// license:BSD-3-Clause
// copyright-holders:Curt Coder
/***************************************************************************
Zilog Z80 Parallel Input/Output Controller implementation
***************************************************************************/
/*
TODO:
- if port A is bidirectional, port B does not issue interrupts in bit mode
*/
#include "emu.h"
#include "z80pio.h"
//**************************************************************************
// CONSTANTS
//**************************************************************************
#define LOG 0
//**************************************************************************
// LIVE DEVICE
//**************************************************************************
// device type definition
DEFINE_DEVICE_TYPE(Z80PIO, z80pio_device, "z80pio", "Z80 PIO")
//-------------------------------------------------
// z80pio_device - constructor
//-------------------------------------------------
z80pio_device::z80pio_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) :
device_t(mconfig, Z80PIO, tag, owner, clock),
device_z80daisy_interface(mconfig, *this),
m_out_int_cb(*this),
m_in_pa_cb(*this),
m_out_pa_cb(*this),
m_out_ardy_cb(*this),
m_in_pb_cb(*this),
m_out_pb_cb(*this),
m_out_brdy_cb(*this)
{
}
//-------------------------------------------------
// device_start - device-specific startup
//-------------------------------------------------
void z80pio_device::device_start()
{
m_port[PORT_A].start(this, PORT_A);
m_port[PORT_B].start(this, PORT_B);
// resolve callbacks
m_out_int_cb.resolve_safe();
m_in_pa_cb.resolve_safe(0);
m_out_pa_cb.resolve_safe();
m_out_ardy_cb.resolve_safe();
m_in_pb_cb.resolve_safe(0);
m_out_pb_cb.resolve_safe();
m_out_brdy_cb.resolve_safe();
}
//-------------------------------------------------
// device_reset - device-specific reset
//-------------------------------------------------
void z80pio_device::device_reset()
{
// loop over ports
for (int index = PORT_A; index < PORT_COUNT; index++)
m_port[index].reset();
}
//**************************************************************************
// DAISY CHAIN INTERFACE
//**************************************************************************
//-------------------------------------------------
// z80daisy_irq_state - return the overall IRQ
// state for this device
//-------------------------------------------------
int z80pio_device::z80daisy_irq_state()
{
int state = 0;
for (int index = PORT_A; index < PORT_COUNT; index++)
{
pio_port &port = m_port[index];
if (port.m_ius)
{
// interrupt under service
return Z80_DAISY_IEO;
}
else if (port.m_ie && port.m_ip)
{
// interrupt pending
state = Z80_DAISY_INT;
}
}
return state;
}
//-------------------------------------------------
// z80daisy_irq_ack - acknowledge an IRQ and
// return the appropriate vector
//-------------------------------------------------
int z80pio_device::z80daisy_irq_ack()
{
for (int index = PORT_A; index < PORT_COUNT; index++)
{
pio_port &port = m_port[index];
if (port.m_ip)
{
if (LOG) logerror("Z80PIO Port %c Interrupt Acknowledge\n", 'A' + index);
// clear interrupt pending flag
port.m_ip = false;
// set interrupt under service flag
port.m_ius = true;
check_interrupts();
return port.m_vector;
}
}
//logerror("z80pio_irq_ack: failed to find an interrupt to ack!\n");
return 0;
}
//-------------------------------------------------
// z80daisy_irq_reti - clear the interrupt
// pending state to allow other interrupts through
