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|
// license:BSD-3-Clause
// copyright-holders:Aaron Giles
/***************************************************************************
Bally/Sente 6VB audio board emulation
This serial audio board appears to be based on the Sequential Circuits
Six-Trak synthesizer.
The later revision of this board replaces the 8253-5 PIT and much
associated logic with a ST1001 custom gate array.
****************************************************************************
Memory map
****************************************************************************
========================================================================
Z80 CPU
========================================================================
0000-1FFF R xxxxxxxx Program ROM
2000-3FFF R/W xxxxxxxx Option RAM/ROM (assumed to be RAM for now)
4000-5FFF R/W xxxxxxxx Program RAM
6000-6001 W xxxxxxxx 6850 UART output (to main board)
E000-E001 R xxxxxxxx 6850 UART input (from main board)
========================================================================
0000-0003 R/W xxxxxxxx 8253 counter chip I/O
0008 R ------xx Counter state
R ------x- State of counter #0 OUT signal (active high)
R -------x State of flip-flop feeding counter #0 (active low)
0008 W --xxxxxx Counter control
W --x----- NMI enable (1=enabled, 0=disabled/clear)
W ---x---- CLEAR on flip-flop feeding counter #0 (active low)
W ----x--- Input of flip-flop feeding counter #0
W -----x-- PRESET on flip-flop feeding counter #0 (active low)
W ------x- GATE signal for counter #0 (active high)
W -------x Audio enable
000A W --xxxxxx DAC data latch (upper 6 bits)
000B W xxxxxx-- DAC data latch (lower 6 bits)
000C W -----xxx CEM3394 register select
000E W --xxxxxx CEM3394 chip enable (active high)
W --x----- CEM3394 chip 0 enable
W ---x---- CEM3394 chip 1 enable
W ----x--- CEM3394 chip 2 enable
W -----x-- CEM3394 chip 3 enable
W ------x- CEM3394 chip 4 enable
W -------x CEM3394 chip 5 enable
========================================================================
Interrupts:
INT generated by counter #2 OUT signal on 8253
NMI generated by 6850 UART
========================================================================
***************************************************************************/
#include "emu.h"
#include "audio/sente6vb.h"
#include "cpu/z80/z80.h"
#include "machine/clock.h"
#include "speaker.h"
#define LOG_CEM_WRITES 0
DEFINE_DEVICE_TYPE(SENTE6VB, sente6vb_device, "sente6vb", "Bally Sente 6VB Audio Board")
/*************************************
*
* Sound CPU memory handlers
*
*************************************/
void sente6vb_device::mem_map(address_map &map)
{
map(0x0000, 0x1fff).rom().region("audiocpu", 0);
map(0x2000, 0x5fff).ram();
map(0x6000, 0x6001).mirror(0x1ffe).w(m_uart, FUNC(acia6850_device::write));
map(0xe000, 0xe001).mirror(0x1ffe).r(m_uart, FUNC(acia6850_device::read));
}
void sente6vb_device::io_map(address_map &map)
{
map.global_mask(0xff);
map(0x00, 0x03).rw(m_pit, FUNC(pit8253_device::read), FUNC(pit8253_device::write));
map(0x08, 0x0f).r(FUNC(sente6vb_device::counter_state_r));
map(0x08, 0x09).w(FUNC(sente6vb_device::counter_control_w));
map(0x0a, 0x0b).w(FUNC(sente6vb_device::dac_data_w));
map(0x0c, 0x0d).w(FUNC(sente6vb_device::register_addr_w));
map(0x0e, 0x0f).w(FUNC(sente6vb_device::chip_select_w));
}
/*************************************
*
* Device configuration
