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-rw-r--r--src/mame/audio/segasnd.cpp906
1 files changed, 906 insertions, 0 deletions
diff --git a/src/mame/audio/segasnd.cpp b/src/mame/audio/segasnd.cpp
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index 00000000000..97fdf3a1f41
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+++ b/src/mame/audio/segasnd.cpp
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+// license:BSD-3-Clause
+// copyright-holders:Aaron Giles
+/***************************************************************************
+
+ segasnd.c
+
+ Sound boards for early Sega G-80 based games.
+
+***************************************************************************/
+
+#include "emu.h"
+#include "sound/sp0250.h"
+#include "segasnd.h"
+
+
+#define VERBOSE 0
+#define LOG(x) do { if (VERBOSE) logerror x; } while (0)
+
+
+/***************************************************************************
+ CONSTANTS
+***************************************************************************/
+
+#define SPEECH_MASTER_CLOCK 3120000
+
+#define USB_MASTER_CLOCK 6000000
+#define USB_2MHZ_CLOCK (USB_MASTER_CLOCK/3)
+#define USB_PCS_CLOCK (USB_2MHZ_CLOCK/2)
+#define USB_GOS_CLOCK (USB_2MHZ_CLOCK/16/4)
+#define MM5837_CLOCK 100000
+
+#define SAMPLE_RATE (USB_2MHZ_CLOCK/8)
+
+
+
+/***************************************************************************
+ INLINE FUNCTIONS
+***************************************************************************/
+
+INLINE void configure_filter(g80_filter_state *state, double r, double c)
+{
+ state->capval = 0;
+ state->exponent = 1.0 - exp(-1.0 / (r * c * SAMPLE_RATE));
+}
+
+
+INLINE double step_rc_filter(g80_filter_state *state, double input)
+{
+ state->capval += (input - state->capval) * state->exponent;
+ return state->capval;
+}
+
+
+INLINE double step_cr_filter(g80_filter_state *state, double input)
+{
+ double result = (input - state->capval);
+ state->capval += (input - state->capval) * state->exponent;
+ return result;
+}
+
+
+
+/***************************************************************************
+ SPEECH BOARD
+***************************************************************************/
+
+const device_type SEGASPEECH = &device_creator<speech_sound_device>;
+
+speech_sound_device::speech_sound_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock)
+ : device_t(mconfig, SEGASPEECH, "Sega Speech Sound Board", tag, owner, clock, "sega_speech_sound", __FILE__),
+ device_sound_interface(mconfig, *this),
+ m_drq(0),
+ m_latch(0),
+ m_t0(0),
+ m_p2(0),
+ m_speech(NULL)
+{
+}
+
+//-------------------------------------------------
+// device_start - device-specific startup
+//-------------------------------------------------
+
+void speech_sound_device::device_start()
+{
+ m_speech = machine().root_device().memregion("speech")->base();
+
+ save_item(NAME(m_latch));
+ save_item(NAME(m_t0));
+ save_item(NAME(m_p2));
+ save_item(NAME(m_drq));
+}
+
+
+/*************************************
+ *
+ * i8035 port accessors
+ *
+ *************************************/
+
+
