// license:BSD-3-Clause // copyright-holders:Wilbert Pol /****************************************************************************** Acorn Electron driver By Wilbert Pol Hardware Overview ----------------- The Acorn Electron is a budget version of the BBC Micro home computer Basic specs are: 6502 CPU @ 2MHz or 1MHz 32k RAM and 32k ROM Text modes: 20x32, 40x25, 40x32, 80x25, 80x32 Graphics modes: 160x256 (4 or 16 colors), 320x256 (2 or 4 colors), 640x256 (2 colors), 320x200 (2 colors), 640x200 (2 colors) Colors: 8 colors (either solid or flashing) Sound: 1 channel, 7 octaves; built-in speaker Internal ports for cassette storage, RGB/CVBS monitors and TV output Various expansions can be added via the rear expansion port PCB Layout ---------- |-------------------| |--------| EXPANSION PORT | |-----|---------------------| |---||---------| |MOD | SPKR 16MHz LS169 18VAC|| []18VAC INPUT | |17.7345MHz ROM 18VAC|| POWER | |-----| 74S04 |----| || SUPPLY | | KBD_CONN 6502 |ULA | || | |CVBS |----| || +5VDC | |RGB LS00 LS86 || -5VDC | | PWR|| | |CASS LM324 LS00 LS86 S74 LS74 4164 4164 4164 4164 || | |------------------------------------------------------------||---------| Notes: (all IC's shown. Only 16 ICs are used) 6502 - 6502 CPU, clock input 2.000MHz [16/8] ULA - Custom logic chip 12CO21, also containing most of the BBC Micro circuitry Early PCB revisions used a PLCC68 chip in a socket. Later revisions used a PGA68 chip soldered directly into the motherboard 4164 - 4164 64k x4-bit DRAM (4 chips for 32kbytes total) ROM - Hitachi HN613256 32k x8-bit mask ROM containing OS & BASIC LM324 - Texas Instruments LM324 Operational Amplifier MOD - UHF TV modulator UM1233-E36 CVBS - Composite color video output socket RGB - RGB monitor video output socket CASS - Cassette port PWR - 3-pin power input from internal power supply KBD_CONN - 22-pin keyboard connector SPKR - 2-pin internal speaker connector ****************************************************************************** Emulation notes: I don't have a real system to verify the behaviour of the emulation. The things that can be done through BASIC programs seem to behave properly (most of the time :). Incomplete: - Sound (sound is too high?) - Graphics (seems to be wrong for several games) - 1 MHz bus is not emulated - Bus claiming by ULA is not implemented ******************************************************************************/ #include "emu.h" #include "cpu/m6502/m6502.h" #include "includes/electron.h" #include "imagedev/cassette.h" #include "formats/uef_cas.h" #include "formats/csw_cas.h" #include "sound/beep.h" #include "screen.h" #include "softlist.h" #include "speaker.h" static const rgb_t electron_palette[8]= { rgb_t(0x0ff,0x0ff,0x0ff), rgb_t(0x000,0x0ff,0x0ff), rgb_t(0x0ff,0x000,0x0ff), rgb_t(0x000,0x000,0x0ff), rgb_t(0x0ff,0x0ff,0x000), rgb_t(0x000,0x0ff,0x000), rgb_t(0x0ff,0x000,0x000), rgb_t(0x000,0x000,0x000) }; void electron_state::electron_colours(palette_device &palette) const { palette.set_pen_colors(0, electron_palette); } void electron_state::electron_mem(address_map &map) { map(0x0000, 0x7fff).rw(FUNC(electron_state::electron_mem_r), FUNC(electron_state::electron_mem_w)); /* 32KB of RAM */ map(0x8000, 0xbfff).rw(FUNC(electron_state::electron_paged_r), FUNC(electron_state::electron_paged_w)); /* Banked ROM pages */ map(0xc000, 0xffff).rw(FUNC(electron_state::electron_mos_r), FUNC(electron_state::electron_mos_w)); /* OS ROM */ map(0xfc00, 0xfcff).rw(FUNC(electron_state::electron_fred_r), FUNC(electron_state::electron_fred_w)); /* FRED */ map(0xfd00, 0xfdff).rw(FUNC(electron_state::electron_jim_r), FUNC(electron_state::electron_jim_w)); /* JIM */ map(0xfe00, 