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// license:BSD-3-Clause
// copyright-holders:Nigel Barnes
/***************************************************************************
Advanced Battery-Backed RAM
***************************************************************************/
#include "emu.h"
#include "abr.h"
//**************************************************************************
// DEVICE DEFINITIONS
//**************************************************************************
DEFINE_DEVICE_TYPE(ELECTRON_ABR, electron_abr_device, "electron_abr", "Electron Advanced Battery-Backed RAM cartridge")
//**************************************************************************
// LIVE DEVICE
//**************************************************************************
//-------------------------------------------------
// electron_abr_device - constructor
//-------------------------------------------------
electron_abr_device::electron_abr_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
: device_t(mconfig, ELECTRON_ABR, tag, owner, clock)
, device_electron_cart_interface(mconfig, *this)
{
}
//-------------------------------------------------
// device_start - device-specific startup
//-------------------------------------------------
void electron_abr_device::device_start()
{
m_bank_locked[0] = false;
m_bank_locked[1] = false;
// register for save states
save_item(NAME(m_bank_locked));
}
//-------------------------------------------------
// read - cartridge data read
//-------------------------------------------------
uint8_t electron_abr_device::read(offs_t offset, int infc, int infd, int romqa, int oe, int oe2)
{
uint8_t data = 0xff;
if (oe)
{
data = m_nvram[(offset & 0x3fff) | (romqa << 14)];
}
return data;
}
//-------------------------------------------------
// write - cartridge data write
//-------------------------------------------------
void electron_abr_device::write(offs_t offset, uint8_t data, int infc, int infd, int romqa, int oe, int oe2)
{
if (infc)
{
switch (offset & 0xff)
{
case 0xdc:
m_bank_locked[0] = false;
break;
case 0xdd:
m_bank_locked[0] = true;
break;
case 0xde:
m_bank_locked[1] = false;
break;
case 0xdf:
m_bank_locked[1] = true;
break;
}
}
else if (oe)
{
if (!m_bank_locked[romqa])
{
m_nvram[(offset & 0x3fff) | (romqa << 14)] = data;
}
}
}
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