+
+READ8_MEMBER( speech_sound_device::t0_r )
+{
+ return m_t0;
+}
+
+READ8_MEMBER( speech_sound_device::t1_r )
+{
+ return m_drq;
+}
+
+READ8_MEMBER( speech_sound_device::p1_r )
+{
+ return m_latch & 0x7f;
+}
+
+READ8_MEMBER( speech_sound_device::rom_r )
+{
+ return m_speech[0x100 * (m_p2 & 0x3f) + offset];
+}
+
+WRITE8_MEMBER( speech_sound_device::p1_w )
+{
+ if (!(data & 0x80))
+ m_t0 = 0;
+}
+
+WRITE8_MEMBER( speech_sound_device::p2_w )
+{
+ m_p2 = data;
+}
+
+
+
+/*************************************
+ *
+ * i8035 port accessors
+ *
+ *************************************/
+
+WRITE_LINE_MEMBER(speech_sound_device::drq_w)
+{
+ m_drq = (state == ASSERT_LINE);
+}
+
+
+
+/*************************************
+ *
+ * External access
+ *
+ *************************************/
+
+TIMER_CALLBACK_MEMBER( speech_sound_device::delayed_speech_w )
+{
+ int data = param;
+ UINT8 old = m_latch;
+
+ /* all 8 bits are latched */
+ m_latch = data;
+
+ /* the high bit goes directly to the INT line */
+ machine().device("audiocpu")->execute().set_input_line(0, (data & 0x80) ? CLEAR_LINE : ASSERT_LINE);
+
+ /* a clock on the high bit clocks a 1 into T0 */
+ if (!(old & 0x80) && (data & 0x80))
+ m_t0 = 1;
+}
+
+
+WRITE8_MEMBER( speech_sound_device::data_w )
+{
+ space.machine().scheduler().synchronize(timer_expired_delegate(FUNC(speech_sound_device::delayed_speech_w), this), data);
+}
+
+
+WRITE8_MEMBER( speech_sound_device::control_w )
+{
+ LOG(("Speech control = %X\n", data));
+}
+
+
+//-------------------------------------------------
+// sound_stream_update - handle a stream update
+//-------------------------------------------------
+
+void speech_sound_device::sound_stream_update(sound_stream &stream, stream_sample_t **inputs, stream_sample_t **outputs, int samples)
+{
+}
+
+
+/*************************************
+ *
+ * Speech board address maps
+ *
+ *************************************/
+
+static ADDRESS_MAP_START( speech_map, AS_PROGRAM, 8, driver_device )
+ AM_RANGE(0x0000, 0x07ff) AM_MIRROR(0x0800) AM_ROM
+ADDRESS_MAP_END
+
+
+static ADDRESS_MAP_START( speech_portmap, AS_IO, 8, driver_device )
+ AM_RANGE(0x00, 0xff) AM_DEVREAD("segaspeech", speech_sound_device, rom_r)
+ AM_RANGE(0x00, 0xff) AM_DEVWRITE("speech", sp0250_device, write)
+ AM_RANGE(MCS48_PORT_P1, MCS48_PORT_P1) AM_DEVREADWRITE("segaspeech", speech_sound_device, p1_r, p1_w)
+ AM_RANGE(MCS48_PORT_P2, MCS48_PORT_P2) AM_DEVWRITE("segaspeech", speech_sound_device, p2_w)
+ AM_RANGE(MCS48_PORT_T0, MCS48_PORT_T0) AM_DEVREAD("segaspeech", speech_sound_device, t0_r)
+ AM_RANGE(MCS48_PORT_T1, MCS48_PORT_T1) AM_DEVREAD("segaspeech", speech_sound_device, t1_r)
+ADDRESS_MAP_END
+
+
+/*************************************
+ *
+ * Speech board machine drivers
+ *
+ *************************************/
+
+MACHINE_CONFIG_FRAGMENT( sega_speech_board )
+
+ /* CPU for the speech board */
+ MCFG_CPU_ADD("audiocpu", I8035, SPEECH_MASTER_CLOCK) /* divide by 15 in CPU */
+ MCFG_CPU_PROGRAM_MAP(speech_map)
+ MCFG_CPU_IO_MAP(speech_portmap)
+
+ /* sound hardware */
+ MCFG_SOUND_ADD("segaspeech", SEGASPEECH, 0)
