Merge pull request #1954 from ajrhacker/msm5205_change_clock

MSM5205 architectural cleanups (nw)

src/devices/sound/msm5205.cpp

@@ -28,6 +28,9 @@
 
     Data is streamed from a CPU by means of a clock generated on the chip.
 
+    Holding the rate selector lines (S1 and S2) both high places the MSM5205 in an undocumented
+    mode which disables the sampling clock generator and makes VCK an input line.
+
     A reset signal is set high or low to determine whether playback (and interrupts) are occurring.
 
   MSM6585: is an upgraded MSM5205 voice synth IC.
@@ -38,7 +41,7 @@
 
    Differences between MSM6585 & MSM5205:
 
-                              MSM6586          MSM5205
+                              MSM6585          MSM5205
     Master clock frequency    640kHz           384kHz
     Sampling frequency        4k/8k/16k/32kHz  4k/6k/8kHz
     ADPCM bit length          4-bit            3-bit/4-bit
@@ -46,7 +49,7 @@
     Low-pass filter           -40dB/oct        N/A
     Overflow prevent circuit  Included         N/A
 
-    Timer callback at VCLK low edge on MSM5205 (at rising edge on MSM6585)
+    Data input follows VCK falling edge on MSM5205 (VCK rising edge on MSM6585)
 
    TODO:
    - lowpass filter for MSM6585
@@ -57,39 +60,50 @@ const device_type MSM5205 = &device_creator<msm5205_device>;
 const device_type MSM6585 = &device_creator<msm6585_device>;
 
 
-msm5205_device::msm5205_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
+msm5205_device::msm5205_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock)
 					: device_t(mconfig, MSM5205, "MSM5205", tag, owner, clock, "msm5205", __FILE__),
 						device_sound_interface(mconfig, *this),
-						m_prescaler(0),
+						m_s1(false),
-						m_bitwidth(0),
+						m_s2(false),
-						m_select(0),
+						m_bitwidth(4),
 						m_vclk_cb(*this)
 {
 }
 
-msm5205_device::msm5205_device(const machine_config &mconfig, device_type type, const char *name, const char *tag, device_t *owner, uint32_t clock, const char *shortname, const char *source)
+msm5205_device::msm5205_device(const machine_config &mconfig, device_type type, const char *name, const char *tag, device_t *owner, u32 clock, const char *shortname, const char *source)
 					: device_t(mconfig, type, name, tag, owner, clock, shortname, source),
 						device_sound_interface(mconfig, *this),
-						m_prescaler(0),
+						m_s1(false),
-						m_bitwidth(0),
+						m_s2(false),
-						m_select(0),
+						m_bitwidth(4),
 						m_vclk_cb(*this)
 {
 }
 
 
-msm6585_device::msm6585_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
+msm6585_device::msm6585_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock)
 					: msm5205_device(mconfig, MSM6585, "MSM6585", tag, owner, clock, "msm6585", __FILE__)
 {
 }
 
+//-------------------------------------------------
+//  set_prescaler_selector - configuration helper
+//-------------------------------------------------
+
+void msm5205_device::set_prescaler_selector(device_t &device, int select)
+{
+	msm5205_device &msm = downcast<msm5205_device &>(device);
+	msm.m_s1 = BIT(select, 1);
+	msm.m_s2 = BIT(select, 0);
+	msm.m_bitwidth = (select & 4) ? 4 : 3;
+}
+
 //-------------------------------------------------
 //  device_start - device-specific startup
 //-------------------------------------------------
 
 void msm5205_device::device_start()
 {
-	m_mod_clock = clock();
 	m_vclk_cb.resolve();
 
 	/* compute the difference tables */
@@ -100,11 +114,11 @@ void msm5205_device::device_start()
 	m_timer = machine().scheduler().timer_alloc(timer_expired_delegate(FUNC(msm5205_device::vclk_callback), this));
 
 	/* register for save states */
-	save_item(NAME(m_mod_clock));
 	save_item(NAME(m_data));
 	save_item(NAME(m_vclk));
 	save_item(NAME(m_reset));
-	save_item(NAME(m_prescaler));
+	save_item(NAME(m_s1));
+	save_item(NAME(m_s2));
 	save_item(NAME(m_bitwidth));
 	save_item(NAME(m_signal));
 	save_item(NAME(m_step));
@@ -122,9 +136,6 @@ void msm5205_device::device_reset()
 	m_reset   = 0;
 	m_signal  = 0;
 	m_step    = 0;
-
-	/* timer and bitwidth set */
-	playmode_w(m_select);
 }
 
 
@@ -170,17 +181,17 @@ void msm5205_device::compute_tables()
 	}
 }
 
-/* timer callback at VCLK low edge on MSM5205 (at rising edge on MSM6585) */
+// timer callback at VCK low edge on MSM5205 (at rising edge on MSM6585)
 TIMER_CALLBACK_MEMBER( msm5205_device::vclk_callback )
 {
 	int val;
 	int new_signal;
 
-	/* callback user handler and latch next data */
+	// callback user handler and latch next data
 	if (!m_vclk_cb.isnull())
 		m_vclk_cb(1);
 