//-------------------------------------------------
void z80pio_device::z80daisy_irq_reti()
{
for (int index = PORT_A; index < PORT_COUNT; index++)
{
pio_port &port = m_port[index];
if (port.m_ius)
{
if (LOG) logerror("Z80PIO Port %c Return from Interrupt\n", 'A' + index);
// clear interrupt under service flag
port.m_ius = false;
check_interrupts();
return;
}
}
//logerror("z80pio_irq_reti: failed to find an interrupt to clear IEO on!\n");
}
//**************************************************************************
// READ/WRITE HANDLERS
//**************************************************************************
//-------------------------------------------------
// read - register read
//-------------------------------------------------
READ8_MEMBER( z80pio_device::read )
{
int index = BIT(offset, 0);
return BIT(offset, 1) ? control_read() : data_read(index);
}
//-------------------------------------------------
// write - register write
//-------------------------------------------------
WRITE8_MEMBER( z80pio_device::write )
{
int index = BIT(offset, 0);
BIT(offset, 1) ? control_write(index, data) : data_write(index, data);
}
//-------------------------------------------------
// read_alt - register read
//-------------------------------------------------
READ8_MEMBER( z80pio_device::read_alt )
{
int index = BIT(offset, 1);
return BIT(offset, 0) ? control_read() : data_read(index);
}
//-------------------------------------------------
// write_alt - register write
//-------------------------------------------------
WRITE8_MEMBER( z80pio_device::write_alt )
{
int index = BIT(offset, 1);
BIT(offset, 0) ? control_write(index, data) : data_write(index, data);
}
//**************************************************************************
// DEVICE-LEVEL IMPLEMENTATION
//**************************************************************************
//-------------------------------------------------
// control_read - control register read
//-------------------------------------------------
uint8_t z80pio_device::control_read()
{
return (m_port[PORT_A].m_icw & 0xc0) | (m_port[PORT_B].m_icw >> 4);
}
//-------------------------------------------------
// check_interrupts - update the interrupt state
// over all ports
//-------------------------------------------------
void z80pio_device::check_interrupts()
{
int state = CLEAR_LINE;
bool ius = (m_port[PORT_A].m_ius || m_port[PORT_B].m_ius);
for (int index = PORT_A; index < PORT_COUNT; index++)
{
if (LOG) logerror("Z80PIO Port %c IE %s IP %s IUS %s\n", 'A' + index, m_port[index].m_ie ? "1":"0", m_port[index].m_ip ? "1":"0", m_port[index].m_ius ? "1":"0");
if (!ius && m_port[index].m_ie && m_port[index].m_ip)
{
state = ASSERT_LINE;
}
}
if (LOG) logerror("Z80PIO INT %u\n", state);
m_out_int_cb(state);
}
//**************************************************************************
// PORT-LEVEL IMPLEMENTATION
//**************************************************************************
//-------------------------------------------------
// pio_port - constructor
//-------------------------------------------------
z80pio_device::pio_port::pio_port() :
m_device(nullptr),
m_index(0),
m_mode(0),
m_next_control_word(0),
m_input(0),
m_output(0),
m_ior(0),
m_rdy(false),
m_stb(false),
m_ie(false),
m_ip(false),
m_ius(false),
m_icw(0),
m_vector(0),
m_mask(0),
m_match(false)
{
}
//-------------------------------------------------
// start - set up a port during device startup
//-------------------------------------------------