+ MCFG_SOUND_ADD("speech", SP0250, SPEECH_MASTER_CLOCK)
+ MCFG_SP0250_DRQ_CALLBACK(DEVWRITELINE("segaspeech", speech_sound_device, drq_w))
+ MCFG_SOUND_ROUTE(ALL_OUTPUTS, "mono", 1.0)
+MACHINE_CONFIG_END
+
+
+
+/***************************************************************************
+ UNIVERSAL SOUND BOARD
+***************************************************************************/
+
+const device_type SEGAUSB = &device_creator<usb_sound_device>;
+
+usb_sound_device::usb_sound_device(const machine_config &mconfig, device_type type, const char *name, const char *tag, device_t *owner, UINT32 clock, const char *shortname, const char *source)
+ : device_t(mconfig, type, name, tag, owner, clock, shortname, source),
+ device_sound_interface(mconfig, *this),
+ m_ourcpu(*this, "ourcpu"),
+ m_stream(NULL),
+ m_in_latch(0),
+ m_out_latch(0),
+ m_last_p2_value(0),
+ m_program_ram(*this, "pgmram"),
+ m_work_ram(*this, "workram"),
+ m_work_ram_bank(0),
+ m_t1_clock(0),
+ m_t1_clock_mask(0),
+ m_noise_shift(0),
+ m_noise_state(0),
+ m_noise_subcount(0)
+{
+}
+
+usb_sound_device::usb_sound_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock)
+ : device_t(mconfig, SEGAUSB, "Sega Universal Sound Board", tag, owner, clock, "segausb", __FILE__),
+ device_sound_interface(mconfig, *this),
+ m_ourcpu(*this, "ourcpu"),
+ m_program_ram(*this, "pgmram"),
+ m_work_ram(*this, "workram")
+{
+}
+
+//-------------------------------------------------
+// device_start - device-specific startup
+//-------------------------------------------------
+
+void usb_sound_device::device_start()
+{
+ g80_filter_state temp;
+ int tchan, tgroup;
+
+ /* find the CPU we are associated with */
+ m_maincpu = machine().device("maincpu");
+ assert(m_maincpu != NULL);
+
+ /* create a sound stream */
+ m_stream = machine().sound().stream_alloc(*this, 0, 1, SAMPLE_RATE);
+
+ /* initialize state */
+ m_noise_shift = 0x15555;
+
+ for (tgroup = 0; tgroup < 3; tgroup++)
+ {
+ timer8253 *g = &m_timer_group[tgroup];
+ configure_filter(&g->chan_filter[0], 10e3, 1e-6);
+ configure_filter(&g->chan_filter[1], 10e3, 1e-6);
+ configure_filter(&g->gate1, 100e3, 0.01e-6);
+ configure_filter(&g->gate2, 2 * 100e3, 0.01e-6);
+ }
+
+ configure_filter(&temp, 100e3, 0.01e-6);
+ m_gate_rc1_exp[0] = temp.exponent;
+ configure_filter(&temp, 1e3, 0.01e-6);
+ m_gate_rc1_exp[1] = temp.exponent;
+ configure_filter(&temp, 2 * 100e3, 0.01e-6);
+ m_gate_rc2_exp[0] = temp.exponent;
+ configure_filter(&temp, 2 * 1e3, 0.01e-6);
+ m_gate_rc2_exp[1] = temp.exponent;
+
+ configure_filter(&m_noise_filters[0], 2.7e3 + 2.7e3, 1.0e-6);
+ configure_filter(&m_noise_filters[1], 2.7e3 + 1e3, 0.30e-6);
+ configure_filter(&m_noise_filters[2], 2.7e3 + 270, 0.15e-6);
+ configure_filter(&m_noise_filters[3], 2.7e3 + 0, 0.082e-6);
+ configure_filter(&m_noise_filters[4], 33e3, 0.1e-6);
+
+ configure_filter(&m_final_filter, 100e3, 4.7e-6);
+
+ /* register for save states */
+ save_item(NAME(m_in_latch));
+ save_item(NAME(m_out_latch));
+ save_item(NAME(m_last_p2_value));
+ save_item(NAME(m_work_ram_bank));
