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Diffstat (limited to 'src/devices/bus/a2bus/a2bus.cpp')
-rw-r--r-- | src/devices/bus/a2bus/a2bus.cpp | 334 |
1 files changed, 334 insertions, 0 deletions
diff --git a/src/devices/bus/a2bus/a2bus.cpp b/src/devices/bus/a2bus/a2bus.cpp new file mode 100644 index 00000000000..cd2eab4eea7 --- /dev/null +++ b/src/devices/bus/a2bus/a2bus.cpp @@ -0,0 +1,334 @@ +// license:BSD-3-Clause +// copyright-holders:R. Belmont +/*************************************************************************** + + a2bus.c - Apple II slot bus and card emulation + + by R. Belmont + + Pinout (/ indicates an inverted signal, ie, one that would have a bar over it + on a schematic diagram) + + (rear of computer) + + GND 26 25 +5V + DMA IN 27 24 DMA OUT + INT IN 28 23 INT OUT + /NMI 29 22 /DMA + /IRQ 30 21 RDY + /RES 31 20 /IOSTB + /INH 32 19 N.C. + -12V 33 18 R/W + -5V 34 17 A15 + N.C. 35 16 A14 + 7M 36 15 A13 + Q3 37 14 A12 + PH1 38 13 A11 + USER 1 39 12 A10 + PH0 40 11 A9 + /DEVSEL 41 10 A8 + D7 42 9 A7 + D6 43 8 A6 + D5 44 7 A5 + D4 45 6 A4 + D3 46 5 A3 + D2 47 4 A2 + D1 48 3 A1 + D0 49 2 A0 + -12V 50 1 /IOSEL + + (front of computer) + + Signal descriptions: + GND - power supply ground + DMA IN - daisy chain of DMA signal from higher priority devices. usually connected to DMA OUT. + INT IN - similar to DMA IN but for INT instead of DMA. + /NMI - non-maskable interrupt input to the 6502 + /IRQ - maskable interrupt input to the 6502 + /RES - system reset signal + /INH - On the II and II+, inhibits the motherboard ROMs, allowing a card to replace them. + On the IIe, inhibits all motherboard RAM/ROM for both CPU and DMA accesses. + On the IIgs, works like the IIe except for the address range 0x6000 to 0x9FFF where + it will cause bus contention. + -12V - negative 12 volts DC power + -5V - negative 5 volts DC power + 7M - 7 MHz clock (1/4th of the master clock on the IIgs, 1/2 on 8-bit IIs) + Q3 - 2 MHz asymmetrical clock + PH1 - 6502 phase 1 clock + /DEVSEL - asserted on an access to C0nX, where n = the slot number plus 8. + D0-D7 - 8-bit data bus + +5V - 5 volts DC power + DMA OUT - see DMA IN + INT OUT - see INT IN + /DMA - pulling this low disconnects the 6502 from the bus and halts it + RDY - 6502 RDY input. Pulling this low when PH1 is active will halt the + 6502 and latch the current address bus value. + /IOSTB - asserted on an access between C800 and CFFF. + A0-A15 - 16-bit address bus + /IOSEL - asserted on accesses to CnXX where n is the slot number. + Not present on slot 0. + +***************************************************************************/ + +#include "emu.h" +#include "emuopts.h" +#include "a2bus.h" + + +//************************************************************************** +// GLOBAL VARIABLES +//************************************************************************** + +const device_type A2BUS_SLOT = &device_creator<a2bus_slot_device>; + +//************************************************************************** +// LIVE DEVICE +//************************************************************************** + +//------------------------------------------------- +// a2bus_slot_device - constructor +//------------------------------------------------- +a2bus_slot_device::a2bus_slot_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock) : + device_t(mconfig, A2BUS_SLOT, "Apple II Slot", tag, owner, clock, "a2bus_slot", __FILE__), + device_slot_interface(mconfig, *this) +{ +} + +a2bus_slot_device::a2bus_slot_device(const machine_config &mconfig, device_type type, const char *name, const char *tag, device_t *owner, UINT32 clock, const char *shortname, const char *source) : + device_t(mconfig, type, name, tag, owner, clock, shortname, source), + device_slot_interface(mconfig, *this) +{ +} + +void a2bus_slot_device::static_set_a2bus_slot(device_t &device, const char *tag, const char *slottag) +{ + a2bus_slot_device &a2bus_card = dynamic_cast<a2bus_slot_device &>(device); + a2bus_card.m_a2bus_tag = tag; + a2bus_card.m_a2bus_slottag = slottag; +} + +//------------------------------------------------- +// device_start - device-specific startup +//------------------------------------------------- + +void a2bus_slot_device::device_start() +{ + device_a2bus_card_interface *dev = dynamic_cast<device_a2bus_card_interface *>(get_card_device()); + + if (dev) device_a2bus_card_interface::static_set_a2bus_tag(*dev, m_a2bus_tag, m_a2bus_slottag); +} + +//************************************************************************** +// GLOBAL VARIABLES +//************************************************************************** + +const device_type A2BUS = &device_creator<a2bus_device>; + +void a2bus_device::static_set_cputag(device_t &device, const char *tag) +{ + a2bus_device &a2bus = downcast<a2bus_device &>(device); + a2bus.m_cputag = tag; +} + +//************************************************************************** +// LIVE DEVICE +//************************************************************************** + +//------------------------------------------------- +// a2bus_device - constructor +//------------------------------------------------- + +a2bus_device::a2bus_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock) : + device_t(mconfig, A2BUS, "Apple II Bus", tag, owner, clock, "a2bus", __FILE__), + m_out_irq_cb(*this), + m_out_nmi_cb(*this), + m_out_inh_cb(*this) +{ +} + +a2bus_device::a2bus_device(const machine_config &mconfig, device_type type, const char *name, const char *tag, device_t *owner, UINT32 clock, const char *shortname, const char *source) : + device_t(mconfig, type, name, tag, owner, clock, shortname, source), + m_out_irq_cb(*this), + m_out_nmi_cb(*this), + m_out_inh_cb(*this) +{ +} +//------------------------------------------------- +// device_start - device-specific startup +//------------------------------------------------- + +void a2bus_device::device_start() +{ + m_maincpu = machine().device<cpu_device>(m_cputag); + m_maincpu_space = &machine().device<cpu_device>(m_cputag)->space(AS_PROGRAM); + + // resolve callbacks + m_out_irq_cb.resolve_safe(); + m_out_nmi_cb.resolve_safe(); + m_out_inh_cb.resolve_safe(); + + // clear slots + for (int i = 0; i < 8; i++) + { + m_device_list[i] = NULL; + } + + m_slot_irq_mask = m_slot_nmi_mask = 0; +} + +//------------------------------------------------- +// device_reset - device-specific reset +//------------------------------------------------- + +void a2bus_device::device_reset() +{ +} + +device_a2bus_card_interface *a2bus_device::get_a2bus_card(int slot) +{ + if (slot < 0) + { + return NULL; + } + + if (m_device_list[slot]) + { + return m_device_list[slot]; + } + + return NULL; +} + +void a2bus_device::add_a2bus_card(int slot, device_a2bus_card_interface *card) +{ + m_device_list[slot] = card; +} + +UINT8 a2bus_device::get_a2bus_irq_mask() +{ + return m_slot_irq_mask; +} + +UINT8 a2bus_device::get_a2bus_nmi_mask() +{ + return m_slot_nmi_mask; +} + +void a2bus_device::set_irq_line(int state, int slot) +{ + m_out_irq_cb(state); + + if (state == CLEAR_LINE) + { + m_slot_irq_mask &= ~(1<<slot); + } + else if (state == ASSERT_LINE) + { + m_slot_irq_mask |= (1<<slot); + } +} + +void a2bus_device::set_nmi_line(int state, int slot) +{ + m_out_nmi_cb(state); + + if (state == CLEAR_LINE) + { + m_slot_nmi_mask &= ~(1<<slot); + } + else if (state == ASSERT_LINE) + { + m_slot_nmi_mask |= (1<<slot); + } +} + +void a2bus_device::set_maincpu_halt(int state) +{ + m_maincpu->set_input_line(INPUT_LINE_HALT, state); +} + +UINT8 a2bus_device::dma_r(address_space &space, UINT16 offset) +{ + m_maincpu_space->set_debugger_access(space.debugger_access()); + + return m_maincpu_space->read_byte(offset); +} + +void a2bus_device::dma_w(address_space &space, UINT16 offset, UINT8 data) +{ + m_maincpu_space->set_debugger_access(space.debugger_access()); + + m_maincpu_space->write_byte(offset, data); +} + +UINT8 a2bus_device::dma_nospace_r(UINT16 offset) +{ + return m_maincpu_space->read_byte(offset); +} + +void a2bus_device::dma_nospace_w(UINT16 offset, UINT8 data) +{ + m_maincpu_space->write_byte(offset, data); +} + +void a2bus_device::recalc_inh(int slot) +{ + m_out_inh_cb(ASSERT_LINE); + m_out_inh_cb(CLEAR_LINE); +} + +// interrupt request from a2bus card +WRITE_LINE_MEMBER( a2bus_device::irq_w ) { m_out_irq_cb(state); } +WRITE_LINE_MEMBER( a2bus_device::nmi_w ) { m_out_nmi_cb(state); } + +//************************************************************************** +// DEVICE CONFIG A2BUS CARD INTERFACE +//************************************************************************** + + +//************************************************************************** +// DEVICE A2BUS CARD INTERFACE +//************************************************************************** + +//------------------------------------------------- +// device_a2bus_card_interface - constructor +//------------------------------------------------- + +device_a2bus_card_interface::device_a2bus_card_interface(const machine_config &mconfig, device_t &device) + : device_slot_card_interface(mconfig, device), + m_a2bus(NULL), + m_a2bus_tag(NULL) +{ +} + + +//------------------------------------------------- +// ~device_a2bus_card_interface - destructor +//------------------------------------------------- + +device_a2bus_card_interface::~device_a2bus_card_interface() +{ +} + +void device_a2bus_card_interface::static_set_a2bus_tag(device_t &device, const char *tag, const char *slottag) +{ + device_a2bus_card_interface &a2bus_card = dynamic_cast<device_a2bus_card_interface &>(device); + a2bus_card.m_a2bus_tag = tag; + a2bus_card.m_a2bus_slottag = slottag; +} + +void device_a2bus_card_interface::set_a2bus_device() +{ + // extract the slot number from the last digit of the slot tag + int tlen = strlen(m_a2bus_slottag); + + m_slot = (m_a2bus_slottag[tlen-1] - '0'); + + if (m_slot < 0 || m_slot > 7) + { + fatalerror("Slot %x out of range for Apple II Bus\n", m_slot); + } + + m_a2bus = dynamic_cast<a2bus_device *>(device().machine().device(m_a2bus_tag)); + m_a2bus->add_a2bus_card(m_slot, this); +} |