void z80pio_device::pio_port::start(z80pio_device *device, int index)
{
m_device = device;
m_index = index;
// register for state saving
m_device->save_item(NAME(m_mode), m_index);
m_device->save_item(NAME(m_next_control_word), m_index);
m_device->save_item(NAME(m_input), m_index);
m_device->save_item(NAME(m_output), m_index);
m_device->save_item(NAME(m_ior), m_index);
m_device->save_item(NAME(m_rdy), m_index);
m_device->save_item(NAME(m_stb), m_index);
m_device->save_item(NAME(m_ie), m_index);
m_device->save_item(NAME(m_ip), m_index);
m_device->save_item(NAME(m_ius), m_index);
m_device->save_item(NAME(m_icw), m_index);
m_device->save_item(NAME(m_vector), m_index);
m_device->save_item(NAME(m_mask), m_index);
m_device->save_item(NAME(m_match), m_index);
}
//-------------------------------------------------
// reset - reset a port during device reset
//-------------------------------------------------
void z80pio_device::pio_port::reset()
{
// set mode 1
set_mode(MODE_INPUT);
// reset interrupt enable flip-flops
m_icw &= ~ICW_ENABLE_INT;
m_ie = false;
m_ip = false;
m_ius = false;
m_match = false;
// reset all bits of the data I/O register
m_ior = 0;
// set all bits of the mask control register
m_mask = 0xff;
// reset output register
m_output = 0;
// clear ready line
set_rdy(false);
}
//-------------------------------------------------
// trigger_interrupt - trigger an interrupt from
// this port
//-------------------------------------------------
void z80pio_device::pio_port::trigger_interrupt()
{
m_ip = true;
if (LOG) m_device->logerror("Z80PIO Port %c Transfer Mode Interrupt Pending\n", 'A' + m_index);
check_interrupts();
}
//-------------------------------------------------
// set_rdy - set the port's RDY line
//-------------------------------------------------
void z80pio_device::pio_port::set_rdy(bool state)
{
if (m_rdy == state) return;
if (LOG) m_device->logerror("Z80PIO Port %c Ready: %u\n", 'A' + m_index, state);
m_rdy = state;
if (m_index == PORT_A)
m_device->m_out_ardy_cb(state);
else
m_device->m_out_brdy_cb(state);
}
//-------------------------------------------------
// set_mode - set the port's mode
//-------------------------------------------------
void z80pio_device::pio_port::set_mode(int mode)
{
switch (mode)
{
case MODE_OUTPUT:
if (LOG) m_device->logerror("Z80PIO Port %c Mode: Output\n", 'A' + m_index);
// enable data output
if (m_index == PORT_A)
m_device->m_out_pa_cb((offs_t)0, m_output);
else
m_device->m_out_pb_cb((offs_t)0, m_output);
// assert ready line
set_rdy(true);
// set mode register
m_mode = mode;
break;
case MODE_INPUT:
if (LOG) m_device->logerror("Z80PIO Port %c Mode: Input\n", 'A' + m_index);
// set mode register
m_mode = mode;
break;
case MODE_BIDIRECTIONAL:
if (m_index == PORT_B)
{
m_device->logerror("Z80PIO Port %c Invalid Mode: %u!\n", 'A' + m_index, mode);
}
else
{
if (LOG) m_device->logerror("Z80PIO Port %c Mode: Bidirectional\n", 'A' + m_index);
// set mode register
m_mode = mode;
}
break;
case MODE_BIT_CONTROL:
if (LOG) m_device->logerror("Z80PIO Port %c Mode: Bit Control\n", 'A' + m_index);
if ((m_index == PORT_A) || (m_device->m_port[PORT_A].m_mode != MODE_BIDIRECTIONAL))
{
// clear ready line
set_rdy(false);
}
// disable interrupts until IOR is written
m_ie = false;
check_interrupts();
// set logic equation to false
m_match = false;
// next word is I/O register
m_next_control_word = IOR;
// set mode register
m_mode = mode;
break;
}
}
//-------------------------------------------------