+ save_item(NAME(m_t1_clock));
+
+ for (tgroup = 0; tgroup < 3; tgroup++)
+ {
+ timer8253 *group = &m_timer_group[tgroup];
+ for (tchan = 0; tchan < 3; tchan++)
+ {
+ timer8253_channel *channel = &group->chan[tchan];
+ save_item(NAME(channel->holding), tgroup * 3 + tchan);
+ save_item(NAME(channel->latchmode), tgroup * 3 + tchan);
+ save_item(NAME(channel->latchtoggle), tgroup * 3 + tchan);
+ save_item(NAME(channel->clockmode), tgroup * 3 + tchan);
+ save_item(NAME(channel->bcdmode), tgroup * 3 + tchan);
+ save_item(NAME(channel->output), tgroup * 3 + tchan);
+ save_item(NAME(channel->lastgate), tgroup * 3 + tchan);
+ save_item(NAME(channel->gate), tgroup * 3 + tchan);
+ save_item(NAME(channel->subcount), tgroup * 3 + tchan);
+ save_item(NAME(channel->count), tgroup * 3 + tchan);
+ save_item(NAME(channel->remain), tgroup * 3 + tchan);
+ }
+ save_item(NAME(group->env), tgroup);
+ save_item(NAME(group->chan_filter[0].capval), tgroup);
+ save_item(NAME(group->chan_filter[1].capval), tgroup);
+ save_item(NAME(group->gate1.capval), tgroup);
+ save_item(NAME(group->gate2.capval), tgroup);
+ save_item(NAME(group->config), tgroup);
+ }
+
+ save_item(NAME(m_timer_mode));
+ save_item(NAME(m_noise_shift));
+ save_item(NAME(m_noise_state));
+ save_item(NAME(m_noise_subcount));
+ save_item(NAME(m_final_filter.capval));
+ save_item(NAME(m_noise_filters[0].capval));
+ save_item(NAME(m_noise_filters[1].capval));
+ save_item(NAME(m_noise_filters[2].capval));
+ save_item(NAME(m_noise_filters[3].capval));
+ save_item(NAME(m_noise_filters[4].capval));
+}
+
+//-------------------------------------------------
+// device_reset - device-specific reset
+//-------------------------------------------------
+
+void usb_sound_device::device_reset()
+{
+ /* halt the USB CPU at reset time */
+ m_ourcpu->set_input_line(INPUT_LINE_RESET, ASSERT_LINE);
+
+ /* start the clock timer */
+ m_t1_clock_mask = 0x10;
+}
+
+/*************************************
+ *
+ * Initialization/reset
+ *
+ *************************************/
+
+TIMER_DEVICE_CALLBACK_MEMBER( usb_sound_device::increment_t1_clock_timer_cb )
+{
+ /* only increment if it is not being forced clear */
+ if (!(m_last_p2_value & 0x80))
+ m_t1_clock++;
+}
+
+/*************************************
+ *
+ * External access
+ *
+ *************************************/
+
+READ8_MEMBER( usb_sound_device::status_r )
+{
+ LOG(("%04X:usb_data_r = %02X\n", m_maincpu->safe_pc(), (m_out_latch & 0x81) | (m_in_latch & 0x7e)));
+
+ m_maincpu->execute().adjust_icount(-200);
+
+ /* only bits 0 and 7 are controlled by the I8035; the remaining */
+ /* bits 1-6 reflect the current input latch values */
+ return (m_out_latch & 0x81) | (m_in_latch & 0x7e);
+}
+
+
+TIMER_CALLBACK_MEMBER( usb_sound_device::delayed_usb_data_w )
+{
+ int data = param;
+
+ /* look for rising/falling edges of bit 7 to control the RESET line */
+ m_ourcpu->set_input_line(INPUT_LINE_RESET, (data & 0x80) ? ASSERT_LINE : CLEAR_LINE);
+
+ /* if the CLEAR line is set, the low 7 bits of the input are ignored */
+ if ((m_last_p2_value & 0x40) == 0)