-	/* reset check at last hiedge of VCLK */
+	// reset check at last hiedge of VCK
 	if (m_reset)
 	{
 		new_signal = 0;
@@ -213,19 +224,19 @@ TIMER_CALLBACK_MEMBER( msm5205_device::vclk_callback )
 
 
 /*
- *    Handle an update of the vclk status of a chip (1 is reset ON, 0 is reset OFF)
+ *    Handle an update of the VCK status of a chip (1 is reset ON, 0 is reset OFF)
  *    This function can use selector = MSM5205_SEX only
  */
-void msm5205_device::vclk_w(int vclk)
+WRITE_LINE_MEMBER(msm5205_device::vclk_w)
 {
-	if (m_prescaler != 0)
+	if (get_prescaler() != 0)
-		logerror("error: msm5205_vclk_w() called with chip = '%s', but VCLK selected master mode\n", this->device().tag());
+		logerror("Error: vclk_w() called but VCK selected master mode\n");
 	else
 	{
-		if (m_vclk != vclk)
+		if (m_vclk != state)
 		{
-			m_vclk = vclk;
+			m_vclk = state;
-			if (!vclk)
+			if (!state)
 				vclk_callback(this, 0);
 		}
 	}
@@ -235,9 +246,9 @@ void msm5205_device::vclk_w(int vclk)
  *    Handle an update of the reset status of a chip (1 is reset ON, 0 is reset OFF)
  */
 
-void msm5205_device::reset_w(int reset)
+WRITE_LINE_MEMBER(msm5205_device::reset_w)
 {
-	m_reset = reset;
+	m_reset = state;
 }
 
 /*
@@ -257,34 +268,36 @@ WRITE8_MEMBER(msm5205_device::data_w)
 	data_w(data);
 }
 
+int msm5205_device::get_prescaler() const
+{
+	if (m_s1)
+		return m_s2 ? 0 : 64;
+	else
+		return m_s2 ? 48 : 96;
+}
+
+int msm6585_device::get_prescaler() const
+{
+	return (m_s1 ? 20 : 40) * (m_s2 ? 1 : 4);
+}
+
 /*
  *    Handle a change of the selector
  */
 
 void msm5205_device::playmode_w(int select)
 {
-	static const int prescaler_table[2][4] =
-	{
-		{ 96, 48, 64,  0},
-		{160, 40, 80, 20}
-	};
-	int prescaler = prescaler_table[select >> 3 & 1][select & 3];
 	int bitwidth = (select & 4) ? 4 : 3;
 
-	if (m_prescaler != prescaler)
+	if ((select & 3) != ((m_s1 << 1) | m_s2))
 	{
 		m_stream->update();
 
-		m_prescaler = prescaler;
+		m_s1 = BIT(select, 1);
+		m_s2 = BIT(select, 0);
 
 		/* timer set */
-		if (prescaler)
+		notify_clock_changed();
-		{
-			attotime period = attotime::from_hz(m_mod_clock) * prescaler;
-			m_timer->adjust(period, 0, period);
-		}
-		else
-			m_timer->adjust(attotime::never);
 	}
 
 	if (m_bitwidth != bitwidth)
@@ -294,16 +307,43 @@ void msm5205_device::playmode_w(int select)
 	}
 }
 
-
+WRITE_LINE_MEMBER(msm5205_device::s1_w)
-void msm5205_device::change_clock_w(int32_t clock)
 {
-	attotime period;
+	if (m_s1 != bool(state))
+	{
+		m_stream->update();
+		m_s1 = state;
+		notify_clock_changed();
+	}
+}
 
-	m_mod_clock = clock;
+WRITE_LINE_MEMBER(msm5205_device::s2_w)
+{
+	if (m_s2 != bool(state))
+	{
+		m_stream->update();
+		m_s2 = state;
+		notify_clock_changed();
+	}
+}
 
-	period = attotime::from_hz(m_mod_clock) * m_prescaler;
+
+//-------------------------------------------------
+//  device_clock_changed - called when the
+//  device clock is altered in any way
+//-------------------------------------------------
+
+void msm5205_device::device_clock_changed()
+{
+	int prescaler = get_prescaler();
+	if (prescaler != 0)
+	{
+		attotime period = attotime::from_hz(clock()) * prescaler;
 		m_timer->adjust(period, 0, period);
 	}
+	else
+		m_timer->adjust(attotime::never);
+}
 
 
 //-------------------------------------------------

src/devices/sound/msm5205.h

@@ -43,15 +43,15 @@ class msm5205_device : public device_t,
 							public device_sound_interface
 {
 public:
-	msm5205_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock);
+	msm5205_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock);
-	msm5205_device(const machine_config &mconfig, device_type type, const char *name, const char *tag, device_t *owner, uint32_t clock, const char *shortname, const char *source);
+	msm5205_device(const machine_config &mconfig, device_type type, const char *name, const char *tag, device_t *owner, u32 clock, const char *shortname, const char *source);
 	~msm5205_device() {}
 
