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// license:BSD-3-Clause
// copyright-holders:Curt Coder
/**********************************************************************
Intel 8212 8-Bit Input/Output Port emulation
**********************************************************************/
#include "emu.h"
#include "i8212.h"
//**************************************************************************
// MACROS / CONSTANTS
//**************************************************************************
#define LOG 0
//**************************************************************************
// LIVE DEVICE
//**************************************************************************
// device type definition
const device_type I8212 = &device_creator<i8212_device>;
//-------------------------------------------------
// i8212_device - constructor
//-------------------------------------------------
i8212_device::i8212_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock) :
device_t(mconfig, I8212, "I8212", tag, owner, clock, "i8212", __FILE__),
m_write_irq(*this),
m_read_di(*this),
m_write_do(*this),
m_md(I8212_MODE_INPUT),
m_stb(0)
{
}
//-------------------------------------------------
// device_start - device-specific startup
//-------------------------------------------------
void i8212_device::device_start()
{
// resolve callbacks
m_write_irq.resolve_safe();
m_read_di.resolve_safe(0);
m_write_do.resolve_safe();
// register for state saving
save_item(NAME(m_md));
save_item(NAME(m_stb));
save_item(NAME(m_data));
}
//-------------------------------------------------
// device_reset - device-specific reset
//-------------------------------------------------
void i8212_device::device_reset()
{
m_data = 0;
if (m_md == I8212_MODE_OUTPUT)
{
// output data
m_write_do((offs_t)0, m_data);
}
}
//-------------------------------------------------
// read - data latch read
//-------------------------------------------------
READ8_MEMBER( i8212_device::read )
{
// clear interrupt line
m_write_irq(CLEAR_LINE);
if (LOG) logerror("I8212 '%s' INT: %u\n", tag(), CLEAR_LINE);
return m_data;
}
//-------------------------------------------------
// write - data latch write
//-------------------------------------------------
WRITE8_MEMBER( i8212_device::write )
{
// latch data
m_data = data;
// output data
m_write_do((offs_t)0, m_data);
}
//-------------------------------------------------
// md_w - mode write
//-------------------------------------------------
WRITE_LINE_MEMBER( i8212_device::md_w )
{
if (LOG) logerror("I8212 '%s' Mode: %s\n", tag(), state ? "output" : "input");
m_md = state;
}
//-------------------------------------------------
// stb_w - data strobe write
//-------------------------------------------------
WRITE_LINE_MEMBER( i8212_device::stb_w )
{
if (LOG) logerror("I8212 '%s' STB: %u\n", tag(), state);
if (m_md == I8212_MODE_INPUT)
{
if (m_stb && !state)
{
// input data
m_data = m_read_di(0);
// assert interrupt line
m_write_irq(ASSERT_LINE);
if (LOG) logerror("I8212 '%s' INT: %u\n", tag(), ASSERT_LINE);
}
}
m_stb = state;
}
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