apple2: //e, //c, and friends now have No-Slot Clock support. [R. Belmont]

ds1315: Added support to emulate DS121x parts where the RTC sits in a
ROM's address space. [R. Belmont]

src/devices/machine/ds1315.cpp

@@ -1,12 +1,16 @@
 // license:BSD-3-Clause
-// copyright-holders:Tim Lindner
+// copyright-holders:Tim Lindner, R. Belmont
 /*****************************************************************************************
 
-    ds1315.c
+    ds1315.cpp
 
     Dallas Semiconductor's Phantom Time Chip DS1315.
     NOTE: writes are decoded, but the host's time will always be returned when asked.
 
+	November 2017: R. Belmont added capability to emulate DS1216 and other DS121x 
+	parts where the clock sits in the same place as a ROM.  The backing callback
+	returns the ROM contents when the RTC is locked.
+
     April 2015: chip enable / chip reset / phantom writes by Karl-Ludwig Deisenhofer
 
     November 2001: implementation by Tim Lindner
@@ -29,7 +33,10 @@
 DEFINE_DEVICE_TYPE(DS1315, ds1315_device, "ds1315", "Dallas DS1315 Phantom Time Chip")
 
 ds1315_device::ds1315_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
-	: device_t(mconfig, DS1315, tag, owner, clock), m_mode(), m_count(0)
+	: device_t(mconfig, DS1315, tag, owner, clock), 
+	m_backing_read(*this),	
+	m_mode(), 
+	m_count(0)
 {
 }
 
@@ -39,6 +46,8 @@ ds1315_device::ds1315_device(const machine_config &mconfig, const char *tag, dev
 
 void ds1315_device::device_start()
 {
+	m_backing_read.resolve_safe(0xff);
+
 	save_item(NAME(m_count));
 	save_item(NAME(m_mode));
 	save_item(NAME(m_raw_data));
@@ -77,6 +86,37 @@ static const uint8_t ds1315_pattern[] =
     IMPLEMENTATION
 ***************************************************************************/
 
+// automated read, does all the work the real Dallas chip does
+READ8_MEMBER( ds1315_device::read )
+{
+	if (m_mode == DS_SEEK_MATCHING)
+	{
+		if (offset & 1)
+		{
+			read_1(space, 0);
+		}
+		else
+		{
+			read_0(space, 0);
+		}
+
+		if (offset & 4)
+		{
+			m_count = 0;
+			m_mode = DS_SEEK_MATCHING;
+		}
+
+		return m_backing_read(offset);		
+	}	
+	else if (m_mode == DS_CALENDAR_IO)
+	{
+		return read_data(space, offset);
+	}
+
+	return 0xff;	// shouldn't happen, but compilers don't know that
+}
+
+
 /*-------------------------------------------------
  read_0 (actual data)
  -------------------------------------------------*/
@@ -92,7 +132,6 @@ READ8_MEMBER( ds1315_device::read_0 )
 			m_mode = DS_CALENDAR_IO;
 			fill_raw_data();
 		}
-
 		return 0;
 	}
 
@@ -246,7 +285,7 @@ void ds1315_device::input_raw_data()
 	raw[6] = bcd_2_dec(raw[6]); // month
 	raw[7] = bcd_2_dec(raw[7]); // year (two digits)
 
-	printf("\nDS1315 RTC INPUT (WILL BE IGNORED) mm/dd/yy  hh:mm:ss - %02d/%02d/%02d %02d/%02d/%02d",
+	logerror("\nDS1315 RTC INPUT (WILL BE IGNORED) mm/dd/yy  hh:mm:ss - %02d/%02d/%02d %02d/%02d/%02d",
 				raw[6], raw[5], raw[7], raw[3], raw[2], raw[1]
 			);
 }

src/devices/machine/ds1315.h

@@ -15,7 +15,15 @@
 
 #pragma once
 
+/***************************************************************************
+    DEVICE CONFIGURATION MACROS
+***************************************************************************/
 
+#define MCFG_DS1315_ADD(_tag) \
+	MCFG_DEVICE_ADD(_tag, DS1315, 0)
+
+#define MCFG_DS1315_BACKING_HANDLER(_devcb) \
+	devcb = &ds1315_device::set_backing_handler(*device, DEVCB_##_devcb);
 
 /***************************************************************************
     MACROS
@@ -27,6 +35,9 @@ public:
 	ds1315_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock);
 	~ds1315_device() {}
 
+	// this handler automates the bits 0/2 stuff
+	DECLARE_READ8_MEMBER(read);
+	
 	DECLARE_READ8_MEMBER(read_0);
 	DECLARE_READ8_MEMBER(read_1);
 	DECLARE_READ8_MEMBER(read_data);
@@ -35,12 +46,17 @@ public:
 	bool chip_enable();
 	void chip_reset();
 
