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-rw-r--r--src/devices/bus/c64/vw64.c127
1 files changed, 127 insertions, 0 deletions
diff --git a/src/devices/bus/c64/vw64.c b/src/devices/bus/c64/vw64.c
new file mode 100644
index 00000000000..fdc21ff4a05
--- /dev/null
+++ b/src/devices/bus/c64/vw64.c
@@ -0,0 +1,127 @@
+// license:BSD-3-Clause
+// copyright-holders:Curt Coder
+/**********************************************************************
+
+ VizaWrite 64 cartridge emulation
+
+**********************************************************************/
+
+/*
+
+ PCB Layout
+ ----------
+
+ |===========================|
+ |=| LS10 LS122 C |
+ |=| R |
+ |=| |
+ |=| |
+ |=| ROM0 ROM2 ROM1 |
+ |=| |
+ |=| |
+ |=| |
+ |===========================|
+
+ ROM0 - Mitsubishi M5L2764K 8Kx8 EPROM "U"
+ ROM1 - Mitsubishi M5L2764K 8Kx8 EPROM "3"
+ ROM2 - Mitsubishi M5L2764K 8Kx8 EPROM "2" (located on solder side)
+ R - 56K
+ C - 47uF
+
+*/
+
+#include "vw64.h"
+
+
+
+//**************************************************************************
+// MACROS/CONSTANTS
+//**************************************************************************
+
+#define UNSCRAMBLE_ADDRESS(_offset) \
+ BITSWAP16(_offset,15,14,13,12,6,2,8,10,11,9,7,5,4,3,1,0)
+
+#define UNSCRAMBLE_DATA(_data) \
+ BITSWAP8(_data,7,6,0,5,1,4,2,3)
+
+
+// 74LS122 tW=0.45*R*C = 1.1844s
+#define TIMER_PERIOD 1184
+
+
+
+//**************************************************************************
+// DEVICE DEFINITIONS
+//**************************************************************************
+
+const device_type C64_VW64 = &device_creator<c64_vizawrite_cartridge_device>;
+
+
+
+//**************************************************************************
+// LIVE DEVICE
+//**************************************************************************
+
+//-------------------------------------------------
+// c64_vizawrite_cartridge_device - constructor
+//-------------------------------------------------
+
+c64_vizawrite_cartridge_device::c64_vizawrite_cartridge_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock) :
+ device_t(mconfig, C64_VW64, "VizaWrite 64", tag, owner, clock, "c64_vizawrite", __FILE__),
+ device_c64_expansion_card_interface(mconfig, *this)
+{
+}
+
+
+//-------------------------------------------------
+// device_start - device-specific startup
+//-------------------------------------------------
+
+void c64_vizawrite_cartridge_device::device_start()
+{
+ // allocate timer
+ m_game_timer = timer_alloc();
+}
+
+
+//-------------------------------------------------
+// device_reset - device-specific reset
+//-------------------------------------------------
+
+void c64_vizawrite_cartridge_device::device_reset()
+{
+ m_game = 0;
+
+ m_game_timer->adjust(attotime::from_msec(TIMER_PERIOD), 0);
+}
+
+
+//-------------------------------------------------
+// device_timer - handler timer events
+//-------------------------------------------------
+
+void c64_vizawrite_cartridge_device::device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr)
+{
+ m_game = 1;
+}
+
+
+//-------------------------------------------------
+// c64_cd_r - cartridge data read
+//-------------------------------------------------
+
+UINT8 c64_vizawrite_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)
+ {
+ offs_t addr = (m_game << 13) | (offset & 0x1fff);
+ data = UNSCRAMBLE_DATA(m_roml[UNSCRAMBLE_ADDRESS(addr)]);
+ }
+ else if (!romh)
+ {
+ offs_t addr = offset & 0x1fff;
+ data = UNSCRAMBLE_DATA(m_romh[UNSCRAMBLE_ADDRESS(addr)]);
+ }
+
+ return data;
+}