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Diffstat (limited to 'src/devices/bus/c64/epyx_fast_load.c')
-rw-r--r--src/devices/bus/c64/epyx_fast_load.c116
1 files changed, 116 insertions, 0 deletions
diff --git a/src/devices/bus/c64/epyx_fast_load.c b/src/devices/bus/c64/epyx_fast_load.c
new file mode 100644
index 00000000000..7b0dfeb5934
--- /dev/null
+++ b/src/devices/bus/c64/epyx_fast_load.c
@@ -0,0 +1,116 @@
+// license:BSD-3-Clause
+// copyright-holders:Curt Coder
+/**********************************************************************
+
+ Epyx Fast Load cartridge emulation
+
+**********************************************************************/
+
+#include "epyx_fast_load.h"
+
+
+
+//**************************************************************************
+// MACROS/CONSTANTS
+//**************************************************************************
+
+// t = R*C = 3.3K * 0.47uF * 40% Vtr = 792.2905424610516 usec
+// (3.3K pull-up on the EXROM line inside the C64, PLA Vih min = 2.0V = 40% of 5.0V)
+#define TIMER_PERIOD 792
+
+
+
+//**************************************************************************
+// DEVICE DEFINITIONS
+//**************************************************************************
+
+const device_type C64_EPYX_FAST_LOAD = &device_creator<c64_epyx_fast_load_cartridge_device>;
+
+
+
+//**************************************************************************
+// LIVE DEVICE
+//**************************************************************************
+
+//-------------------------------------------------
+// c64_epyx_fast_load_cartridge_device - constructor
+//-------------------------------------------------
+
+c64_epyx_fast_load_cartridge_device::c64_epyx_fast_load_cartridge_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock) :
+ device_t(mconfig, C64_EPYX_FAST_LOAD, "C64 Epyx Fast Load cartridge", tag, owner, clock, "c64_epyx_fast_load", __FILE__),
+ device_c64_expansion_card_interface(mconfig, *this)
+{
+}
+
+
+//-------------------------------------------------
+// device_start - device-specific startup
+//-------------------------------------------------
+
+void c64_epyx_fast_load_cartridge_device::device_start()
+{
+ // allocate timer
+ m_exrom_timer = timer_alloc();
+}
+
+
+//-------------------------------------------------
+// device_reset - device-specific reset
+//-------------------------------------------------
+
+void c64_epyx_fast_load_cartridge_device::device_reset()
+{
+ m_exrom = 0;
+ m_exrom_timer->adjust(attotime::from_usec(TIMER_PERIOD), 0);
+}
+
+
+//-------------------------------------------------
+// device_timer - handler timer events
+//-------------------------------------------------
+
+void c64_epyx_fast_load_cartridge_device::device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr)
+{
+ m_exrom = 1;
+}
+
+
+//-------------------------------------------------
+// c64_cd_r - cartridge data read
+//-------------------------------------------------
+
+UINT8 c64_epyx_fast_load_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)
+ {
+ m_exrom = 0;
+ m_exrom_timer->adjust(attotime::from_usec(TIMER_PERIOD), 0);
+
+ data = m_roml[offset & 0x1fff];
+ }
+ else if (!io1)
+ {
+ m_exrom = 0;
+ m_exrom_timer->adjust(attotime::from_usec(TIMER_PERIOD), 0);
+ }
+ else if (!io2)
+ {
+ data = m_roml[offset & 0x1fff];
+ }
+
+ return data;
+}
+
+
+//-------------------------------------------------
+// c64_cd_w - cartridge data write
+//-------------------------------------------------
+
+void c64_epyx_fast_load_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)
+ {
+ m_exrom = 0;
+ m_exrom_timer->adjust(attotime::from_usec(TIMER_PERIOD), 0);
+ }
+}