+ data &= ~0x7f;
+
+ /* update the effective input latch */
+ m_in_latch = data;
+}
+
+
+WRITE8_MEMBER( usb_sound_device::data_w )
+{
+ LOG(("%04X:usb_data_w = %02X\n", m_maincpu->safe_pc(), data));
+ space.machine().scheduler().synchronize(timer_expired_delegate(FUNC(usb_sound_device::delayed_usb_data_w), this), data);
+
+ /* boost the interleave so that sequences can be sent */
+ space.machine().scheduler().boost_interleave(attotime::zero, attotime::from_usec(250));
+}
+
+
+READ8_MEMBER( usb_sound_device::ram_r )
+{
+ return m_program_ram[offset];
+}
+
+
+WRITE8_MEMBER( usb_sound_device::ram_w )
+{
+ if (m_in_latch & 0x80)
+ m_program_ram[offset] = data;
+ else
+ LOG(("%04X:sega_usb_ram_w(%03X) = %02X while /LOAD disabled\n", m_maincpu->safe_pc(), offset, data));
+}
+
+
+
+/*************************************
+ *
+ * I8035 port accesses
+ *
+ *************************************/
+
+READ8_MEMBER( usb_sound_device::p1_r )
+{
+ /* bits 0-6 are inputs and map to bits 0-6 of the input latch */
+ if ((m_in_latch & 0x7f) != 0)
+ LOG(("%03X: P1 read = %02X\n", m_maincpu->safe_pc(), m_in_latch & 0x7f));
+ return m_in_latch & 0x7f;
+}
+
+
+WRITE8_MEMBER( usb_sound_device::p1_w )
+{
+ /* bit 7 maps to bit 0 on the output latch */
+ m_out_latch = (m_out_latch & 0xfe) | (data >> 7);
+ LOG(("%03X: P1 write = %02X\n", m_maincpu->safe_pc(), data));
+}
+
+
+WRITE8_MEMBER( usb_sound_device::p2_w )
+{
+ UINT8 old = m_last_p2_value;
+ m_last_p2_value = data;
+
+ /* low 2 bits control the bank of work RAM we are addressing */
+ m_work_ram_bank = data & 3;
+
+ /* bit 6 controls the "ready" bit output to the host */
+ /* it also clears the input latch from the host (active low) */
+ m_out_latch = ((data & 0x40) << 1) | (m_out_latch & 0x7f);
+ if ((data & 0x40) == 0)
+ m_in_latch = 0;
+
+ /* bit 7 controls the reset on the upper counter at U33 */
+ if ((old & 0x80) && !(data & 0x80))
+ m_t1_clock = 0;
+
+ LOG(("%03X: P2 write -> bank=%d ready=%d clock=%d\n", m_maincpu->safe_pc(), data & 3, (data >> 6) & 1, (data >> 7) & 1));
+}
+
+
+READ8_MEMBER( usb_sound_device::t1_r )
+{
+ /* T1 returns 1 based on the value of the T1 clock; the exact */
+ /* pattern is determined by one or more jumpers on the board. */
+ return (m_t1_clock & m_t1_clock_mask) != 0;
+}
+
+
+
+/*************************************
+ *
+ * Sound generation
+ *
+ *************************************/
+
+INLINE void clock_channel(timer8253_channel *ch)
+{
+ UINT8 lastgate = ch->lastgate;
+
+ /* update the gate */
+ ch->lastgate = ch->gate;
+
+ /* if we're holding, skip */
+ if (ch->holding)
+ return;
+
+ /* switch off the clock mode */
+ switch (ch->clockmode)
+ {
+ /* oneshot; waits for trigger to restart */
+ case 1:
+ if (!lastgate && ch->gate)
+ {
+ ch->output = 0;
+ ch->remain = ch->count;
+ }
+ else
+ {
+ if (--ch->remain == 0)
+ ch->output = 1;
+ }
+ break;
+
+ /* square wave: counts down by 2 and toggles output */
+ case 3:
+ ch->remain = (ch->remain - 1) & ~1;
+ if (ch->remain == 0)
+ {
+ ch->output ^= 1;
+ ch->remain = ch->count;
+ }
+ break;
+ }
+}
+
+
+/*************************************
