gen_latch: Allow device to be configured for acknowledgement to occur separately from data reads; use this for batrider (nw)

src/devices/machine/gen_latch.cpp

@@ -28,6 +28,7 @@ DEFINE_DEVICE_TYPE(GENERIC_LATCH_16, generic_latch_16_device, "generic_latch_16"
 
 generic_latch_base_device::generic_latch_base_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, u32 clock) :
 	device_t(mconfig, type, tag, owner, clock),
+	m_separate_acknowledge(false),
 	m_latch_written(false),
 	m_data_pending_cb(*this)
 {
@@ -88,7 +89,8 @@ generic_latch_8_device::generic_latch_8_device(const machine_config &mconfig, co
 
 READ8_MEMBER( generic_latch_8_device::read )
 {
-	set_latch_written(false);
+	if (!has_separate_acknowledge())
+		set_latch_written(false);
 	return m_latched_value;
 }
 
@@ -117,6 +119,17 @@ WRITE_LINE_MEMBER( generic_latch_8_device::clear_w )
 	m_latched_value = 0x00;
 }
 
+READ8_MEMBER( generic_latch_8_device::acknowledge_r )
+{
+	set_latch_written(false);
+	return space.unmap();
+}
+
+WRITE8_MEMBER( generic_latch_8_device::acknowledge_w )
+{
+	set_latch_written(false);
+}
+
 //-------------------------------------------------
 //  soundlatch_sync_callback - time-delayed
 //  callback to set a latch value
@@ -158,7 +171,8 @@ generic_latch_16_device::generic_latch_16_device(const machine_config &mconfig,
 
 READ16_MEMBER( generic_latch_16_device::read )
 {
-	set_latch_written(false);
+	if (!has_separate_acknowledge())
+		set_latch_written(false);
 	return m_latched_value;
 }
 

src/devices/machine/gen_latch.h

@@ -34,6 +34,9 @@ DECLARE_DEVICE_TYPE(GENERIC_LATCH_16, generic_latch_16_device)
 #define MCFG_GENERIC_LATCH_DATA_PENDING_CB(_devcb) \
 	devcb = &generic_latch_base_device::set_data_pending_callback(*device, DEVCB_##_devcb);
 
+#define MCFG_GENERIC_LATCH_SEPARATE_ACKNOWLEDGE(_ack) \
+	generic_latch_base_device::set_separate_acknowledge(*device, _ack);
+
 
 //**************************************************************************
 //  TYPE DEFINITIONS
@@ -51,6 +54,7 @@ public:
 	// static configuration
 	template <class Object> static devcb_base &set_data_pending_callback(device_t &device, Object &&cb)
 	{ return downcast<generic_latch_base_device &>(device).m_data_pending_cb.set_callback(std::forward<Object>(cb)); }
+	static void set_separate_acknowledge(device_t &device, bool ack) { downcast<generic_latch_base_device &>(device).m_separate_acknowledge = ack; }
 
 	DECLARE_READ_LINE_MEMBER(pending_r);
 
@@ -58,10 +62,12 @@ protected:
 	virtual void device_start() override;
 	virtual void device_reset() override;
 
+	bool has_separate_acknowledge() const { return m_separate_acknowledge; }
 	bool is_latch_written() const { return m_latch_written; }
 	void set_latch_written(bool latch_written);
 
 private:
+	bool                    m_separate_acknowledge;
 	bool                    m_latch_written;
 	devcb_write_line        m_data_pending_cb;
 };
@@ -83,6 +89,9 @@ public:
 	DECLARE_WRITE_LINE_MEMBER( preset_w );
 	DECLARE_WRITE_LINE_MEMBER( clear_w );
 