*
*************************************/
void sente6vb_device::device_add_mconfig(machine_config &config)
{
Z80(config, m_audiocpu, 8_MHz_XTAL / 2);
m_audiocpu->set_addrmap(AS_PROGRAM, &sente6vb_device::mem_map);
m_audiocpu->set_addrmap(AS_IO, &sente6vb_device::io_map);
ACIA6850(config, m_uart, 0);
m_uart->txd_handler().set([this] (int state) { m_send_cb(state); });
m_uart->irq_handler().set([this] (int state) { m_uint = bool(state); });
clock_device &uartclock(CLOCK(config, "uartclock", 8_MHz_XTAL / 16)); // 500 kHz
uartclock.signal_handler().set(FUNC(sente6vb_device::uart_clock_w));
uartclock.signal_handler().append(m_uart, FUNC(acia6850_device::write_txc));
uartclock.signal_handler().append(m_uart, FUNC(acia6850_device::write_rxc));
TIMER(config, m_counter_0_timer, 0).configure_generic(FUNC(sente6vb_device::clock_counter_0_ff));
PIT8253(config, m_pit, 0);
m_pit->out_handler<0>().set(FUNC(sente6vb_device::counter_0_set_out));
m_pit->out_handler<2>().set_inputline(m_audiocpu, INPUT_LINE_IRQ0);
m_pit->set_clk<1>(8_MHz_XTAL / 4);
m_pit->set_clk<2>(8_MHz_XTAL / 4);
SPEAKER(config, "mono").front_center();
for (auto &cem_device : m_cem_device)
{
CEM3394(config, cem_device, 0);
cem_device->set_vco_zero_freq(431.894);
cem_device->set_filter_zero_freq(1300.0);
cem_device->add_route(ALL_OUTPUTS, "mono", 0.90);
}
m_cem_device[0]->set_ext_input_callback(FUNC(sente6vb_device::noise_gen_0));
m_cem_device[1]->set_ext_input_callback(FUNC(sente6vb_device::noise_gen_1));
m_cem_device[2]->set_ext_input_callback(FUNC(sente6vb_device::noise_gen_2));
m_cem_device[3]->set_ext_input_callback(FUNC(sente6vb_device::noise_gen_3));
m_cem_device[4]->set_ext_input_callback(FUNC(sente6vb_device::noise_gen_4));
m_cem_device[5]->set_ext_input_callback(FUNC(sente6vb_device::noise_gen_5));
}
/*************************************
*
* ROM definition
*
*************************************/
ROM_START( sente6vb )
ROM_REGION( 0x2000, "audiocpu", 0 )
ROM_LOAD( "8002-10 9-25-84.5", 0x0000, 0x2000, CRC(4dd0a525) SHA1(f0c447adc5b67917851a9df978df851247e75c43) )
ROM_END
const tiny_rom_entry *sente6vb_device::device_rom_region() const
{
return ROM_NAME(sente6vb);
}
/*************************************
*
* Device initialization
*
*************************************/
sente6vb_device::sente6vb_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
: device_t(mconfig, SENTE6VB, tag, owner, clock)
, m_pit(*this, "pit")
, m_counter_0_timer(*this, "8253_0_timer")
, m_cem_device(*this, "cem%u", 1U)
, m_audiocpu(*this, "audiocpu")
, m_uart(*this, "uart")
, m_send_cb(*this)
, m_clock_out_cb(*this)
{
}
void sente6vb_device::device_start()
{
// create the polynomial tables
poly17_init();
m_send_cb.resolve_safe();
m_clock_out_cb.resolve_safe();
m_uart->write_cts(0);
m_uart->write_dcd(0);
save_item(NAME(m_counter_control));
save_item(NAME(m_counter_0_ff));
save_item(NAME(m_counter_0_out));
save_item(NAME(m_counter_0_timer_active));
save_item(NAME(m_dac_value));
save_item(NAME(m_dac_register));
save_item(NAME(m_chip_select));
save_item(NAME(m_uint));
save_item(NAME(m_noise_position));
}
void sente6vb_device::device_reset()
{
// reset the manual counter 0 clock
m_counter_control = 0x00;
m_counter_0_ff = false;
m_counter_0_out = false;
m_counter_0_timer_active = false;
m_audiocpu->set_input_line(INPUT_LINE_NMI, CLEAR_LINE);
// reset the CEM3394 I/O states
m_dac_value = 0;
m_dac_register = 0;
