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https://github.com/holub/mame
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bus/electron: Added a homebrew 68000 second processor.
This commit is contained in:
Nigel Barnes
parent
807430ad46
commit
8db344fcc5
@ -1104,6 +1104,8 @@ if (BUSES["ELECTRON"]~=null) then
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MAME_DIR .. "src/devices/bus/electron/fbjoy.h",
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MAME_DIR .. "src/devices/bus/electron/fbprint.cpp",
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MAME_DIR .. "src/devices/bus/electron/fbprint.h",
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MAME_DIR .. "src/devices/bus/electron/mc68k.cpp",
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MAME_DIR .. "src/devices/bus/electron/mc68k.h",
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MAME_DIR .. "src/devices/bus/electron/mode7.cpp",
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MAME_DIR .. "src/devices/bus/electron/mode7.h",
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MAME_DIR .. "src/devices/bus/electron/plus1.cpp",
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@ -101,6 +101,7 @@ void electron_expansion_slot_device::expbus_w(offs_t offset, uint8_t data)
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// slot devices
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#include "fbjoy.h"
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#include "fbprint.h"
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#include "mc68k.h"
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#include "mode7.h"
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//#include "lebox.h"
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#include "plus1.h"
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@ -120,6 +121,7 @@ void electron_expansion_devices(device_slot_interface &device)
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device.option_add("ap6", ELECTRON_AP6);
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device.option_add("fbjoy", ELECTRON_FBJOY);
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device.option_add("fbprint", ELECTRON_FBPRINT);
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device.option_add("mc68k", ELECTRON_MC68K);
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device.option_add("mode7", ELECTRON_MODE7);
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//device.option_add("lebox", ELECTRON_LEBOX);
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device.option_add("plus1", ELECTRON_PLUS1);
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243
src/devices/bus/electron/mc68k.cpp
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243
src/devices/bus/electron/mc68k.cpp
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@ -0,0 +1,243 @@
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// license:BSD-3-Clause
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// copyright-holders:Nigel Barnes
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/**********************************************************************
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Electron 68000 Expansion
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This is a homebrew 68000 second processor for the Electron from around 1990.
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Commands:
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*FX29 - sends a short stub to the 68000 which tells it to:
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(a) start the 68000 OS in ROM now.
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(b) start the 68000 OS on every reset from now on, until the next
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CTRL+BREAK or power cycle.
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*FX28 - tells sideways bank 12 to make itself the current language ROM on the
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6502, and the language entry point tells the 68000 to start the BASIC
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interpreter in ROM, but the 68000 OS has to be currently running.
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BREAK will restart the current language ROM, so will restart 68000 BASIC.
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CTRL+BREAK will go back to 6502 BASIC as the language ROM.
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Usage notes:
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- to enter 68000 BASIC do *FX29, then *FX28, then BREAK.
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- to start the word processor, do CALL&407000 from the 68000 BASIC prompt.
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- to use the assembler, type your assembly code in as a BASIC program, with
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instruction mnemonics in lower case. Set D% to where in RAM you want the
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object code stored and P% to 2, then CALL&401C8C.
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**********************************************************************/
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#include "emu.h"
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#include "mc68k.h"
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#include "machine/6522via.h"
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#include "machine/6850acia.h"
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#include "machine/clock.h"
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#include "machine/input_merger.h"
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//**************************************************************************
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// DEVICE DEFINITIONS
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//**************************************************************************
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DEFINE_DEVICE_TYPE(ELECTRON_MC68K, electron_mc68k_device, "electron_mc68k", "Electron 68000 Expansion")
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//-------------------------------------------------
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// ADDRESS_MAP( mem_map )
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//-------------------------------------------------
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void electron_mc68k_device::mem_map(address_map &map)
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{
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map(0x000000, 0x00ffff).ram();
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map(0x400000, 0x40ffff).rom().region("main_rom", 0);
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map(0x800000, 0x800fff).rom().region("boot_rom", 0);
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map(0xff8000, 0xff801f).rw("via", FUNC(via6522_device::read), FUNC(via6522_device::write)).umask16(0xff00);
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map(0xff8020, 0xff803f).rw(m_pia[0], FUNC(pia6821_device::read), FUNC(pia6821_device::write)).umask16(0xff00);
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map(0xff8040, 0xff805f).rw("acia", FUNC(acia6850_device::read), FUNC(acia6850_device::write)).umask16(0xff00);
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}
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//-------------------------------------------------
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// ROM( mc68k )
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//-------------------------------------------------
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ROM_START( mc68k )
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ROM_REGION(0x8000, "exp_rom", 0)
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ROM_LOAD("elk68k_lower.bin", 0x0000, 0x4000, CRC(6e18f9fb) SHA1(31d228e4b6be18c51dd6a0c42c9e6e1e507decc6))
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ROM_LOAD("elk68k_upper.bin", 0x4000, 0x4000, CRC(0c960571) SHA1(cf3a060fee7ac23128d9e4657790d218681e6e61))
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ROM_REGION16_BE(0x1000, "boot_rom", ROMREGION_ERASE00)
