diff options
Diffstat (limited to 'src/mame/audio/segasnd.c')
-rw-r--r-- | src/mame/audio/segasnd.c | 938 |
1 files changed, 938 insertions, 0 deletions
diff --git a/src/mame/audio/segasnd.c b/src/mame/audio/segasnd.c new file mode 100644 index 00000000000..fc416cbd63d --- /dev/null +++ b/src/mame/audio/segasnd.c @@ -0,0 +1,938 @@ +/*************************************************************************** + + segag80.c + + Sound boards for early Sega G-80 based games. + + Copyright (c) 1996-2007, Nicola Salmoria and the MAME Team. + Visit http://mamedev.org for licensing and usage restrictions. + +***************************************************************************/ + +#include "driver.h" +#include "streams.h" +#include "segag80v.h" +#include "cpu/i8039/i8039.h" +#include "sound/sp0250.h" +#include "segasnd.h" +#include <math.h> + + +#define LOG(x) /* logerror x */ + + +/*************************************************************************** + 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) + + + +/*************************************************************************** + TYPE DEFINITIONS +***************************************************************************/ + +typedef struct _filter_state filter_state; +struct _filter_state +{ + double capval; /* current capacitor value */ + double exponent; /* constant exponent */ +}; + + +typedef struct _timer8253_channel timer8253_channel; +struct _timer8253_channel +{ + UINT8 holding; /* holding until counts written? */ + UINT8 latchmode; /* latching mode */ + UINT8 latchtoggle; /* latching state */ + UINT8 clockmode; /* clocking mode */ + UINT8 bcdmode; /* BCD mode? */ + UINT8 output; /* current output value */ + UINT8 lastgate; /* previous gate value */ + UINT8 gate; /* current gate value */ + UINT8 subcount; /* subcount (2MHz clocks per input clock) */ + UINT16 count; /* initial count */ + UINT16 remain; /* current down counter value */ +}; + + +typedef struct _timer8253 timer8253; +struct _timer8253 +{ + timer8253_channel chan[3]; /* three channels' worth of information */ + double env[3]; /* envelope value for each channel */ + filter_state chan_filter[2]; /* filter states for the first two channels */ + filter_state gate1; /* first RC filter state */ + filter_state gate2; /* second RC filter state */ + UINT8 config; /* configuration for this timer */ +}; + + +typedef struct _usb_state usb_state; +struct _usb_state +{ + sound_stream * stream; /* output stream */ + UINT8 cpunum; /* CPU index of the 8035 */ + UINT8 in_latch; /* input latch */ + UINT8 out_latch; /* output latch */ + UINT8 last_p2_value; /* current P2 output value */ + UINT8 * program_ram; /* pointer to program RAM */ + UINT8 * work_ram; /* pointer to work RAM */ + UINT8 work_ram_bank; /* currently selected work RAM bank */ + UINT8 t1_clock; /* T1 clock value */ + UINT8 t1_clock_mask; /* T1 clock mask (configured via jumpers) */ + timer8253 timer_group[3]; /* 3 groups of timers */ + UINT8 timer_mode[3]; /* mode control for each group */ + UINT32 noise_shift; + UINT8 noise_state; + UINT8 noise_subcount; + double gate_rc1_exp[2]; + double gate_rc2_exp[2]; + filter_state final_filter; + filter_state noise_filters[5]; +}; + + + +/*************************************************************************** + GLOBAL VARIABLES +***************************************************************************/ + +/* SP0250-based speech board */ +static UINT8 speech_latch, speech_t0, speech_p2, speech_drq; + +/* Universal sound board */ +static usb_state usb; + + + +/*************************************************************************** + INLINE FUNCTIONS +***************************************************************************/ + +INLINE void configure_filter(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(filter_state *state, double input) +{ + state->capval += (input - state->capval) * state->exponent; + return state->capval; +} + + +INLINE double step_cr_filter(filter_state *state, double input) +{ + double result = (input - state->capval); + state->capval += (input - state->capval) * state->exponent; + return result; +} + + + +/*************************************************************************** + SPEECH BOARD +***************************************************************************/ + + +/************************************* + * + * i8035 port accessors + * + *************************************/ + +static READ8_HANDLER( speech_t0_r ) +{ + return speech_t0; +} + +static READ8_HANDLER( speech_t1_r ) +{ + return speech_drq; +} + +static READ8_HANDLER( speech_p1_r ) +{ + return speech_latch & 0x7f; +} + +static READ8_HANDLER( speech_rom_r ) +{ + return memory_region(REGION_SOUND1)[0x100 * (speech_p2 & 0x3f) + offset]; +} + +static WRITE8_HANDLER( speech_p1_w ) +{ + if (!(data & 0x80)) + speech_t0 = 0; +} + +static WRITE8_HANDLER( speech_p2_w ) +{ + speech_p2 = data; +} + + + +/************************************* + * + * i8035 port accessors + * + *************************************/ + +static void speech_drq_w(int level) +{ + speech_drq = (level == ASSERT_LINE); +} + + + +/************************************* + * + * External access + * + *************************************/ + +static TIMER_CALLBACK( delayed_speech_w ) +{ + int data = param; + UINT8 old = speech_latch; + + /* all 8 bits are latched */ + speech_latch = data; + + /* the high bit goes directly to the INT line */ + cpunum_set_input_line(1, 0, (data & 0x80) ? CLEAR_LINE : ASSERT_LINE); + + /* a clock on the high bit clocks a 1 into T0 */ + if (!(old & 0x80) && (data & 0x80)) + speech_t0 = 1; +} + + +WRITE8_HANDLER( sega_speech_data_w ) +{ + timer_call_after_resynch(data, delayed_speech_w); +} + + +WRITE8_HANDLER( sega_speech_control_w ) +{ + LOG(("Speech control = %X\n", data)); +} + + + +/************************************* + * + * Speech board address maps + * + *************************************/ + +static ADDRESS_MAP_START( speech_map, ADDRESS_SPACE_PROGRAM, 8 ) + AM_RANGE(0x0000, 0x07ff) AM_MIRROR(0x0800) AM_ROM +ADDRESS_MAP_END + + +static ADDRESS_MAP_START( speech_portmap, ADDRESS_SPACE_IO, 8 ) + AM_RANGE(0x00, 0xff) AM_READ(speech_rom_r) + AM_RANGE(0x00, 0xff) AM_WRITE(sp0250_w) + AM_RANGE(I8039_p1, I8039_p1) AM_READWRITE(speech_p1_r, speech_p1_w) + AM_RANGE(I8039_p2, I8039_p2) AM_WRITE(speech_p2_w) + AM_RANGE(I8039_t0, I8039_t0) AM_READ(speech_t0_r) + AM_RANGE(I8039_t1, I8039_t1) AM_READ(speech_t1_r) +ADDRESS_MAP_END + + + +/************************************* + * + * Speech board sound interfaces + * + *************************************/ + +static struct sp0250_interface sp0250_interface = +{ + speech_drq_w +}; + + + +/************************************* + * + * Speech board machine drivers + * + *************************************/ + +MACHINE_DRIVER_START( sega_speech_board ) + + /* CPU for the speech board */ + MDRV_CPU_ADD(I8035, SPEECH_MASTER_CLOCK/15) /* divide by 15 in CPU */ + MDRV_CPU_PROGRAM_MAP(speech_map, 0) + MDRV_CPU_IO_MAP(speech_portmap, 0) + + /* sound hardware */ + MDRV_SOUND_ADD(SP0250, SPEECH_MASTER_CLOCK) + MDRV_SOUND_CONFIG(sp0250_interface) + MDRV_SOUND_ROUTE(ALL_OUTPUTS, "mono", 1.0) +MACHINE_DRIVER_END + + + +/*************************************************************************** + UNIVERSAL SOUND BOARD +***************************************************************************/ + + +/************************************* + * + * Initialization/reset + * + *************************************/ + +static TIMER_CALLBACK( increment_t1_clock ) +{ + /* only increment if it is not being forced clear */ + if (!