "kansas_w").configure_periodic(FUNC(d6800_state::kansas_w), attotime::from_hz(4800)); + TIMER(config, "kansas_r").configure_periodic(FUNC(d6800_state::kansas_r), attotime::from_hz(40000)); + + /* quickload */ + quickload_image_device &quickload(QUICKLOAD(config, "quickload", "bin,c8", attotime::from_seconds(2))); + quickload.set_load_callback(FUNC(d6800_state::quickload_cb)); + quickload.set_interface("chip8quik"); + SOFTWARE_LIST(config, "quik_list").set_original("chip8_quik").set_filter("D"); +} + +/* ROMs */ + +ROM_START( d6800 ) + ROM_REGION( 0x1000, "maincpu", ROMREGION_ERASEFF ) + ROM_SYSTEM_BIOS(0, "0", "Original") // "chipos" + ROMX_LOAD( "d6800.bin", 0x0000, 0x0400, CRC(3f97ca2e) SHA1(60f26e57a058262b30befceceab4363a5d65d877), ROM_BIOS(0) ) + ROM_RELOAD( 0x0400, 0x0400 ) + //ROMX_LOAD( "d6800d1.bin", 0x0800, 0x0800, BAD_DUMP CRC(e552cae3) SHA1(0b90504922d46b9c46278924768c45b1b276709f), ROM_BIOS(0) ) // need a good dump, this one is broken + ROM_SYSTEM_BIOS(1, "d2", "Dreamsoft2") + ROMX_LOAD( "d6800d2.bin", 0x0000, 0x0800, CRC(ded5712f) SHA1(f594f313a74d7135c9fdd0bcb0093fc5771a9b7d), ROM_BIOS(1) ) + ROM_SYSTEM_BIOS(2, "d2m", "Dreamsoft2m") + ROMX_LOAD( "d6800d2m.bin", 0x0000, 0x0800, CRC(eec8e56f) SHA1(f587ccbc0872f2982d61120d033f481a862b902b), ROM_BIOS(2) ) +ROM_END + +} // anonymous namespace + + +// YEAR NAME PARENT COMPAT MACHINE INPUT CLASS INIT COMPANY FULLNAME FLAGS +COMP( 1979, d6800, 0, 0, d6800, d6800, d6800_state, empty_init, "Michael Bauer", "Dream 6800", MACHINE_SUPPORTS_SAVE ) |