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oberheim/dmx.cpp: Added metronome and other audio improvements. (#13367)

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* Emulating metronome, including mixing with the rest of the voices.
* Emulating the RC HPFs for each voice and for the metronome.
* Using component values from electrongate.
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m1macrophage 2025-02-15 04:38:16 -08:00 committed by GitHub
parent 412b223084
commit 66822c511b
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1 changed files with 131 additions and 62 deletions
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src/mame/oberheim/dmx.cpp
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@ -44,10 +44,8 @@ PCBoards:
- 2 x cymbal cards: A single voice that occupies two card slots.
Known audio inaccuracies (reasons for MACHINE_IMPERFECT_SOUND):
- Closed and Accent hi-hat volume variations might be wrong. See comments in
HIHAT_CONFIG (to be researched soon).
- Uncertainty on component values for PERC2 (see comments in PERC_CONFIG).
- No metronome yet.
- Some uncertainty on component values for HIHAT and PERC2 (see comments in
HIHAT_CONFIG and PERC_CONFIG).
- Linear- instead of audio-taper faders.
- Envelope decay ignores diodes in capacitor discharge path. Given the quick
decay, and that the error is larger at low volumes, this might not be
@ -81,7 +79,9 @@ Usage notes:
#include "machine/timer.h"
#include "sound/dac76.h"
#include "sound/flt_biquad.h"
#include "sound/flt_rc.h"
#include "sound/mixer.h"
#include "sound/spkrdev.h"
#include "video/dl1416.h"
#include "speaker.h"
@ -95,6 +95,7 @@ Usage notes:
#define LOG_VOLUME (1U << 6)
#define LOG_SAMPLES (1U << 7)
#define LOG_SAMPLES_DECAY (1U << 8)
#define LOG_METRONOME (1U << 9)
#define VERBOSE (LOG_GENERAL)
//#define LOG_OUTPUT_FUNC osd_printf_info
@ -126,7 +127,7 @@ struct dmx_voice_card_config
// Contains 8 ROMs instead of 1. Used for Cymbal voice cards.
const bool multi_rom;
// Triggers control pitch variations (rather than volume variations).
// The triggers control pitch variations (rather than volume variations).
const bool pitch_control;
enum class decay_mode : s8 // Controlled by jumper Z on voice card.
@ -807,19 +808,19 @@ constexpr const dmx_voice_card_config SNARE_CONFIG =
.filter = FILTER_CONFIG_HIGH,
};
// Some component values in HIHAT_CONFIG might be wrong.
// The 1981 schematic shows 6.8uF for c3. electrongate.com reports 2.2uF. The
// service manual states that c3 can be changed, and offers a useful range of
// 2uF - 10uF.
// Similarly, resistor values in electrongate.com disagree with schematics.
// - electrongate.com: R12 = 6.8K, R17 not installed.
// - schematics: R12 = 1.5K, R17 = 15.
// Using the electrongate values below.
constexpr const dmx_voice_card_config HIHAT_CONFIG =
{
.c2 = CAP_U(0.0033),
.c3 = CAP_U(6.8),
.r12 = RES_K(1.5),
.r17 = RES_R(15),
.c3 = CAP_U(2.2),
.r12 = RES_K(6.8),
.r17 = RES_M(100), // Not connected. Using a huge resistor.