+	template <class Object> static devcb_base &set_backing_handler(device_t &device, Object &&cb)
+	{ return downcast<ds1315_device &>(device).m_backing_read.set_callback(std::forward<Object>(cb)); }
+
 protected:
 	// device-level overrides
 	virtual void device_start() override;
 	virtual void device_reset() override;
 
 private:
+	devcb_read8 m_backing_read;
+	
 	enum mode_t : u8
 	{
 		DS_SEEK_MATCHING,
@@ -61,12 +77,4 @@ ALLOW_SAVE_TYPE(ds1315_device::mode_t);
 
 DECLARE_DEVICE_TYPE(DS1315, ds1315_device)
 
-/***************************************************************************
-    DEVICE CONFIGURATION MACROS
-***************************************************************************/
-
-#define MCFG_DS1315_ADD(_tag) \
-	MCFG_DEVICE_ADD(_tag, DS1315, 0)
-
-
 #endif // MAME_MACHINE_DS1315_H

src/mame/drivers/apple2e.cpp

@@ -113,6 +113,7 @@ Address bus A0-A11 is Y0-Y11
 #include "machine/ram.h"
 #include "machine/sonydriv.h"
 #include "machine/timer.h"
+#include "machine/ds1315.h"
 
 #include "bus/a2bus/a2bus.h"
 #include "bus/a2bus/a2diskii.h"
@@ -241,7 +242,8 @@ public:
 		m_acia1(*this, IIC_ACIA1_TAG),
 		m_acia2(*this, IIC_ACIA2_TAG),
 		m_laserudc(*this, LASER128_UDC_TAG),
-		m_iicpiwm(*this, IICP_IWM_TAG)
+		m_iicpiwm(*this, IICP_IWM_TAG),
+		m_ds1315(*this, "nsc")
 	{ }
 
 	required_device<cpu_device> m_maincpu;
@@ -274,6 +276,7 @@ public:
 	optional_device<mos6551_device> m_acia1, m_acia2;
 	optional_device<applefdc_base_device> m_laserudc;
 	optional_device<iwm_device> m_iicpiwm;
+	required_device<ds1315_device> m_ds1315;
 
 	TIMER_DEVICE_CALLBACK_MEMBER(apple2_interrupt);
 	TIMER_DEVICE_CALLBACK_MEMBER(ay3600_repeat);
@@ -356,6 +359,7 @@ public:
 	DECLARE_WRITE_LINE_MEMBER(ay3600_ako_w);
 	DECLARE_READ8_MEMBER(memexp_r);
 	DECLARE_WRITE8_MEMBER(memexp_w);
+	DECLARE_READ8_MEMBER(nsc_backing_r);
 
 private:
 	int m_speaker_state;
@@ -2171,17 +2175,12 @@ void apple2e_state::write_slot_rom(address_space &space, int slotbias, int offse
 
 uint8_t apple2e_state::read_int_rom(address_space &space, int slotbias, int offset)
 {
-#if 0
+	//return m_rom_ptr[slotbias + offset];
-	if ((m_cnxx_slot == CNXX_UNCLAIMED) && (!machine().side_effect_disabled()))
+	return m_ds1315->read(space, slotbias + offset);
-	{
-		m_cnxx_slot = CNXX_INTROM;
-		update_slotrom_banks();
-	}
-#endif
-
-	return m_rom_ptr[slotbias + offset];
 }
 
+READ8_MEMBER(apple2e_state::nsc_backing_r) { return m_rom_ptr[offset]; }
+
 READ8_MEMBER(apple2e_state::c100_r)  { return read_slot_rom(space, 1, offset); }
 READ8_MEMBER(apple2e_state::c100_int_r)  { return read_int_rom(space, 0x100, offset); }
 READ8_MEMBER(apple2e_state::c100_int_bank_r)  { return read_int_rom(space, 0x4100, offset); }
@@ -3856,6 +3855,10 @@ static MACHINE_CONFIG_START( apple2e )
 	MCFG_SOUND_ADD(A2_SPEAKER_TAG, SPEAKER_SOUND, 0)
 	MCFG_SOUND_ROUTE(ALL_OUTPUTS, "mono", 1.00)
 
+	/* DS1315 for no-slot clock */
+	MCFG_DS1315_ADD("nsc")
+	MCFG_DS1315_BACKING_HANDLER(READ8(apple2e_state, nsc_backing_r))
+
 	/* RAM */
 	MCFG_RAM_ADD(RAM_TAG)
 	MCFG_RAM_DEFAULT_SIZE("64K")