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/***************************************************************************
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);
// 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;
}
}
//-------------------------------------------------
// 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;
}
void a2bus_device::set_irq_line(int state)
{
m_out_irq_cb(state);
}
void a2bus_device::set_nmi_line(int state)
{
m_out_nmi_cb(state);
}
void a2bus_device::set_inh_slotnum(int slot)
{
m_out_inh_cb(slot);
}
// 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);
}
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