// license:BSD-3-Clause
// copyright-holders:Wilbert Pol, Nigel Barnes
/******************************************************************************
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
Master RAM Board
----------------
The Master RAM Board (MRB) is an internal expansion board from Slogger, and could
also be purchased pre-fitted in the form of the Electron 64.
The MRB comes with a new MOS which provides three modes of operation, selected by a
switch, which are Normal, Turbo, and 64K. The 64K mode was the first to provide a
'shadow mode' on the Electron.
Stop Press 64i
--------------
The Stop Press 64i (SP64i) is another internal expansion board from Slogger, which
also requires the MRB to fitted. Being released in the early 90's there are no known
working examples, but bare prototype boards and ROMs were discovered during a Slogger
workshop clearout.
It provides a re-written AMX Stop Press (Desktop Publishing) for the Electron to take
advantage of the extra memory provided by the Master RAM Board, and also offers
ROM/RAM sockets and User Port for a mouse.
******************************************************************************
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
Other internal boards to emulate:
- Slogger Turbo Driver
- Jafa Mode7 Mk2 Display Unit
- move MRB and SP64i to an internal slot device?
******************************************************************************/
#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
static INPUT_PORTS_START(electronsp)
PORT_INCLUDE(electron64)
PORT_START("ROMPAGES")
/* TODO: Actual 4bit dip settings are unknown, require a manual */
PORT_DIPNAME(0x0f, 0x06, "SP64i ROM Pages")
PORT_DIPSETTING(0x00, "0&1")
PORT_DIPSETTING(0x02, "2&3")
PORT_DIPSETTING(0x04, "4&5")
PORT_DIPSETTING(0x06, "6&7")
PORT_DIPSETTING(0x08, "8&9 (reserved)")
PORT_DIPSETTING(0x0a, "10&11 (reserved)")
PORT_DIPSETTING(0x0c, "12&13")
PORT_DIPSETTING(0x0e, "14&15")
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);
INPUT_MERGER_ANY_HIGH(config, m_irqs).output_handler().set_inputline(m_maincpu, M6502_IRQ_LINE);
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(m_irqs, FUNC(input_merger_device::in_w<1>));
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");
}
void electronsp_state::electronsp(machine_config &config)
{
/* install mrb board */
electron64(config);
/* rom sockets */
GENERIC_SOCKET(config, m_romi[0], generic_plain_slot, "electron_rom", "bin,rom");
m_romi[0]->set_device_load(FUNC(electronsp_state::rom1_load));
GENERIC_SOCKET(config, m_romi[1], generic_plain_slot, "electron_rom", "bin,rom");
m_romi[1]->set_device_load(FUNC(electronsp_state::rom2_load));
/* via */
VIA6522(config, m_via, 16_MHz_XTAL / 16);
m_via->readpb_handler().set(m_userport, FUNC(bbc_userport_slot_device::pb_r));
m_via->writepb_handler().set(m_userport, FUNC(bbc_userport_slot_device::pb_w));
m_via->irq_handler().set(m_irqs, FUNC(input_merger_device::in_w<2>));
/* user port */
BBC_USERPORT_SLOT(config, m_userport, bbc_userport_devices, "amxmouse");
m_userport->cb1_handler().set(m_via, FUNC(via6522_device::write_cb1));
m_userport->cb2_handler().set(m_via, FUNC(via6522_device::write_cb2));
}
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
ROM_START(electronsp)
ROM_REGION( 0x4000, "mos", 0 )
ROM_LOAD( "os_310.rom", 0x0000, 0x4000, CRC(8b7a9003) SHA1(6d4e2f8ddc1d829b14206d2747749c4c24789568) )
ROM_REGION( 0x4000, "basic", 0 )
ROM_LOAD( "basic.rom", 0x0000, 0x4000, CRC(79434781) SHA1(4a7393f3a45ea309f744441c16723e2ef447a281) )
ROM_REGION( 0x8000, "sp64", 0 )
ROM_SYSTEM_BIOS( 0, "101_2", "v1.01 (2x16K)" )
ROMX_LOAD( "sp64_101_1.rom", 0x0000, 0x4000, CRC(07e2c5d6) SHA1(837e3382c376e3cc1ae42f1ca51158657ef2fd73), ROM_BIOS(0) )
ROMX_LOAD( "sp64_101_2.rom", 0x4000, 0x4000, CRC(3d0e5dc1) SHA1(89743c43b24950d481c150fd4b4de985600cca2d), ROM_BIOS(0) )
ROM_SYSTEM_BIOS( 1, "100", "v1.00 (32K)" )
ROMX_LOAD( "sp64_100.rom", 0x0000, 0x8000, CRC(4918221c) SHA1(f185873106e7e7225b2e0c718803dc1ec4ebc685), ROM_BIOS(1) )
ROM_SYSTEM_BIOS( 2, "100_2", "v1.00 (2x16K)" )
ROMX_LOAD( "sp64_100_1.rom", 0x0000, 0x4000, CRC(6053e5a0) SHA1(6d79e5494349f157672e7c59949f3941e5a3dbdb), ROM_BIOS(2) )
ROMX_LOAD( "sp64_100_2.rom", 0x4000, 0x4000, CRC(25d11d8e) SHA1(c1bceeb50fee1e11de7505a3b664b844cfb56289), ROM_BIOS(2) )
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 Computers", "Acorn Electron", MACHINE_IMPERFECT_SOUND | MACHINE_IMPERFECT_GRAPHICS | MACHINE_SUPPORTS_SAVE )
COMP ( 1983, electront, electron, 0, electron, electron, electron_state, empty_init, "Acorn Computers", "Acorn Electron (Trial)", MACHINE_IMPERFECT_SOUND | MACHINE_IMPERFECT_GRAPHICS | MACHINE_SUPPORTS_SAVE )
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 Computers / Slogger", "Acorn Electron (64K Master RAM Board)", MACHINE_IMPERFECT_SOUND | MACHINE_IMPERFECT_GRAPHICS | MACHINE_SUPPORTS_SAVE )
COMP ( 1991, electronsp, electron, 0, electronsp, electronsp, electronsp_state, empty_init, "Acorn Computers / Slogger", "Acorn Electron (Stop Press 64i)", MACHINE_IMPERFECT_SOUND | MACHINE_IMPERFECT_GRAPHICS | MACHINE_SUPPORTS_SAVE )