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Diffstat (limited to 'src/devices/machine/ds128x.cpp')
-rw-r--r--src/devices/machine/ds128x.cpp58
1 files changed, 57 insertions, 1 deletions
diff --git a/src/devices/machine/ds128x.cpp b/src/devices/machine/ds128x.cpp
index 7a397aab303..91e022e07e7 100644
--- a/src/devices/machine/ds128x.cpp
+++ b/src/devices/machine/ds128x.cpp
@@ -10,7 +10,12 @@ DEFINE_DEVICE_TYPE(DS12885, ds12885_device, "ds12885", "DS12885 RTC/NVRAM")
//-------------------------------------------------
ds12885_device::ds12885_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
- : mc146818_device(mconfig, DS12885, tag, owner, clock)
+ : ds12885_device(mconfig, DS12885, tag, owner, clock)
+{
+}
+
+ds12885_device::ds12885_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, uint32_t clock)
+ : mc146818_device(mconfig, type, tag, owner, clock)
{
}
@@ -23,3 +28,54 @@ int ds12885_device::get_timer_bypass()
return 22; // No tick
}
+
+DEFINE_DEVICE_TYPE(DS12885EXT, ds12885ext_device, "ds12885ext", "DS12885 RTC/NVRAM size 256 bytes")
+
+//-------------------------------------------------
+// ds12885ext_device - constructor
+//-------------------------------------------------
+
+ds12885ext_device::ds12885ext_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
+ : ds12885_device(mconfig, DS12885EXT, tag, owner, clock)
+{
+}
+
+//-------------------------------------------------
+// ds12885ext_device - handlers that allow acces to extended memory size
+//-------------------------------------------------
+
+uint8_t ds12885ext_device::read_extended(offs_t offset)
+{
+ switch (offset)
+ {
+ case 0:
+ case 1:
+ return read(offset);
+ break;
+ case 2:
+ case 3:
+ return read(offset - 2);
+ break;
+ default:
+ return 0xff;
+ }
+}
+
+void ds12885ext_device::write_extended(offs_t offset, uint8_t data)
+{
+ switch (offset)
+ {
+ case 0:
+ write(offset, data & 127);
+ break;
+ case 1:
+ write(offset, data);
+ break;
+ case 2:
+ write(offset - 2, data);
+ break;
+ case 3:
+ write(offset - 2, data);
+ break;
+ }
+}