+	DECLARE_READ8_MEMBER( acknowledge_r );
+	DECLARE_WRITE8_MEMBER( acknowledge_w );
+
 	void preset_w(u8 value) { m_latched_value = value; }
 
 protected:

src/mame/drivers/toaplan2.cpp

@@ -850,30 +850,11 @@ WRITE8_MEMBER(toaplan2_state::raizing_oki_bankswitch_w)
 }
 
 
-WRITE16_MEMBER(toaplan2_state::bgaregga_soundlatch_w)
-{
-	if (ACCESSING_BITS_0_7)
-	{
-		m_soundlatch->write(space, offset, data & 0xff);
-		m_audiocpu->set_input_line(0, HOLD_LINE);
-	}
-}
-
-
 READ8_MEMBER(toaplan2_state::bgaregga_E01D_r)
 {
 	// the Z80 reads this address during its IRQ routine,
 	// and reads the soundlatch only if the lowest bit is clear.
-	return 0;
+	return m_soundlatch->pending_r() ? 0 : 1;
-}
-
-
-WRITE8_MEMBER(toaplan2_state::bgaregga_E00C_w)
-{
-	// the Z80 writes here after reading the soundlatch.
-	// I would think that this was an acknowledge latch like
-	// batrider and bbakraid have, except that on the 68000 side
-	// there's no corresponding read...
 }
 
 
@@ -1371,7 +1352,7 @@ static ADDRESS_MAP_START( bgaregga_68k_mem, AS_PROGRAM, 16, toaplan2_state )
 	AM_RANGE(0x502000, 0x502fff) AM_RAM AM_SHARE("tx_lineselect")
 	AM_RANGE(0x503000, 0x5031ff) AM_RAM_WRITE(toaplan2_tx_linescroll_w) AM_SHARE("tx_linescroll")
 	AM_RANGE(0x503200, 0x503fff) AM_RAM
-	AM_RANGE(0x600000, 0x600001) AM_WRITE(bgaregga_soundlatch_w)
+	AM_RANGE(0x600000, 0x600001) AM_DEVWRITE8("soundlatch", generic_latch_8_device, write, 0x00ff)
 ADDRESS_MAP_END
 
 
@@ -1460,7 +1441,7 @@ static ADDRESS_MAP_START( bgaregga_sound_z80_mem, AS_PROGRAM, 8, toaplan2_state
 	AM_RANGE(0xe004, 0xe004) AM_DEVREADWRITE("oki", okim6295_device, read, write)
 	AM_RANGE(0xe006, 0xe008) AM_WRITE(raizing_oki_bankswitch_w)
 	AM_RANGE(0xe00a, 0xe00a) AM_WRITE(raizing_z80_bankswitch_w)
-	AM_RANGE(0xe00c, 0xe00c) AM_WRITE(bgaregga_E00C_w)
+	AM_RANGE(0xe00c, 0xe00c) AM_DEVWRITE("soundlatch", generic_latch_8_device, acknowledge_w)
 	AM_RANGE(0xe01c, 0xe01c) AM_DEVREAD("soundlatch", generic_latch_8_device, read)
 	AM_RANGE(0xe01d, 0xe01d) AM_READ(bgaregga_E01D_r)
 ADDRESS_MAP_END
@@ -4176,6 +4157,8 @@ static MACHINE_CONFIG_START( bgaregga )
 	MCFG_SPEAKER_STANDARD_MONO("mono")
 
 	MCFG_GENERIC_LATCH_8_ADD("soundlatch")
+	MCFG_GENERIC_LATCH_DATA_PENDING_CB(INPUTLINE("audiocpu", 0))
+	MCFG_GENERIC_LATCH_SEPARATE_ACKNOWLEDGE(true)
 
 	MCFG_YM2151_ADD("ymsnd", XTAL_32MHz/8)
 	MCFG_SOUND_ROUTE(ALL_OUTPUTS, "mono", 1.0)

src/mame/includes/toaplan2.h

@@ -102,9 +102,7 @@ public:
 	DECLARE_READ8_MEMBER(fixeight_region_r);
 	DECLARE_WRITE8_MEMBER(raizing_z80_bankswitch_w);
 	DECLARE_WRITE8_MEMBER(raizing_oki_bankswitch_w);
-	DECLARE_WRITE16_MEMBER(bgaregga_soundlatch_w);
 	DECLARE_READ8_MEMBER(bgaregga_E01D_r);
-	DECLARE_WRITE8_MEMBER(bgaregga_E00C_w);
 	DECLARE_READ16_MEMBER(batrider_z80_busack_r);
 	DECLARE_WRITE16_MEMBER(batrider_z80_busreq_w);
 	DECLARE_READ16_MEMBER(batrider_z80rom_r);