m_chip_select = 0x3f;
// reset the noise generator
memset(m_noise_position, 0, sizeof(m_noise_position));
}
/*************************************
*
* MM5837 noise generator
*
* NOTE: this is stolen straight from
* POKEY.c
*
*************************************/
void sente6vb_device::poly17_init()
{
uint32_t i, x = 0;
uint8_t *p;
// allocate memory
p = m_poly17;
// generate the polynomial
for (i = 0; i < POLY17_SIZE; i++)
{
// store new values
*p++ = x & 1;
// calculate next bit
x = ((x << POLY17_SHL) + (x >> POLY17_SHR) + POLY17_ADD) & POLY17_SIZE;
}
}
inline void sente6vb_device::noise_gen_chip(int chip, int count, short *buffer)
{
// noise generator runs at 100kHz
uint32_t step = (100000 << 14) / cem3394_device::SAMPLE_RATE;
uint32_t noise_counter = m_noise_position[chip];
while (count--)
{
*buffer++ = m_poly17[(noise_counter >> 14) & POLY17_SIZE] << 12;
noise_counter += step;
}
// remember the noise position
m_noise_position[chip] = noise_counter;
}
CEM3394_EXT_INPUT(sente6vb_device::noise_gen_0) { noise_gen_chip(0, count, buffer); }
CEM3394_EXT_INPUT(sente6vb_device::noise_gen_1) { noise_gen_chip(1, count, buffer); }
CEM3394_EXT_INPUT(sente6vb_device::noise_gen_2) { noise_gen_chip(2, count, buffer); }
CEM3394_EXT_INPUT(sente6vb_device::noise_gen_3) { noise_gen_chip(3, count, buffer); }
CEM3394_EXT_INPUT(sente6vb_device::noise_gen_4) { noise_gen_chip(4, count, buffer); }
CEM3394_EXT_INPUT(sente6vb_device::noise_gen_5) { noise_gen_chip(5, count, buffer); }
/*************************************
*
* 6850 UART communications
*
*************************************/
WRITE_LINE_MEMBER(sente6vb_device::rec_w)
{
m_uart->write_rxd(state);
}
WRITE_LINE_MEMBER(sente6vb_device::uart_clock_w)
{
if (state && BIT(m_counter_control, 5))
m_audiocpu->set_input_line(INPUT_LINE_NMI, m_uint ? ASSERT_LINE : CLEAR_LINE);
m_clock_out_cb(!state);
}
/*************************************
*
* Sound CPU counter 0 emulation
*
*************************************/
WRITE_LINE_MEMBER(sente6vb_device::counter_0_set_out)
{
// OUT on counter 0 is hooked to the GATE line on counter 1 through an inverter
m_pit->write_gate1(!state);
// remember the out state
m_counter_0_out = state;
}
WRITE_LINE_MEMBER(sente6vb_device::set_counter_0_ff)
{
// the flip/flop output is inverted, so if we went high to low, that's a clock
m_pit->write_clk0(!state);
// remember the new state
m_counter_0_ff = state;
}
TIMER_DEVICE_CALLBACK_MEMBER(sente6vb_device::clock_counter_0_ff)
{
// clock the D value through the flip-flop
set_counter_0_ff(BIT(m_counter_control, 3));
}
void sente6vb_device::update_counter_0_timer()
{
double maxfreq = 0.0;
int i;
// if there's already a timer, remove it
if (m_counter_0_timer_active)
m_counter_0_timer->reset();
m_counter_0_timer_active = false;
// find the counter with the maximum frequency
// this is used to calibrate the timers at startup
for (i = 0; i < 6; i++)
if (m_cem_device[i]->get_parameter(cem3394_device::FINAL_GAIN) < 10.0)
{
double tempfreq;
// if the filter resonance is high, then they're calibrating the filter frequency
if (m_cem_device[i]->get_parameter(cem3394_device::FILTER_RESONANCE) > 0.9)
tempfreq = m_cem_device[i]->get_parameter(cem3394_device::FILTER_FREQENCY);
// otherwise, they're calibrating the VCO frequency
else
tempfreq = m_cem_device[i]->get_parameter(cem3394_device::VCO_FREQUENCY);
if (tempfreq > maxfreq) maxfreq = tempfreq;
}
// reprime the timer