-	static void set_prescaler_selector(device_t &device, int select) { downcast<msm5205_device &>(device).m_select = select; }
+	static void set_prescaler_selector(device_t &device, int select);
 	template<class _Object> static devcb_base &set_vclk_callback(device_t &device, _Object object) { return downcast<msm5205_device &>(device).m_vclk_cb.set_callback(object); }
 
 	// reset signal should keep for 2cycle of VCLK
-	void reset_w(int reset);
+	DECLARE_WRITE_LINE_MEMBER(reset_w);
 
 	// adpcmata is latched after vclk_interrupt callback
 	void data_w(int data);
@@ -60,17 +60,18 @@ public:
 	// VCLK slave mode option
 	// if VCLK and reset or data is changed at the same time,
 	// call vclk_w after data_w and reset_w.
-	void vclk_w(int vclk);
+	DECLARE_WRITE_LINE_MEMBER(vclk_w);
 
 	// option , selected pin selector
 	void playmode_w(int select);
-
+	DECLARE_WRITE_LINE_MEMBER(s1_w);
-	void change_clock_w(int32_t clock);
+	DECLARE_WRITE_LINE_MEMBER(s2_w);
 
 protected:
 	// device-level overrides
 	virtual void device_start() override;
 	virtual void device_reset() override;
+	virtual void device_clock_changed() override;
 
 	TIMER_CALLBACK_MEMBER(vclk_callback);
 
@@ -78,20 +79,20 @@ protected:
 	virtual void sound_stream_update(sound_stream &stream, stream_sample_t **inputs, stream_sample_t **outputs, int samples) override;
 
 	void compute_tables();
+	virtual int get_prescaler() const;
 
 	// internal state
-	sound_stream * m_stream;    /* number of stream system      */
+	sound_stream * m_stream;    // number of stream system
-	int32_t m_mod_clock;          /* clock rate                   */
+	emu_timer *m_timer;         // VCK callback timer
-	emu_timer *m_timer;         /* VCLK callback timer          */
+	u8 m_data;                  // next adpcm data
-	int32_t m_data;               /* next adpcm data              */
+	bool m_vclk;                // VCK signal (external mode)
-	int32_t m_vclk;               /* vclk signal (external mode)  */
+	bool m_reset;               // reset pin signal
-	int32_t m_reset;              /* reset pin signal             */
+	bool m_s1;                  // prescaler selector S1
-	int32_t m_prescaler;          /* prescaler selector S1 and S2 */
+	bool m_s2;                  // prescaler selector S2
-	int32_t m_bitwidth;           /* bit width selector -3B/4B    */
+	u8 m_bitwidth;              // bit width selector -3B/4B
-	int32_t m_signal;             /* current ADPCM signal         */
+	s32 m_signal;               // current ADPCM signal
-	int32_t m_step;               /* current ADPCM step           */
+	s32 m_step;                 // current ADPCM step
 	int m_diff_lookup[49*16];
-	int m_select;
 	devcb_write_line m_vclk_cb;
 };
 
@@ -100,7 +101,10 @@ extern const device_type MSM5205;
 class msm6585_device : public msm5205_device
 {
 public:
-	msm6585_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock);
+	msm6585_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock);
+
+protected:
+	virtual int get_prescaler() const override;
 
 	// sound stream update overrides
 	virtual void sound_stream_update(sound_stream &stream, stream_sample_t **inputs, stream_sample_t **outputs, int samples) override;

src/mame/drivers/joctronic.cpp

@@ -234,7 +234,7 @@ WRITE8_MEMBER(joctronic_state::resint_w)
 WRITE8_MEMBER(joctronic_state::slalom03_oki_bank_w)
 {
 	m_soundbank->set_entry((data & 0xc0) >> 6);
-	m_oki->playmode_w(BIT(data, 1) ? MSM5205_S48_4B : MSM5205_S96_4B); // to S1 on MSM5205
+	m_oki->s1_w(BIT(data, 1));
 	m_oki->reset_w(BIT(data, 0));
 }
 

src/mame/machine/pce_cd.cpp

@@ -229,7 +229,7 @@ void pce_cd_device::late_setup()
 	}
 
 	// MSM5205 might be initialized after PCE CD as well...
-	m_msm->change_clock_w((PCE_CD_CLOCK / 6) / m_adpcm_clock_divider);
+	m_msm->set_unscaled_clock((PCE_CD_CLOCK / 6) / m_adpcm_clock_divider);
 }
 
 void pce_cd_device::nvram_init(nvram_device &nvram, void *data, size_t size)
@@ -1180,7 +1180,7 @@ WRITE8_MEMBER(pce_cd_device::intf_w)
 			break;
 		case 0x0E:  /* ADPCM playback rate */
 			m_adpcm_clock_divider = 0x10 - (data & 0x0f);
-			m_msm->change_clock_w((PCE_CD_CLOCK / 6) / m_adpcm_clock_divider);
+			m_msm->set_unscaled_clock((PCE_CD_CLOCK / 6) / m_adpcm_clock_divider);
 			break;
 		case 0x0F:  /* ADPCM and CD audio fade timer */
 			/* TODO: timers needs HW tests */