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ROM_LOAD("68kboot.bin", 0x0000, 0x0100, CRC(5855ef60) SHA1(76165ee0f34a24fd2a908987fd5f05e23ea75677))
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ROM_REGION16_BE(0x10000, "main_rom", ROMREGION_ERASE00)
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ROM_LOAD("68kmain.bin", 0x0000, 0x10000, CRC(4d7a9e4f) SHA1(90afb5910995511ae943ad62ea2967eff85e8ef7))
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ROM_END
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//-------------------------------------------------
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// device_add_mconfig - add device configuration
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//-------------------------------------------------
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void electron_mc68k_device::device_add_mconfig(machine_config &config)
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{
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M68000(config, m_maincpu, 10_MHz_XTAL);
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m_maincpu->set_addrmap(AS_PROGRAM, &electron_mc68k_device::mem_map);
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m_maincpu->disable_interrupt_mixer();
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INPUT_MERGER_ANY_HIGH(config, "irq_ipl0").output_handler().set_inputline(m_maincpu, M68K_IRQ_IPL0);
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INPUT_MERGER_ANY_HIGH(config, "irq_ipl1").output_handler().set_inputline(m_maincpu, M68K_IRQ_IPL1);
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INPUT_MERGER_ANY_HIGH(config, "irq_exp").output_handler().set(DEVICE_SELF_OWNER, FUNC(electron_expansion_slot_device::irq_w));
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RAM(config, m_ram).set_default_size("256K").set_extra_options("64K,128K,192K");
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PIA6821(config, m_pia[0], 0);
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m_pia[0]->writepb_handler().set(m_pia[1], FUNC(pia6821_device::set_a_input));
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m_pia[0]->ca2_handler().set(m_pia[1], FUNC(pia6821_device::cb1_w));
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m_pia[0]->cb2_handler().set(m_pia[1], FUNC(pia6821_device::ca1_w));
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m_pia[0]->irqa_handler().set("irq_ipl0", FUNC(input_merger_device::in_w<0>));
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m_pia[0]->irqb_handler().set("irq_ipl0", FUNC(input_merger_device::in_w<1>));
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PIA6821(config, m_pia[1], 0);
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m_pia[1]->writepb_handler().set(m_pia[0], FUNC(pia6821_device::set_a_input));
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m_pia[1]->ca2_handler().set(m_pia[0], FUNC(pia6821_device::cb1_w));
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m_pia[1]->cb2_handler().set(m_pia[0], FUNC(pia6821_device::ca1_w));
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m_pia[1]->irqa_handler().set("irq_exp", FUNC(input_merger_device::in_w<0>));
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m_pia[1]->irqb_handler().set("irq_exp", FUNC(input_merger_device::in_w<1>));
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via6522_device &via(MOS6522(config, "via", 10_MHz_XTAL / 10));
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via.irq_handler().set("irq_ipl1", FUNC(input_merger_device::in_w<0>));
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acia6850_device &acia(ACIA6850(config, "acia", 0));
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acia.irq_handler().set("irq_ipl1", FUNC(input_merger_device::in_w<1>));
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clock_device &acia_clock(CLOCK(config, "acia_clock", 3.6864_MHz_XTAL / 12));
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acia_clock.signal_handler().set("acia", FUNC(acia6850_device::write_txc));
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acia_clock.signal_handler().append("acia", FUNC(acia6850_device::write_rxc));
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}
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const tiny_rom_entry *electron_mc68k_device::device_rom_region() const
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{
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return ROM_NAME( mc68k );
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}
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//**************************************************************************
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// LIVE DEVICE
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//**************************************************************************
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//-------------------------------------------------
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// electron_mc68k_device - constructor
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//-------------------------------------------------
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electron_mc68k_device::electron_mc68k_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock)
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: device_t(mconfig, ELECTRON_MC68K, tag, owner, clock)
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, device_electron_expansion_interface(mconfig, *this)
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, m_maincpu(*this, "maincpu")
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, m_ram(*this, RAM_TAG)
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, m_pia(*this, "pia%u", 0U)
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, m_boot_rom(*this, "boot_rom")
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, m_exp_rom(*this, "exp_rom")
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, m_romsel(0)
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{
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}
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//-------------------------------------------------
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// device_start - device-specific startup
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//-------------------------------------------------
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void electron_mc68k_device::device_start()
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{
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save_item(NAME(m_romsel));
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}
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//-------------------------------------------------
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// device_reset - device-specific reset
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//-------------------------------------------------
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void electron_mc68k_device::device_reset()
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{
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address_space &program = m_maincpu->space(AS_PROGRAM);
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// address map during booting
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program.install_rom(0x0000, 0x0fff, m_boot_rom->base());
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m_rom_shadow_tap = program.install_read_tap(0x800000, 0xffffff, "rom_shadow_r", [this](offs_t offset, u16 &data, u16 mem_mask)
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{
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if (!machine().side_effects_disabled())
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{
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// delete this tap
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m_rom_shadow_tap->remove();
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// address map after booting
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m_maincpu->space(AS_PROGRAM).install_ram(0x000000, m_ram->mask(), m_ram->pointer());
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}
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// return the original data