if (maxfreq > 0.0)
{
m_counter_0_timer_active = true;
m_counter_0_timer->adjust(attotime::from_hz(maxfreq), 0, attotime::from_hz(maxfreq));
}
}
/*************************************
*
* Sound CPU counter handlers
*
*************************************/
READ8_MEMBER(sente6vb_device::counter_state_r)
{
// bit D0 is the inverse of the flip-flop state
int result = !m_counter_0_ff;
// bit D1 is the OUT value from counter 0
if (m_counter_0_out) result |= 0x02;
return result;
}
WRITE8_MEMBER(sente6vb_device::counter_control_w)
{
uint8_t diff_counter_control = m_counter_control ^ data;
// set the new global value
m_counter_control = data;
// bit D0 enables/disables audio
if (BIT(diff_counter_control, 0))
{
for (auto & elem : m_cem_device)
elem->set_output_gain(0, BIT(data, 0) ? 1.0 : 0);
}
// bit D1 is hooked to counter 0's gate
if (BIT(diff_counter_control, 1))
{
// if we gate on, start a pulsing timer to clock it
if (BIT(data, 1) && !m_counter_0_timer_active)
{
update_counter_0_timer();
}
// if we gate off, remove the timer
else if (!BIT(data, 1) && m_counter_0_timer_active)
{
m_counter_0_timer->reset();
m_counter_0_timer_active = false;
}
}
// set the actual gate
m_pit->write_gate0(BIT(data, 1));
// bits D2 and D4 control the clear/reset flags on the flip-flop that feeds counter 0
if (!BIT(data, 4))
set_counter_0_ff(0);
else if (!BIT(data, 2))
set_counter_0_ff(1);
// bit 5 clears the NMI interrupt
if (BIT(diff_counter_control, 5) && !BIT(data, 5))
m_audiocpu->set_input_line(INPUT_LINE_NMI, CLEAR_LINE);
}
/*************************************
*
* CEM3394 Interfaces
*
*************************************/
WRITE8_MEMBER(sente6vb_device::chip_select_w)
{
static constexpr uint8_t register_map[8] =
{
cem3394_device::VCO_FREQUENCY,
cem3394_device::FINAL_GAIN,
cem3394_device::FILTER_RESONANCE,
cem3394_device::FILTER_FREQENCY,
cem3394_device::MIXER_BALANCE,
cem3394_device::MODULATION_AMOUNT,
cem3394_device::PULSE_WIDTH,
cem3394_device::WAVE_SELECT
};
double voltage = (double)m_dac_value * (8.0 / 4096.0) - 4.0;
int diffchip = data ^ m_chip_select, i;
int reg = register_map[m_dac_register];
// remember the new select value
m_chip_select = data;
// check all six chip enables
for (i = 0; i < 6; i++)
if ((diffchip & (1 << i)) && (data & (1 << i)))
{
#if LOG_CEM_WRITES
double temp = 0;
// remember the previous value
temp =
#endif
m_cem_device[i]->get_parameter(reg);
// set the voltage
m_cem_device[i]->set_voltage(reg, voltage);
// only log changes
#if LOG_CEM_WRITES
if (temp != m_cem_device[i]->get_parameter(reg))
{
static const char *const names[] =
{
"VCO_FREQUENCY",
"FINAL_GAIN",
"FILTER_RESONANCE",
"FILTER_FREQENCY",
"MIXER_BALANCE",
"MODULATION_AMOUNT",
"PULSE_WIDTH",
"WAVE_SELECT"
};
logerror("s%04X: CEM#%d:%s=%f\n", m_audiocpu->pcbase(), i, names[m_dac_register], voltage);
}
#endif
}
// if a timer for counter 0 is running, recompute
if (m_counter_0_timer_active)
update_counter_0_timer();
}
WRITE8_MEMBER(sente6vb_device::dac_data_w)
{
// LSB or MSB?
if (offset & 1)
m_dac_value = (m_dac_value & 0xfc0) | ((data >> 2) & 0x03f);
else
m_dac_value = (m_dac_value & 0x03f) | ((data << 6) & 0xfc0);
// if there are open channels, force the values in
if ((m_chip_select & 0x3f) != 0x3f)
{
uint8_t temp = m_chip_select;
chip_select_w(space, 0, 0x3f);
chip_select_w(space, 0, temp);
}
}
WRITE8_MEMBER(sente6vb_device::register_addr_w)
{
m_dac_register = data & 7;
}
|