// strobe - strobe data in/out of the port
//-------------------------------------------------
void z80pio_device::pio_port::strobe(bool state)
{
if (LOG) m_device->logerror("Z80PIO Port %c Strobe: %u\n", 'A' + m_index, state);
if (m_device->m_port[PORT_A].m_mode == MODE_BIDIRECTIONAL)
{
if (m_rdy) // port ready
{
if (m_stb && !state) // falling edge
{
if (m_index == PORT_A)
m_device->m_out_pa_cb((offs_t)0, m_output);
else
m_device->m_port[PORT_A].m_input = m_device->m_in_pa_cb(0);
}
else if (!m_stb && state) // rising edge
{
trigger_interrupt();
// clear ready line
set_rdy(false);
}
}
}
else
{
switch (m_mode)
{
case MODE_OUTPUT:
if (m_rdy)
{
if (!m_stb && state) // rising edge
{
trigger_interrupt();
// clear ready line
set_rdy(false);
}
}
break;
case MODE_INPUT:
if (!state)
{
// input port data
if (m_index == PORT_A)
m_input = m_device->m_in_pa_cb(0);
else
m_input = m_device->m_in_pb_cb(0);
}
else if (!m_stb && state) // rising edge
{
trigger_interrupt();
// clear ready line
set_rdy(false);
}
break;
}
}
m_stb = state;
}
//-------------------------------------------------
// read - port I/O read
//-------------------------------------------------
uint8_t z80pio_device::pio_port::read()
{
uint8_t data = 0xff;
switch (m_mode)
{
case MODE_OUTPUT:
data = m_output;
break;
case MODE_BIDIRECTIONAL:
if (m_index == PORT_A)
data = m_output;
break;
case MODE_BIT_CONTROL:
data = m_ior | (m_output & (m_ior ^ 0xff));
break;
}
return data;
}
//-------------------------------------------------
// write - port I/O write
//-------------------------------------------------
void z80pio_device::pio_port::write(uint8_t data)
{
if (m_mode == MODE_BIT_CONTROL)
{
// latch data
m_input = data;
// fetch input data (ignore output lines)
uint8_t data = (m_input & m_ior) | (m_output & ~m_ior);
uint8_t mask = ~m_mask;
bool match = false;
data &= mask;
if ((m_icw & 0x60) == 0 && data != mask) match = true;
else if ((m_icw & 0x60) == 0x20 && data != 0) match = true;
else if ((m_icw & 0x60) == 0x40 && data == 0) match = true;
else if ((m_icw & 0x60) == 0x60 && data == mask) match = true;
if (!m_match && match && !m_ius)
{
// trigger interrupt
m_ip = true;
if (LOG) m_device->logerror("Z80PIO Port %c Bit Control Mode Interrupt Pending\n", 'A' + m_index);
}
m_match = match;
check_interrupts();
}
}
//-------------------------------------------------
// control_write - control register write
//-------------------------------------------------
void z80pio_device::pio_port::control_write(uint8_t data)
{
switch (m_next_control_word)
{
case ANY:
if (!BIT(data, 0))
{
// load interrupt vector
m_vector = data;
if (LOG) m_device->logerror("Z80PIO Port %c Interrupt Vector: %02x\n", 'A' + m_index, data);
// set interrupt enable
m_icw |= ICW_ENABLE_INT;
m_ie = true;
check_interrupts();
}
else
{
switch (data & 0x0f)
{
case 0x0f: // select operating mode
set_mode(data >> 6);
break;
case 0x07: // set interrupt control word
m_icw = data;
if (LOG)
{
m_device->logerror("Z80PIO Port %c Interrupt Enable: %u\n", 'A' + m_index, BIT(data, 7));
m_device->logerror("Z80PIO Port %c Logic: %s\n", 'A' + m_index, BIT(data, 6) ? "AND" : "OR");
m_device->logerror("Z80PIO Port %c Active %s\n", 'A' + m_index, BIT(data, 5) ? "High" : "Low");
m_device->logerror("Z80PIO Port %c Mask Follows: %u\n", 'A' + m_index, BIT(data, 4));
}
if (m_icw & ICW_MASK_FOLLOWS)
{
// disable interrupts until mask is written
m_ie = false;
// reset pending interrupts
m_ip = false;
check_interrupts();
// set logic equation to false
m_match = false;