+ *
+ * USB timer and envelope controls
+ *
+ *************************************/
+
+void usb_sound_device::timer_w(int which, UINT8 offset, UINT8 data)
+{
+ timer8253 *g = &m_timer_group[which];
+ timer8253_channel *ch;
+ int was_holding;
+
+ m_stream->update();
+
+ /* switch off the offset */
+ switch (offset)
+ {
+ case 0:
+ case 1:
+ case 2:
+ ch = &g->chan[offset];
+ was_holding = ch->holding;
+
+ /* based on the latching mode */
+ switch (ch->latchmode)
+ {
+ case 1: /* low word only */
+ ch->count = data;
+ ch->holding = FALSE;
+ break;
+
+ case 2: /* high word only */
+ ch->count = data << 8;
+ ch->holding = FALSE;
+ break;
+
+ case 3: /* low word followed by high word */
+ if (ch->latchtoggle == 0)
+ {
+ ch->count = (ch->count & 0xff00) | (data & 0x00ff);
+ ch->latchtoggle = 1;
+ }
+ else
+ {
+ ch->count = (ch->count & 0x00ff) | (data << 8);
+ ch->holding = FALSE;
+ ch->latchtoggle = 0;
+ }
+ break;
+ }
+
+ /* if we're not holding, load the initial count for some modes */
+ if (was_holding && !ch->holding)
+ ch->remain = 1;
+ break;
+
+ case 3:
+ /* break out the components */
+ if (((data & 0xc0) >> 6) < 3)
+ {
+ ch = &g->chan[(data & 0xc0) >> 6];
+
+ /* extract the bits */
+ ch->holding = TRUE;
+ ch->latchmode = (data >> 4) & 3;
+ ch->clockmode = (data >> 1) & 7;
+ ch->bcdmode = (data >> 0) & 1;
+ ch->latchtoggle = 0;
+ ch->output = (ch->clockmode == 1);
+ }
+ break;
+ }
+}
+
+
+void usb_sound_device::env_w(int which, UINT8 offset, UINT8 data)
+{
+ timer8253 *g = &m_timer_group[which];
+
+ m_stream->update();
+
+ if (offset < 3)
+ g->env[offset] = (double)data;
+ else
+ g->config = data & 1;
+}
+
+
+
+/*************************************
+ *
+ * USB work RAM access
+ *
+ *************************************/
+
+READ8_MEMBER( usb_sound_device::workram_r )
+{
+ offset += 256 * m_work_ram_bank;
+ return m_work_ram[offset];
+}
+
+
+WRITE8_MEMBER( usb_sound_device::workram_w )
+{
+ offset += 256 * m_work_ram_bank;
+ m_work_ram[offset] = data;
+
+ /* writes to the low 32 bytes go to various controls */
+ switch (offset & ~3)
+ {
+ case 0x00: /* CTC0 */
+ timer_w(0, offset & 3, data);
+ break;
+
+ case 0x04: /* ENV0 */
+ env_w(0, offset & 3, data);
+ break;
+
+ case 0x08: /* CTC1 */
+ timer_w(1, offset & 3, data);
+ break;
+
+ case 0x0c: /* ENV1 */
+ env_w(1, offset & 3, data);
+ break;
+
+ case 0x10: /* CTC2 */
+ timer_w(2, offset & 3, data);
+ break;
+
+ case 0x14: /* ENV2 */
+ env_w(2, offset & 3, data);
+ break;
+ }
+}
+
+//-------------------------------------------------
+// sound_stream_update - handle a stream update
+//-------------------------------------------------
+
+void usb_sound_device::sound_stream_update(sound_stream &stream, stream_sample_t **inputs, stream_sample_t **outputs, int samples)
+{
+ stream_sample_t *dest = outputs[0];
+
+ /* iterate over samples */
+ while (samples--)
+ {
+ double noiseval;
+ double sample = 0;
+ int group;
+ int step;
+
+
+ /*----------------
+ Noise Source
+ ----------------
+
+ RC
+ MM5837 ---> FILTER ---> CR FILTER ---> 3.2x AMP ---> NOISE
+ LADDER
+ */
+
