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-rw-r--r--src/devices/bus/c64/stardos.c194
1 files changed, 194 insertions, 0 deletions
diff --git a/src/devices/bus/c64/stardos.c b/src/devices/bus/c64/stardos.c
new file mode 100644
index 00000000000..4c92982c695
--- /dev/null
+++ b/src/devices/bus/c64/stardos.c
@@ -0,0 +1,194 @@
+// license:BSD-3-Clause
+// copyright-holders:Curt Coder
+/**********************************************************************
+
+ StarPoint Software StarDOS cartridge emulation
+
+**********************************************************************/
+
+/*
+
+ PCB Layout
+ ----------
+
+ |===========================|
+ |=| |
+ |=| LS30 |
+ |=| LS157 |
+ |=| LS00 |
+ |=| ROM |
+ |=| 7407 |
+ |=| |
+ |=| SW1|
+ |===========================|
+
+ ROM - Toshiba TMM271128D-25 16Kx8 EPROM
+
+*/
+
+#include "stardos.h"
+
+
+
+//**************************************************************************
+// MACROS/CONSTANTS
+//**************************************************************************
+
+#define IO1_FULL_CHARGE 27
+#define IO2_FULL_CHARGE 42
+
+
+
+//**************************************************************************
+// DEVICE DEFINITIONS
+//**************************************************************************
+
+const device_type C64_STARDOS = &device_creator<c64_stardos_cartridge_device>;
+
+
+//-------------------------------------------------
+// INPUT_PORTS( c64_stardos )
+//-------------------------------------------------
+
+static INPUT_PORTS_START( c64_stardos )
+ PORT_START("RESET")
+ PORT_BIT( 0x01, IP_ACTIVE_LOW, IPT_OTHER ) PORT_NAME("Reset") PORT_CODE(KEYCODE_F11) PORT_WRITE_LINE_DEVICE_MEMBER(DEVICE_SELF_OWNER, c64_expansion_slot_device, reset_w)
+INPUT_PORTS_END
+
+
+//-------------------------------------------------
+// input_ports - device-specific input ports
+//-------------------------------------------------
+
+ioport_constructor c64_stardos_cartridge_device::device_input_ports() const
+{
+ return INPUT_PORTS_NAME( c64_stardos );
+}
+
+
+
+//**************************************************************************
+// INLINE HELPERS
+//**************************************************************************
+
+//-------------------------------------------------
+// charge_io1_capacitor -
+//-------------------------------------------------
+
+inline void c64_stardos_cartridge_device::charge_io1_capacitor()
+{
+ m_io1_charge++;
+
+ if (m_io1_charge >= IO1_FULL_CHARGE)
+ {
+ m_exrom = 0;
+ m_io1_charge = 0;
+ }
+}
+
+
+//-------------------------------------------------
+// charge_io2_capacitor -
+//-------------------------------------------------
+
+void c64_stardos_cartridge_device::charge_io2_capacitor()
+{
+ m_io2_charge++;
+
+ if (m_io2_charge >= IO2_FULL_CHARGE)
+ {
+ m_exrom = 1;
+ m_io2_charge = 0;
+ }
+}
+
+
+
+//**************************************************************************
+// LIVE DEVICE
+//**************************************************************************
+
+//-------------------------------------------------
+// c64_stardos_cartridge_device - constructor
+//-------------------------------------------------
+
+c64_stardos_cartridge_device::c64_stardos_cartridge_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock) :
+ device_t(mconfig, C64_STARDOS, "C64 StarDOS cartridge", tag, owner, clock, "c64_stardos", __FILE__),
+ device_c64_expansion_card_interface(mconfig, *this),
+ m_io1_charge(0),
+ m_io2_charge(0)
+{
+}
+
+
+//-------------------------------------------------
+// device_start - device-specific startup
+//-------------------------------------------------
+
+void c64_stardos_cartridge_device::device_start()
+{
+ // state saving
+ save_item(NAME(m_io1_charge));
+ save_item(NAME(m_io2_charge));
+}
+
+
+//-------------------------------------------------
+// c64_cd_r - cartridge data read
+//-------------------------------------------------
+
+UINT8 c64_stardos_cartridge_device::c64_cd_r(address_space &space, offs_t offset, UINT8 data, int sphi2, int ba, int roml, int romh, int io1, int io2)
+{
+ if (!roml || !romh)
+ {
+ // TODO BITSWAP8(7,6,5,4,3,1,2,0) ?
+ data = m_roml[offset & 0x3fff];
+ }
+ else if (!io1)
+ {
+ charge_io1_capacitor();
+ }
+ else if (!io2)
+ {
+ charge_io2_capacitor();
+ }
+
+ return data;
+}
+
+
+//-------------------------------------------------
+// c64_cd_w - cartridge data write
+//-------------------------------------------------
+
+void c64_stardos_cartridge_device::c64_cd_w(address_space &space, offs_t offset, UINT8 data, int sphi2, int ba, int roml, int romh, int io1, int io2)
+{
+ if (!io1)
+ {
+ charge_io1_capacitor();
+ }
+ else if (!io2)
+ {
+ charge_io2_capacitor();
+ }
+}
+
+
+//-------------------------------------------------
+// c64_game_r - GAME read
+//-------------------------------------------------
+
+int c64_stardos_cartridge_device::c64_game_r(offs_t offset, int sphi2, int ba, int rw)
+{
+ return !(sphi2 && ba & rw & ((offset & 0xe000) == 0xe000) & m_slot->hiram());
+}
+
+
+//-------------------------------------------------
+// c64_exrom_r - EXROM read
+//-------------------------------------------------
+
+int c64_stardos_cartridge_device::c64_exrom_r(offs_t offset, int sphi2, int ba, int rw)
+{
+ return (BIT(offset, 13)) ? 1 : m_exrom;
+}