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-rw-r--r--src/devices/bus/nes_ctrl/turbofile.cpp140
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diff --git a/src/devices/bus/nes_ctrl/turbofile.cpp b/src/devices/bus/nes_ctrl/turbofile.cpp
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+++ b/src/devices/bus/nes_ctrl/turbofile.cpp
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+// license:BSD-3-Clause
+// copyright-holders:kmg
+/**********************************************************************
+
+ Nintendo Family Computer ASCII Turbofile SRAM external storage device
+
+ The original 8K Turbofile, emulated here, has been seen with serials
+ AS-TF02 through AS-TF04, differences unknown. We do not support the
+ Turbo File II (yet?), but it appears to simply be a 32K version with
+ a manual switch to select between four 8K banks. Both devices also
+ sport a write protect switch.
+
+**********************************************************************/
+
+#include "emu.h"
+#include "turbofile.h"
+
+//**************************************************************************
+// DEVICE DEFINITIONS
+//**************************************************************************
+
+DEFINE_DEVICE_TYPE(NES_TURBOFILE, nes_turbofile_device, "nes_turbofile", "ASCII Turbofile Backup RAM")
+
+
+INPUT_CHANGED_MEMBER( nes_turbofile_device::lock_changed )
+{
+ m_locked = newval;
+ popmessage("Turbofile Protect Switch %s\n", m_locked ? "ON" : "OFF");
+}
+
+
+static INPUT_PORTS_START( nes_turbofile )
+ PORT_START("LOCK")
+ PORT_BIT( 0x01, IP_ACTIVE_HIGH, IPT_BUTTON1 ) PORT_NAME("Protect Switch") PORT_TOGGLE PORT_CHANGED_MEMBER(DEVICE_SELF, FUNC(nes_turbofile_device::lock_changed), 0)
+INPUT_PORTS_END
+
+//-------------------------------------------------
+// input_ports - device-specific input ports
+//-------------------------------------------------
+
+ioport_constructor nes_turbofile_device::device_input_ports() const
+{
+ return INPUT_PORTS_NAME( nes_turbofile );
+}
+
+
+//-------------------------------------------------
+// device_add_mconfig - add device configuration
+//-------------------------------------------------
+
+void nes_turbofile_device::device_add_mconfig(machine_config &config)
+{
+ NVRAM(config, "nvram", nvram_device::DEFAULT_NONE);
+}
+
+
+//**************************************************************************
+// LIVE DEVICE
+//**************************************************************************
+
+//-------------------------------------------------
+// nes_turbofile_device - constructor
+//-------------------------------------------------
+
+nes_turbofile_device::nes_turbofile_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock)
+ : device_t(mconfig, NES_TURBOFILE, tag, owner, clock)
+ , device_nes_control_port_interface(mconfig, *this)
+ , m_nvram(*this, "nvram")
+ , m_lock(*this, "LOCK")
+ , m_addr(0)
+ , m_bit(0)
+ , m_latch(0)
+ , m_locked(0)
+{
+}
+
+
+//-------------------------------------------------
+// device_start
+//-------------------------------------------------
+
+void nes_turbofile_device::device_start()
+{
+ // 8K RAM
+ m_ram = std::make_unique<u8[]>(0x2000);
+ m_nvram->set_base(m_ram.get(), 0x2000);
+
+ save_pointer(NAME(m_ram), 0x2000);
+ save_item(NAME(m_addr));
+ save_item(NAME(m_bit));
+ save_item(NAME(m_latch));
+ save_item(NAME(m_locked));
+}
+
+
+//-------------------------------------------------
+// device_reset
+//-------------------------------------------------
+
+void nes_turbofile_device::device_reset()
+{
+ m_locked = m_lock->read();
+}
+
+
+//-------------------------------------------------
+// read
+//-------------------------------------------------
+
+u8 nes_turbofile_device::read_exp(offs_t offset)
+{
+ return (offset == 1) ? BIT(m_ram[m_addr], m_bit) << 2 : 0;
+}
+
+//-------------------------------------------------
+// write
+//-------------------------------------------------
+
+void nes_turbofile_device::write(u8 data)
+{
+ if (!BIT(data, 1)) // reset position to start of RAM
+ {
+ m_addr = 0;
+ m_bit = 0;
+ }
+
+ if (!BIT(data, 2) && BIT(m_latch, 2))
+ {
+ if (!m_locked)
+ {
+ m_ram[m_addr] &= ~(1 << m_bit);
+ m_ram[m_addr] |= (data & 1) << m_bit;
+ }
+ m_bit = (m_bit + 1) & 0x07;
+ if (!m_bit)
+ m_addr = (m_addr + 1) & 0x1fff;
+ }
+
+ m_latch = data;
+}