+ /* update the noise source */
+ for (step = USB_2MHZ_CLOCK / SAMPLE_RATE; step >= m_noise_subcount; step -= m_noise_subcount)
+ {
+ m_noise_shift = (m_noise_shift << 1) | (((m_noise_shift >> 13) ^ (m_noise_shift >> 16)) & 1);
+ m_noise_state = (m_noise_shift >> 16) & 1;
+ m_noise_subcount = USB_2MHZ_CLOCK / MM5837_CLOCK;
+ }
+ m_noise_subcount -= step;
+
+ /* update the filtered noise value -- this is just an approximation to the pink noise filter */
+ /* being applied on the PCB, but it sounds pretty close */
+ m_noise_filters[0].capval = 0.99765 * m_noise_filters[0].capval + m_noise_state * 0.0990460;
+ m_noise_filters[1].capval = 0.96300 * m_noise_filters[1].capval + m_noise_state * 0.2965164;
+ m_noise_filters[2].capval = 0.57000 * m_noise_filters[2].capval + m_noise_state * 1.0526913;
+ noiseval = m_noise_filters[0].capval + m_noise_filters[1].capval + m_noise_filters[2].capval + m_noise_state * 0.1848;
+
+ /* final output goes through a CR filter; the scaling factor is arbitrary to get the noise to the */
+ /* correct relative volume */
+ noiseval = step_cr_filter(&m_noise_filters[4], noiseval);
+ noiseval *= 0.075;
+
+ /* there are 3 identical groups of circuits, each with its own 8253 */
+ for (group = 0; group < 3; group++)
+ {
+ timer8253 *g = &m_timer_group[group];
+ double chan0, chan1, chan2, mix;
+
+
+ /*-------------
+ Channel 0
+ -------------
+
+ 8253 CR AD7524
+ OUT0 ---> FILTER ---> BUFFER---> VRef ---> 100k ---> mix
+ */
+
+ /* channel 0 clocks with the PCS clock */
+ for (step = USB_2MHZ_CLOCK / SAMPLE_RATE; step >= g->chan[0].subcount; step -= g->chan[0].subcount)
+ {
+ g->chan[0].subcount = USB_2MHZ_CLOCK / USB_PCS_CLOCK;
+ g->chan[0].gate = 1;
+ clock_channel(&g->chan[0]);
+ }
+ g->chan[0].subcount -= step;
+
+ /* channel 0 is mixed in with a resistance of 100k */
+ chan0 = step_cr_filter(&g->chan_filter[0], g->chan[0].output) * g->env[0] * (1.0/100.0);
+
+
+ /*-------------
+ Channel 1
+ -------------
+
+ 8253 CR AD7524
+ OUT1 ---> FILTER ---> BUFFER---> VRef ---> 100k ---> mix
+ */
+
+ /* channel 1 clocks with the PCS clock */
+ for (step = USB_2MHZ_CLOCK / SAMPLE_RATE; step >= g->chan[1].subcount; step -= g->chan[1].subcount)
+ {
+ g->chan[1].subcount = USB_2MHZ_CLOCK / USB_PCS_CLOCK;
+ g->chan[1].gate = 1;
+ clock_channel(&g->chan[1]);
+ }
+ g->chan[1].subcount -= step;
+
+ /* channel 1 is mixed in with a resistance of 100k */
+ chan1 = step_cr_filter(&g->chan_filter[1], g->chan[1].output) * g->env[1] * (1.0/100.0);
+
+
+ /*-------------
+ Channel 2
+ -------------
+
+ If timer_mode == 0:
+
+ SWITCHED AD7524
+ NOISE ---> RC ---> 1.56x AMP ---> INVERTER ---> VRef ---> 33k ---> mix
+ FILTERS
+
+ If timer mode == 1:
+
+ AD7524 SWITCHED
+ NOISE ---> INVERTER ---> VRef ---> 33k ---> mix ---> INVERTER ---> RC ---> 1.56x AMP ---> finalmix
+ FILTERS
+ */
+
+ /* channel 2 clocks with the 2MHZ clock and triggers with the GOS clock */
+ for (step = 0; step < USB_2MHZ_CLOCK / SAMPLE_RATE; step++)
+ {
+ if (g->chan[2].subcount-- == 0)
+ {
+ g->chan[2].subcount = USB_2MHZ_CLOCK / USB_GOS_CLOCK / 2 - 1;
