/
msc.cpp
104 lines (79 loc) · 2.66 KB
/
msc.cpp
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// license:BSD-3-Clause
// copyright-holders:Nigel Barnes
/***************************************************************************
Master Smart Cartridge emulation
***************************************************************************/
#include "emu.h"
#include "msc.h"
//**************************************************************************
// DEVICE DEFINITIONS
//**************************************************************************
DEFINE_DEVICE_TYPE(BBC_MSC, bbc_msc_device, "bbc_msc", "Master Smart Cartridge")
//-------------------------------------------------
// INPUT_PORTS( msc )
//-------------------------------------------------
INPUT_PORTS_START(msc)
PORT_START("BUTTON")
PORT_BIT(0x01, IP_ACTIVE_LOW, IPT_BUTTON1) PORT_NAME("Activate") PORT_CODE(KEYCODE_HOME) PORT_CHANGED_MEMBER(DEVICE_SELF, bbc_msc_device, activate, 0)
INPUT_PORTS_END
//-------------------------------------------------
// input_ports - device-specific input ports
//-------------------------------------------------
ioport_constructor bbc_msc_device::device_input_ports() const
{
return INPUT_PORTS_NAME(msc);
}
//**************************************************************************
// LIVE DEVICE
//**************************************************************************
//-------------------------------------------------
// bbc_msc_device - constructor
//-------------------------------------------------
bbc_msc_device::bbc_msc_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
: device_t(mconfig, BBC_MSC, tag, owner, clock)
, device_bbc_cart_interface(mconfig, *this)
, m_button(*this, "BUTTON")
{
}
//-------------------------------------------------
// device_start - device-specific startup
//-------------------------------------------------
void bbc_msc_device::device_start()
{
}
//-------------------------------------------------
// read - cartridge data read
//-------------------------------------------------
uint8_t bbc_msc_device::read(offs_t offset, int infc, int infd, int romqa, int oe, int oe2)
{
uint8_t data = 0xff;
if (oe & !romqa)
{
if (offset & 0x2000)
{
data = m_ram[offset & 0x7ff];
}
else
{
data = m_rom[(offset & 0x1fff) | (m_button->read() << 13)];
}
}
return data;
}
//-------------------------------------------------
// write - cartridge data write
//-------------------------------------------------
void bbc_msc_device::write(offs_t offset, uint8_t data, int infc, int infd, int romqa, int oe, int oe2)
{
if (oe & !romqa)
{
if (offset & 0x2000)
{
m_ram[offset & 0x7ff] = data;
}
}
}
INPUT_CHANGED_MEMBER(bbc_msc_device::activate)
{
m_slot->irq_w(!newval);
}