// next word is mask control
m_next_control_word = MASK;
}
else
{
// set interrupt enable
m_ie = BIT(m_icw, 7) ? true : false;
check_interrupts();
}
break;
case 0x03: // set interrupt enable flip-flop
m_icw = (data & 0x80) | (m_icw & 0x7f);
if (LOG) m_device->logerror("Z80PIO Port %c Interrupt Enable: %u\n", 'A' + m_index, BIT(data, 7));
// set interrupt enable
m_ie = BIT(m_icw, 7) ? true : false;
check_interrupts();
break;
default:
m_device->logerror("Z80PIO Port %c Invalid Control Word: %02x!\n", 'A' + m_index, data);
}
}
break;
case IOR: // data direction register
m_ior = data;
if (LOG) m_device->logerror("Z80PIO Port %c IOR: %02x\n", 'A' + m_index, data);
// set interrupt enable
m_ie = BIT(m_icw, 7) ? true : false;
check_interrupts();
// next word is any
m_next_control_word = ANY;
break;
case MASK: // interrupt mask
m_mask = data;
if (LOG) m_device->logerror("Z80PIO Port %c Mask: %02x\n", 'A' + m_index, data);
// set interrupt enable
m_ie = BIT(m_icw, 7) ? true : false;
check_interrupts();
// next word is any
m_next_control_word = ANY;
break;
}
}
//-------------------------------------------------
// data_read - data register read
//-------------------------------------------------
uint8_t z80pio_device::pio_port::data_read()
{
uint8_t data = 0;
switch (m_mode)
{
case MODE_OUTPUT:
data = m_output;
break;
case MODE_INPUT:
if (!m_stb)
{
// input port data
if (m_index == PORT_A)
m_input = m_device->m_in_pa_cb(0);
else
m_input = m_device->m_in_pb_cb(0);
if (LOG) m_device->logerror("Z80PIO Port %c In: %02x\n", 'A' + m_index, m_input);
}
data = m_input;
// clear ready line
set_rdy(false);
// assert ready line
set_rdy(true);
break;
case MODE_BIDIRECTIONAL:
data = m_input;
// clear ready line
m_device->m_port[PORT_B].set_rdy(false);
// assert ready line
m_device->m_port[PORT_B].set_rdy(true);
break;
case MODE_BIT_CONTROL:
// input port data
if (m_index == PORT_A)
m_input = m_device->m_in_pa_cb(0);
else
m_input = m_device->m_in_pb_cb(0);
if (LOG) m_device->logerror("Z80PIO Port %c In: %02x & %02x\n", 'A' + m_index, m_input, m_ior);
data = (m_input & m_ior) | (m_output & (m_ior ^ 0xff));
break;
}
return data;
}
//-------------------------------------------------
// data_write - data register write
//-------------------------------------------------
void z80pio_device::pio_port::data_write(uint8_t data)
{
switch (m_mode)
{
case MODE_OUTPUT:
// clear ready line
set_rdy(false);
// latch output data
m_output = data;
if (LOG) m_device->logerror("Z80PIO Port %c Out: %02x\n", 'A' + m_index, m_output);
// output data to port
if (m_index == PORT_A)
m_device->m_out_pa_cb((offs_t)0, m_output);
else
m_device->m_out_pb_cb((offs_t)0, m_output);
// assert ready line
set_rdy(true);
break;
case MODE_INPUT:
// latch output data
m_output = data;
break;
case MODE_BIDIRECTIONAL:
// clear ready line
set_rdy(false);
// latch output data
m_output = data;
if (!m_stb)
{
if (LOG) m_device->logerror("Z80PIO Port %c Out: %02x\n", 'A' + m_index, m_output);
// output data to port
if (m_index == PORT_A)
m_device->m_out_pa_cb((offs_t)0, data);
else
m_device->m_out_pb_cb((offs_t)0, data);
}
// assert ready line
set_rdy(true);
break;
case MODE_BIT_CONTROL:
// latch output data
m_output = data;
if (LOG) m_device->logerror("Z80PIO Port %c Out: %02x | %02x\n", 'A' + m_index, m_output, m_ior);
// output data to port
if (m_index == PORT_A)
m_device->m_out_pa_cb((offs_t)0, m_ior | (m_output & (m_ior ^ 0xff)));
else
m_device->m_out_pb_cb((offs_t)0, m_ior | (m_output & (m_ior ^ 0xff)));
break;
}
}