+ g->chan[2].gate = !g->chan[2].gate;
+ }
+ clock_channel(&g->chan[2]);
+ }
+
+ /* the exponents for the gate filters are determined by channel 2's output */
+ g->gate1.exponent = m_gate_rc1_exp[g->chan[2].output];
+ g->gate2.exponent = m_gate_rc2_exp[g->chan[2].output];
+
+ /* based on the envelope mode, we do one of two things with source 2 */
+ if (g->config == 0)
+ {
+ chan2 = step_rc_filter(&g->gate2, step_rc_filter(&g->gate1, noiseval)) * -1.56 * g->env[2] * (1.0/33.0);
+ mix = chan0 + chan1 + chan2;
+ }
+ else
+ {
+ chan2 = -noiseval * g->env[2] * (1.0/33.0);
+ mix = chan0 + chan1 + chan2;
+ mix = step_rc_filter(&g->gate2, step_rc_filter(&g->gate1, -mix)) * 1.56;
+ }
+
+ /* accumulate the sample */
+ sample += mix;
+ }
+
+
+ /*-------------
+ Final mix
+ -------------
+
+ INPUTS
+ EQUAL ---> 1.2x INVERTER ---> CR FILTER ---> out
+ WEIGHT
+
+ */
+ *dest++ = 4000 * step_cr_filter(&m_final_filter, sample);
+ }
+}
+
+
+/*************************************
+ *
+ * USB address maps
+ *
+ *************************************/
+
+static ADDRESS_MAP_START( usb_map, AS_PROGRAM, 8, usb_sound_device )
+ AM_RANGE(0x0000, 0x0fff) AM_RAM AM_SHARE("pgmram")
+ADDRESS_MAP_END
+
+static ADDRESS_MAP_START( usb_portmap, AS_IO, 8, usb_sound_device )
+ AM_RANGE(0x00, 0xff) AM_READWRITE(workram_r, workram_w) AM_SHARE("workram")
+ AM_RANGE(MCS48_PORT_P1, MCS48_PORT_P1) AM_READWRITE(p1_r, p1_w)
+ AM_RANGE(MCS48_PORT_P2, MCS48_PORT_P2) AM_WRITE(p2_w)
+ AM_RANGE(MCS48_PORT_T1, MCS48_PORT_T1) AM_READ(t1_r)
+ADDRESS_MAP_END
+
+
+/*************************************
+ *
+ * USB machine drivers
+ *
+ *************************************/
+
+MACHINE_CONFIG_FRAGMENT( segausb )
+
+ /* CPU for the usb board */
+ MCFG_CPU_ADD("ourcpu", I8035, USB_MASTER_CLOCK) /* divide by 15 in CPU */
+ MCFG_CPU_PROGRAM_MAP(usb_map)
+ MCFG_CPU_IO_MAP(usb_portmap)
+
+ MCFG_TIMER_DRIVER_ADD_PERIODIC("usb_timer", usb_sound_device, increment_t1_clock_timer_cb, attotime::from_hz(USB_2MHZ_CLOCK / 256))
+MACHINE_CONFIG_END
+
+machine_config_constructor usb_sound_device::device_mconfig_additions() const
+{
+ return MACHINE_CONFIG_NAME( segausb );
+}
+
+const device_type SEGAUSBROM = &device_creator<usb_rom_sound_device>;
+
+usb_rom_sound_device::usb_rom_sound_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock)
+ : usb_sound_device(mconfig, SEGAUSBROM, "Sega Universal Sound Board with ROM", tag, owner, clock, "segausbrom", __FILE__)
+{
+}
+
+static ADDRESS_MAP_START( usb_map_rom, AS_PROGRAM, 8, usb_sound_device )
+ AM_RANGE(0x0000, 0x0fff) AM_ROM AM_REGION(":usbcpu", 0)
+ADDRESS_MAP_END
+
+MACHINE_CONFIG_FRAGMENT( segausb_rom )
+
+ /* CPU for the usb board */
+ MCFG_CPU_ADD("ourcpu", I8035, USB_MASTER_CLOCK) /* divide by 15 in CPU */
+ MCFG_CPU_PROGRAM_MAP(usb_map_rom)
+ MCFG_CPU_IO_MAP(usb_portmap)
+
+ MCFG_TIMER_DRIVER_ADD_PERIODIC("usb_timer", usb_sound_device, increment_t1_clock_timer_cb, attotime::from_hz(USB_2MHZ_CLOCK / 256))
+MACHINE_CONFIG_END
+
+machine_config_constructor usb_rom_sound_device::device_mconfig_additions() const
+{
+ return MACHINE_CONFIG_NAME( segausb_rom );
+}