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return data;
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});
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}
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//-------------------------------------------------
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// expbus_r - expansion data read
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//-------------------------------------------------
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u8 electron_mc68k_device::expbus_r(offs_t offset)
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{
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u8 data = 0xff;
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switch (offset >> 12)
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{
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case 0x8: case 0x9: case 0xa: case 0xb:
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switch (m_romsel)
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{
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case 12:
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data = m_exp_rom->base()[0x0000 | (offset & 0x3fff)];
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break;
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case 13:
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data = m_exp_rom->base()[0x4000 | (offset & 0x3fff)];
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break;
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}
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break;
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case 0xf:
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switch (offset >> 8)
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{
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case 0xfd:
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switch (offset & 0xf8)
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{
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case 0x80:
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data = m_pia[1]->read_alt(offset);
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break;
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}
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break;
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}
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}
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return data;
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}
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//-------------------------------------------------
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// expbus_w - expansion data write
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//-------------------------------------------------
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void electron_mc68k_device::expbus_w(offs_t offset, u8 data)
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{
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switch (offset >> 8)
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{
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case 0xfd:
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switch (offset & 0xf8)
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{
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case 0x80:
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m_pia[1]->write_alt(offset, data);
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break;
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}
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break;
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case 0xfe:
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if (offset == 0xfe05)
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{
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m_romsel = data & 0x0f;
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}
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break;
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}
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}
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63
src/devices/bus/electron/mc68k.h
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63
src/devices/bus/electron/mc68k.h
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@ -0,0 +1,63 @@
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// license:BSD-3-Clause
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// copyright-holders:Nigel Barnes
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/**********************************************************************
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Electron 68000 Expansion
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**********************************************************************/
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#ifndef MAME_BUS_ELECTRON_MC68K_M
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#define MAME_BUS_ELECTRON_MC68K_M
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#pragma once
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#include "exp.h"
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#include "cpu/m68000/m68000.h"
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#include "machine/6821pia.h"
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#include "machine/ram.h"
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//**************************************************************************
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// TYPE DEFINITIONS
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//**************************************************************************
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class electron_mc68k_device:
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public device_t,
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public device_electron_expansion_interface
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{
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public:
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// construction/destruction
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electron_mc68k_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock);
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protected:
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// device-level overrides
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virtual void device_start() override;
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virtual void device_reset() override;
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// optional information overrides
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virtual void device_add_mconfig(machine_config &config) override;
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virtual const tiny_rom_entry *device_rom_region() const override;
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virtual u8 expbus_r(offs_t offset) override;
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virtual void expbus_w(offs_t offset, u8 data) override;
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private:
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required_device<m68000_base_device> m_maincpu;
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required_device<ram_device> m_ram;
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required_device_array<pia6821_device, 2> m_pia;
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required_memory_region m_boot_rom;
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required_memory_region m_exp_rom;
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memory_passthrough_handler *m_rom_shadow_tap;
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void mem_map(address_map &map);
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u8 m_romsel;
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};
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// device type definition
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DECLARE_DEVICE_TYPE(ELECTRON_MC68K, electron_mc68k_device)
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#endif // MAME_BUS_ELECTRON_MC68K_M
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