0xfeff).rw(FUNC(electron_state::electron_sheila_r), FUNC(electron_state::electron_sheila_w)); /* SHEILA */ } void electron_state::electron64_opcodes(address_map &map) { map(0x0000, 0xffff).r(FUNC(electron_state::electron64_fetch_r)); } INPUT_CHANGED_MEMBER(electron_state::trigger_reset) { m_maincpu->set_input_line(INPUT_LINE_RESET, newval ? ASSERT_LINE : CLEAR_LINE); if (!newval) { m_exp->reset(); } } static INPUT_PORTS_START( electron ) PORT_START("LINE.0") PORT_BIT(0x01, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_NAME("\xE2\x86\x92 | \\") PORT_CODE(KEYCODE_BACKSLASH) PORT_CHAR(UCHAR_MAMEKEY(RIGHT)) PORT_CHAR('|') PORT_CHAR('\\') // on the real keyboard, this would be on the 1st row, the 3rd key after 0 PORT_BIT(0x02, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_NAME("COPY") PORT_CODE(KEYCODE_END) PORT_CHAR(UCHAR_MAMEKEY(F1)) PORT_CHAR('[') PORT_CHAR(']') PORT_BIT(0x04, IP_ACTIVE_HIGH, IPT_UNUSED) PORT_BIT(0x08, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_SPACE) PORT_CHAR(' ') PORT_START("LINE.1") PORT_BIT(0x01, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_NAME("\xE2\x86\x90 ^ ~") PORT_CODE(KEYCODE_EQUALS) PORT_CHAR(UCHAR_MAMEKEY(LEFT)) PORT_CHAR('^') PORT_CHAR('~') PORT_BIT(0x02, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_NAME("\xE2\x86\x93 _ }") PORT_CODE(KEYCODE_CLOSEBRACE) PORT_CHAR(UCHAR_MAMEKEY(DOWN)) PORT_CHAR('_') PORT_CHAR('}') PORT_BIT(0x04, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_NAME("RETURN") PORT_CODE(KEYCODE_ENTER) PORT_CHAR(13) PORT_BIT(0x08, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_NAME("DELETE") PORT_CODE(KEYCODE_BACKSPACE) PORT_CHAR(8) PORT_START("LINE.2") PORT_BIT(0x01, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_MINUS) PORT_CHAR('-') PORT_CHAR('=') PORT_BIT(0x02, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_NAME("\xE2\x86\x91 \xC2\xA3 {") PORT_CODE(KEYCODE_OPENBRACE) PORT_CHAR(UCHAR_MAMEKEY(UP)) PORT_CHAR(0xA3) PORT_CHAR('{') PORT_BIT(0x04, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_QUOTE) PORT_CHAR(':') PORT_CHAR('*') PORT_BIT(0x08, IP_ACTIVE_HIGH, IPT_UNUSED) PORT_START("LINE.3") PORT_BIT(0x01, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_0) PORT_CHAR('0') PORT_CHAR('@') PORT_BIT(0x02, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_P) PORT_CHAR('p') PORT_CHAR('P') PORT_BIT(0x04, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_COLON) PORT_CHAR(';') PORT_CHAR('+') PORT_BIT(0x08, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_SLASH) PORT_CHAR('/') PORT_CHAR('?') PORT_START("LINE.4") PORT_BIT(0x01, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_9) PORT_CHAR('9') PORT_CHAR(')') PORT_BIT(0x02, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_O) PORT_CHAR('o') PORT_CHAR('O') PORT_BIT(0x04, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_L) PORT_CHAR('l') PORT_CHAR('L') PORT_BIT(0x08, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_STOP) PORT_CHAR('.') PORT_CHAR('>') PORT_START("LINE.5") PORT_BIT(0x01, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_8) PORT_CHAR('8') PORT_CHAR('(') PORT_BIT(0x02, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_I) PORT_CHAR('i') PORT_CHAR('I') PORT_BIT(0x04, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_K) PORT_CHAR('k') PORT_CHAR('K') PORT_BIT(0x08, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_COMMA) PORT_CHAR(',') PORT_CHAR('<') PORT_START("LINE.6") PORT_BIT(0x01, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_7) PORT_CHAR('7') PORT_CHAR('\'') PORT_BIT(0x02, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_U) PORT_CHAR('u') PORT_CHAR('U') PORT_BIT(0x04, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_J) PORT_CHAR('j') PORT_CHAR('J') PORT_BIT(0x08, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_M) PORT_CHAR('m') PORT_CHAR('M') PORT_START("LINE.7") PORT_BIT(0x01, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_6) PORT_CHAR('6') PORT_CHAR('&') PORT_BIT(0x02, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_Y) PORT_CHAR('y') PORT_CHAR('Y') PORT_BIT(0x04, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_H) PORT_CHAR('h') PORT_CHAR('H') PORT_BIT(0x08, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_N) PORT_CHAR('n') PORT_CHAR('N') PORT_START("LINE.8") PORT_BIT(0x01, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_5) PORT_CHAR('5') PORT_CHAR('%') PORT_BIT(0x02, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_T) PORT_CHAR('t') PORT_CHAR('T') PORT_BIT(0x04, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_G) PORT_CHAR('g') PORT_CHAR('G') PORT_BIT(0x08, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_B) PORT_CHAR('b') PORT_CHAR('B') PORT_START("LINE.9") PORT_BIT(0x01, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_4) PORT_CHAR('4') PORT_CHAR('$') PORT_BIT(0x02, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_R) PORT_CHAR('r') PORT_CHAR('R') PORT_BIT(0x04, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_F) PORT_CHAR('f') PORT_CHAR('F') PORT_BIT(0x08, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_V) PORT_CHAR('v') PORT_CHAR('V') PORT_START("LINE.10") PORT_BIT(0x01, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_3) PORT_CHAR('3') PORT_CHAR('#') PORT_BIT(0x02, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_E) PORT_CHAR('e') PORT_CHAR('E') PORT_BIT(0x04, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_D) PORT_CHAR('d') PORT_CHAR('D') PORT_BIT(0x08, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_C) PORT_CHAR('c') PORT_CHAR('C') PORT_START("LINE.11") PORT_BIT(0x01, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_2) PORT_CHAR('2') PORT_CHAR('"') PORT_BIT(0x02, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_W) PORT_CHAR('w') PORT_CHAR('W') PORT_BIT(0x04, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_S) PORT_CHAR('s') PORT_CHAR('S') PORT_BIT(0x08, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_X) PORT_CHAR('x') PORT_CHAR('X') PORT_START("LINE.12") PORT_BIT(0x01, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_1) PORT_CHAR('1') PORT_CHAR('!') PORT_BIT(0x02, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_Q) PORT_CHAR('q') PORT_CHAR('Q') PORT_BIT(0x04, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_A) PORT_CHAR('a') PORT_CHAR('A') PORT_BIT(0x08, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_Z) PORT_CHAR('z') PORT_CHAR('Z') PORT_START("LINE.13") PORT_BIT(0x01, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_NAME("ESCAPE") PORT_CODE(KEYCODE_ESC) PORT_CHAR(UCHAR_MAMEKEY(ESC)) PORT_BIT(0x02, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_NAME("FUNC") PORT_CODE(KEYCODE_TAB) PORT_CHAR(UCHAR_MAMEKEY(LALT)) PORT_BIT(0x04, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_LCONTROL) PORT_CODE(KEYCODE_RCONTROL) PORT_CHAR(UCHAR_SHIFT_2) PORT_BIT(0x08, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_CODE(KEYCODE_RSHIFT) PORT_CODE(KEYCODE_LSHIFT) PORT_CHAR(UCHAR_SHIFT_1) PORT_START("BRK") /* BREAK */ PORT_BIT(0x01, IP_ACTIVE_HIGH, IPT_KEYBOARD) PORT_NAME("BREAK") PORT_CODE(KEYCODE_F12) PORT_CHAR(UCHAR_MAMEKEY(F12)) PORT_CHANGED_MEMBER(DEVICE_SELF, electron_state, trigger_reset, 0) INPUT_PORTS_END static INPUT_PORTS_START( electron64 ) PORT_INCLUDE(electron) PORT_START("MRB") PORT_CONFNAME(0x03, 0x02, "MRB Mode") PORT_CONFSETTING(0x00, "Normal") PORT_CONFSETTING(0x01, "Turbo") PORT_CONFSETTING(0x02, "64K") INPUT_PORTS_END void electron_state::electron(machine_config &config) { M6502(config, m_maincpu, 16_MHz_XTAL / 8); m_maincpu->set_addrmap(AS_PROGRAM, &electron_state::electron_mem); SCREEN(config, m_screen, SCREEN_TYPE_RASTER); m_screen->set_raw(16_MHz_XTAL, 1024, 0, 640, 312, 0, 256); //m_screen->set_raw(16_MHz_XTAL, 1024, 264, 264 + 640, 312, 31, 31 + 256) m_screen->set_screen_update(FUNC(electron_state::screen_update_electron)); m_screen->set_video_attributes(VIDEO_UPDATE_SCANLINE); m_screen->set_palette("palette"); PALETTE(config, "palette", FUNC(electron_state::electron_colours), 8); SPEAKER(config, "mono").front_center(); BEEP(config, m_beeper, 300).add_route(ALL_OUTPUTS, "mono", 1.00); RAM(config, m_ram).set_default_size("32K"); CASSETTE(config, m_cassette); m_cassette->set_formats(bbc_cassette_formats); m_cassette->set_default_state(CASSETTE_PLAY | CASSETTE_MOTOR_DISABLED); m_cassette->set_interface("electron_cass"); /* expansion port */ ELECTRON_EXPANSION_SLOT(config, m_exp, 16_MHz_XTAL, electron_expansion_devices, "plus3"); m_exp->irq_handler().set_inputline(m_maincpu, M6502_IRQ_LINE); m_exp->nmi_handler().set_inputline(m_maincpu, M6502_NMI_LINE); /* software lists */ SOFTWARE_LIST(config, "cass_list").set_original("electron_cass"); SOFTWARE_LIST(config, "cart_list").set_original("electron_cart"); SOFTWARE_LIST(config, "flop_list").set_original("electron_flop"); SOFTWARE_LIST(config, "rom_list").set_original("electron_rom"); } void electron_state::btm2105(machine_config &config) { electron(config); m_screen->set_color(rgb_t::amber()); /* expansion port */ m_exp->set_default_option("m2105"); m_exp->set_fixed(true); /* software lists */ config.device_remove("cass_list"); config.device_remove("cart_list"); config.device_remove("flop_list"); config.device_remove("rom_list"); } void electron_state::electron64(machine_config &config) { electron(config); m_maincpu->set_addrmap(AS_PROGRAM, &electron_state::electron_mem); m_maincpu->set_addrmap(AS_OPCODES, &electron_state::electron64_opcodes); m_ram->set_default_size("64K"); } ROM_START(electron) ROM_REGION( 0x4000, "mos", 0 ) ROM_LOAD( "b02_acornos-1.rom", 0x0000, 0x4000, CRC(a0c2cf43) SHA1(a27ce645472cc5497690e4bfab43710efbb0792d) ) ROM_REGION( 0x4000, "basic", 0 ) ROM_LOAD( "basic.rom", 0x0000, 0x4000, CRC(79434781) SHA1(4a7393f3a45ea309f744441c16723e2ef447a281) ) ROM_END ROM_START(electront) ROM_REGION( 0x4000, "mos", 0 ) /* Serial 06-ALA01-0000087 from Centre for Computing History */ ROM_LOAD( "elk_036.rom", 0x0000, 0x4000, CRC(dd1a99c3) SHA1(87ee1b14895e476909dd002d5ca2346a3a5f3f57) ) ROM_REGION( 0x4000, "basic", 0 ) ROM_LOAD( "basic.rom", 0x0000, 0x4000, CRC(79434781) SHA1(4a7393f3a45ea309f744441c16723e2ef447a281) ) ROM_END ROM_START(electron64) ROM_REGION( 0x4000, "mos", 0 ) ROM_LOAD( "os_300.rom", 0x0000, 0x4000, CRC(f80a0cea) SHA1(165e42ff4164a842e56f08ebd420d5027af99fdd) ) ROM_REGION(0x4000, "basic", 0) ROM_LOAD( "basic.rom", 0x0000, 0x4000, CRC(79434781) SHA1(4a7393f3a45ea309f744441c16723e2ef447a281) ) ROM_END #define rom_btm2105 rom_electron /* YEAR NAME PARENT COMPAT MACHINE INPUT CLASS INIT COMPANY FULLNAME FLAGS */ COMP ( 1983, electron, 0, 0, electron, electron, electron_state, empty_init, "Acorn", "Acorn Electron", MACHINE_IMPERFECT_SOUND | MACHINE_IMPERFECT_GRAPHICS ) COMP ( 1983, electront, electron, 0, electron, electron, electron_state, empty_init, "Acorn", "Acorn Electron (Trial)", MACHINE_IMPERFECT_SOUND | MACHINE_IMPERFECT_GRAPHICS ) COMP ( 1985, btm2105, electron, 0, btm2105, electron, electron_state, empty_init, "British Telecom Business Systems", "BT Merlin M2105", MACHINE_NOT_WORKING ) COMP ( 1987, electron64, electron, 0, electron64, electron64, electron_state, empty_init, "Acorn/Slogger", "Acorn Electron (64K Master RAM Board)", MACHINE_IMPERFECT_SOUND | MACHINE_IMPERFECT_GRAPHICS )