(usb.last_p2_value & 0x80)) + usb.t1_clock++; +} + + +void sega_usb_reset(UINT8 t1_clock_mask) +{ + /* halt the USB CPU at reset time */ + cpunum_set_input_line(usb.cpunum, INPUT_LINE_RESET, ASSERT_LINE); + + /* start the clock timer */ + timer_pulse(attotime_mul(ATTOTIME_IN_HZ(USB_2MHZ_CLOCK), 256), 0, increment_t1_clock); + usb.t1_clock_mask = t1_clock_mask; +} + + + +/************************************* + * + * External access + * + *************************************/ + +READ8_HANDLER( sega_usb_status_r ) +{ + LOG(("%04X:usb_data_r = %02X\n", activecpu_get_pc(), (usb.out_latch & 0x81) | (usb.in_latch & 0x7e))); + + activecpu_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 (usb.out_latch & 0x81) | (usb.in_latch & 0x7e); +} + + +static TIMER_CALLBACK( delayed_usb_data_w ) +{ + int data = param; + + /* look for rising/falling edges of bit 7 to control the RESET line */ + cpunum_set_input_line(usb.cpunum, 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 ((usb.last_p2_value & 0x40) == 0) + data &= ~0x7f; + + /* update the effective input latch */ + usb.in_latch = data; +} + + +WRITE8_HANDLER( sega_usb_data_w ) +{ + LOG(("%04X:usb_data_w = %02X\n", activecpu_get_pc(), data)); + timer_call_after_resynch(data, delayed_usb_data_w); + + /* boost the interleave so that sequences can be sent */ + cpu_boost_interleave(attotime_zero, ATTOTIME_IN_USEC(250)); +} + + +READ8_HANDLER( sega_usb_ram_r ) +{ + return usb.program_ram[offset]; +} + + +WRITE8_HANDLER( sega_usb_ram_w ) +{ + if (usb.in_latch & 0x80) + usb.program_ram[offset] = data; + else + LOG(("%04X:sega_usb_ram_w(%03X) = %02X while /LOAD disabled\n", activecpu_get_pc(), offset, data)); +} + + + +/************************************* + * + * I8035 port accesses + * + *************************************/ + +static READ8_HANDLER( usb_p1_r ) +{ + /* bits 0-6 are inputs and map to bits 0-6 of the input latch */ + if ((usb.in_latch & 0x7f) != 0) + LOG(("%03X: P1 read = %02X\n", activecpu_get_pc(), usb.in_latch & 0x7f)); + return usb.in_latch & 0x7f; +} + + +static WRITE8_HANDLER( usb_p1_w ) +{ + /* bit 7 maps to bit 0 on the output latch */ + usb.out_latch = (usb.out_latch & 0xfe) | (data >> 7); + LOG(("%03X: P1 write = %02X\n", activecpu_get_pc(), data)); +} + + +static WRITE8_HANDLER( usb_p2_w ) +{ + UINT8 old = usb.last_p2_value; + usb.last_p2_value = data; + + /* low 2 bits control the bank of work RAM we are addressing */ + usb.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) */ + usb.out_latch = ((data & 0x40) << 1) | (usb.out_latch & 0x7f); + if ((data & 0x40) == 0) + usb.in_latch = 0; + + /* bit 7 controls the reset on the upper counter at U33 */ + if ((old & 0x80) && !(data & 0x80)) + usb.t1_clock = 0; + + LOG(("%03X: P2 write -> bank=%d ready=%d clock=%d\n", activecpu_get_pc(), data & 3, (data >> 6) & 1, (data >> 7) & 1)); +} + + +static READ8_HANDLER( usb_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 (usb.t1_clock & usb.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; + } +} + + +static void usb_stream_update(void *param, stream_sample_t **inputs, stream_sample_t **outputs, int length) +{ + stream_sample_t *dest = outputs[0]; + + /* iterate over samples */ + while (length--) + { + 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 >= usb.noise_subcount; step -= usb.noise_subcount) + { + usb.noise_shift = (usb.noise_shift << 1) | (((usb.noise_shift >> 13) ^ (usb.noise_shift >> 16)) & 1); + usb.noise_state = (usb.noise_shift >> 16) & 1; + usb.noise_subcount = USB_2MHZ_CLOCK / MM5837_CLOCK; + } + usb.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 */ + usb.noise_filters[0].capval = 0.99765 * usb.noise_filters[0].capval + usb.noise_state * 0.0990460; + usb.noise_filters[1].capval = 0.96300 * usb.noise_filters[1].capval + usb.noise_state * 0.2965164; + usb.noise_filters[2].capval = 0.57000 * usb.noise_filters[2].capval + usb.noise_state * 1.0526913; + noiseval = usb.noise_filters[0].capval + usb.noise_filters[1].capval + usb.noise_filters[2].capval + usb.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(&usb.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 = &usb.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 = usb.gate_rc1_exp[g->chan[2].output]; + g->gate2.exponent = usb.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(&usb.final_filter, sample); + } +} + + +static void *usb_start(int clock, const struct CustomSound_interface *config) +{ + filter_state temp; + int tchan, tgroup; + + /* find the CPU we are associated with */ + usb.cpunum = mame_find_cpu_index(Machine, "usb"); + assert(usb.cpunum != (UINT8)-1); + + /* allocate work RAM */ + usb.work_ram = auto_malloc(0x400); + + /* create a sound stream */ + usb.stream = stream_create(0, 1, SAMPLE_RATE, NULL, usb_stream_update); + + /* initialize state */ + usb.noise_shift = 0x15555; + + for (tgroup = 0; tgroup < 3; tgroup++) + { + timer8253 *g = &usb.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); + usb.gate_rc1_exp[0] = temp.exponent; + configure_filter(&temp, 1e3, 0.01e-6); + usb.gate_rc1_exp[1] = temp.exponent; + configure_filter(&temp, 2 * 100e3, 0.01e-6); + usb.gate_rc2_exp[0] = temp.exponent; + configure_filter(&temp, 2 * 1e3, 0.01e-6); + usb.gate_rc2_exp[1] = temp.exponent; + + configure_filter(&usb.noise_filters[0], 2.7e3 + 2.7e3, 1.0e-6); + configure_filter(&usb.noise_filters[1], 2.7e3 + 1e3, 0.30e-6); + configure_filter(&usb.noise_filters[2], 2.7e3 + 270, 0.15e-6); + configure_filter(&usb.noise_filters[3], 2.7e3 + 0, 0.082e-6); + configure_filter(&usb.noise_filters[4], 33e3, 0.1e-6); + + configure_filter(&usb.final_filter, 100e3, 4.7e-6); + + /* register for save states */ + state_save_register_item("usb", 0, usb.in_latch); + state_save_register_item("usb", 0, usb.out_latch); + state_save_register_item("usb", 0, usb.last_p2_value); + state_save_register_item("usb", 0, usb.work_ram_bank); + state_save_register_item("usb", 0, usb.t1_clock); + + for (tgroup = 0; tgroup < 3; tgroup++) + { + timer8253 *group = &usb.timer_group[tgroup]; + for (tchan = 0; tchan < 3; tchan++) + { + timer8253_channel *channel = &group->chan[tchan]; + state_save_register_item("usb", tgroup * 3 + tchan, channel->holding); + state_save_register_item("usb", tgroup * 3 + tchan, channel->latchmode); + state_save_register_item("usb", tgroup * 3 + tchan, channel->latchtoggle); + state_save_register_item("usb", tgroup * 3 + tchan, channel->clockmode); + state_save_register_item("usb", tgroup * 3 + tchan, channel->bcdmode); + state_save_register_item("usb", tgroup * 3 + tchan, channel->output); + state_save_register_item("usb", tgroup * 3 + tchan, channel->lastgate); + state_save_register_item("usb", tgroup * 3 + tchan, channel->gate); + state_save_register_item("usb", tgroup * 3 + tchan, channel->subcount); + state_save_register_item("usb", tgroup * 3 + tchan, channel->count); + state_save_register_item("usb", tgroup * 3 + tchan, channel->remain); + } + state_save_register_item_array("usb", tgroup, group->env); + state_save_register_item("usb", tgroup, group->chan_filter[0].capval); + state_save_register_item("usb", tgroup, group->chan_filter[1].capval); + state_save_register_item("usb", tgroup, group->gate1.capval); + state_save_register_item("usb", tgroup, group->gate2.capval); + state_save_register_item("usb", tgroup, group->config); + } + + state_save_register_item_array("usb", 0, usb.timer_mode); + state_save_register_item("usb", 0, usb.noise_shift); + state_save_register_item("usb", 0, usb.noise_state); + state_save_register_item("usb", 0, usb.noise_subcount); + state_save_register_item("usb", 0, usb.final_filter.capval); + state_save_register_item("usb", 0, usb.noise_filters[0].capval); + state_save_register_item("usb", 0, usb.noise_filters[1].capval); + state_save_register_item("usb", 0, usb.noise_filters[2].capval); + state_save_register_item("usb", 0, usb.noise_filters[3].capval); + state_save_register_item("usb", 0, usb.noise_filters[4].capval); + + return usb.stream; +} + + + +/************************************* + * + * USB timer and envelope controls + * + *************************************/ + +static void timer_w(int which, UINT8 offset, UINT8 data) +{ + timer8253 *g = &usb.timer_group[which]; + timer8253_channel *ch; + int was_holding; + + stream_update(usb.stream); + + /* 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; + } +} + + +static void env_w(int which, UINT8 offset, UINT8 data) +{ + timer8253 *g = &usb.timer_group[which]; + + stream_update(usb.stream); + + if (offset < 3) + g->env[offset] = (double)data; + else + g->config = data & 1; +} + + + +/************************************* + * + * USB work RAM access + * + *************************************/ + +static READ8_HANDLER( usb_workram_r ) +{ + offset += 256 * usb.work_ram_bank; + return usb.work_ram[offset]; +} + + +static WRITE8_HANDLER( usb_workram_w ) +{ + offset += 256 * usb.work_ram_bank; + usb.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; + } +} + + + +/************************************* + * + * USB address maps + * + *************************************/ + +static ADDRESS_MAP_START( usb_map, ADDRESS_SPACE_PROGRAM, 8 ) + AM_RANGE(0x0000, 0x0fff) AM_RAM AM_BASE(&usb.program_ram) +ADDRESS_MAP_END + + +static ADDRESS_MAP_START( usb_map_rom, ADDRESS_SPACE_PROGRAM, 8 ) + AM_RANGE(0x0000, 0x0fff) AM_ROM +ADDRESS_MAP_END + + +static ADDRESS_MAP_START( usb_portmap, ADDRESS_SPACE_IO, 8 ) + AM_RANGE(0x00, 0xff) AM_READWRITE(usb_workram_r, usb_workram_w) + AM_RANGE(I8039_p1, I8039_p1) AM_READWRITE(usb_p1_r, usb_p1_w) + AM_RANGE(I8039_p2, I8039_p2) AM_WRITE(usb_p2_w) + AM_RANGE(I8039_t1, I8039_t1) AM_READ(usb_t1_r) +ADDRESS_MAP_END + + + +/************************************* + * + * USB sound definitions + * + *************************************/ + +static struct CustomSound_interface usb_custom_interface = +{ + usb_start +}; + + + +/************************************* + * + * USB machine drivers + * + *************************************/ + +MACHINE_DRIVER_START( sega_universal_sound_board ) + + /* CPU for the usb board */ + MDRV_CPU_ADD_TAG("usb", I8035, USB_MASTER_CLOCK/15) /* divide by 15 in CPU */ + MDRV_CPU_PROGRAM_MAP(usb_map, 0) + MDRV_CPU_IO_MAP(usb_portmap, 0) + + /* sound hardware */ + MDRV_SOUND_ADD(CUSTOM, 0) + MDRV_SOUND_CONFIG(usb_custom_interface) + MDRV_SOUND_ROUTE(ALL_OUTPUTS, "mono", 1.0) +MACHINE_DRIVER_END + + +MACHINE_DRIVER_START( sega_universal_sound_board_rom ) + MDRV_IMPORT_FROM( sega_universal_sound_board ) + + /* CPU for the usb board */ + MDRV_CPU_MODIFY("usb") + MDRV_CPU_PROGRAM_MAP(usb_map_rom, 0) +MACHINE_DRIVER_END |