.split_rom = false,
.multi_rom = false,
.pitch_control = false,
@ -842,7 +843,7 @@ constexpr const dmx_voice_card_config TOM_CONFIG =
.filter = FILTER_CONFIG_LOW,
};
constexpr dmx_voice_card_config PERC_CONFIG(float c2)
constexpr dmx_voice_card_config PERC_CONFIG(float c2, bool filter_high)
{
// The schematic and electrongate.com agree on all components for PERC1,
// but disagree for PERC2:
@ -860,7 +861,7 @@ constexpr dmx_voice_card_config PERC_CONFIG(float c2)
.pitch_control = false,
.decay = dmx_voice_card_config::decay_mode::DISABLED,
.early_decay = dmx_voice_card_config::early_decay_mode::ENABLED_ON_TR1,
.filter = FILTER_CONFIG_HIGH,
.filter = filter_high ? FILTER_CONFIG_HIGH : FILTER_CONFIG_LOW,
};
}
@ -894,12 +895,15 @@ public:
VC_CYMBAL,
NUM_VOICE_CARDS
};
static constexpr const int METRONOME_INDEX = NUM_VOICE_CARDS;
dmx_state(const machine_config &mconfig, device_type type, const char *tag) ATTR_COLD
: driver_device(mconfig, type, tag)
, m_maincpu(*this, MAINCPU_TAG)
, m_digit_device(*this, "dl1414_%d", 0)
, m_digit_output(*this, "digit_%d", 0U)
, m_metronome(*this, "metronome_sound")
, m_metronome_out(*this, "METRONOME_OUT")
, m_metronome_timer(*this, "metronome_timer")
, m_buttons(*this, "buttons_%d", 0)
, m_faders(*this, "fader_p%d", 1)
@ -908,9 +912,8 @@ public:
, m_output_select(*this, "output_select")
, m_clk_in(*this, "clk_in")
, m_clk_out_tip(*this, "CLK_OUT_tip")
, m_metronome_mix(*this, "METRONOME_MIX")
, m_metronome(*this, "METRONOME")
, m_voices(*this, "voice_%d", 0)
, m_voice_rc(*this, "voice_rc_filter_%d", 0)
, m_left_mixer(*this, "left_mixer")
, m_right_mixer(*this, "right_mixer")
, m_left_speaker(*this, "lspeaker")
@ -924,7 +927,6 @@ public:
DECLARE_INPUT_CHANGED_MEMBER(clk_in_changed);
DECLARE_INPUT_CHANGED_MEMBER(selected_output_changed);
DECLARE_INPUT_CHANGED_MEMBER(voice_volume_changed);
DECLARE_INPUT_CHANGED_MEMBER(metronome_volume_changed);
DECLARE_INPUT_CHANGED_MEMBER(master_volume_changed);
DECLARE_INPUT_CHANGED_MEMBER(pitch_adj_changed);
@ -938,8 +940,10 @@ private:
void int_timer_enable_w(int state);
TIMER_DEVICE_CALLBACK_MEMBER(int_timer_tick);
void metronome_trigger_w(u8 data);
void update_metronome();
void metronome_mix_w(u8 data);
void metronome_level_w(int state);
void metronome_trigger_w(u8 data);
TIMER_DEVICE_CALLBACK_MEMBER(metronome_timer_tick);
void display_w(offs_t offset, u8 data);
@ -951,7 +955,7 @@ private:
template<int GROUP> void gen_trigger_w(u8 data);
void update_output();
void update_voice_volume(int voice);
void update_mix_level(int voice);
void memory_map(address_map &map) ATTR_COLD;
void io_map(address_map &map) ATTR_COLD;
@ -959,6 +963,8 @@ private:
required_device<z80_device> m_maincpu;
required_device_array<dl1414_device, 4> m_digit_device;
output_finder<16> m_digit_output;
required_device<speaker_sound_device> m_metronome;
output_finder<> m_metronome_out;
required_device<timer_device> m_metronome_timer;
required_ioport_array<6> m_buttons;
required_ioport_array<10> m_faders;
@ -967,10 +973,9 @@ private:
required_ioport m_output_select;
required_ioport m_clk_in;
output_finder<> m_clk_out_tip; // Tip conncetion of "CLK OUT" TRS jack.
output_finder<> m_metronome_mix;
output_finder<> m_metronome;
required_device_array<dmx_voice_card_device, 8> m_voices;
required_device_array<filter_rc_device, 9> m_voice_rc;
required_device<mixer_device> m_left_mixer;
required_device<mixer_device> m_right_mixer;
required_device<speaker_device> m_left_speaker;
@ -984,6 +989,11 @@ private:
u8 m_int_timer_out = 1;
u8 m_int_flipflop_clock = 0;
// Metronome state.
bool m_metronome_on = false;
bool m_metronome_mix = false;
bool m_metronome_level_high = false;
// The service manual states that the crystal is 4.912MHz, in the section
// that describes the clock circuitry. However, the parts list specifies
// this as a 4.9152 MHz crystal. The parts list value is likely the correct
@ -1002,18 +1012,26 @@ private:
HIHAT_CONFIG, // VC_HIHAT
TOM_CONFIG, // VC_SMALL_TOMS
TOM_CONFIG, // VC_LARGE_TOMS
PERC_CONFIG(CAP_U(0.0033)), // VC_PERC1
PERC_CONFIG(CAP_U(0.0047)), // VC_PERC2
PERC_CONFIG(CAP_U(0.0033), true), // VC_PERC1
PERC_CONFIG(CAP_U(0.0047), false), // VC_PERC2
CYMBAL_CONFIG, // VC_CYMBAL
};
// The loud click is a ~2.5V pulse, while the quiet one is a ~1.25V pulse.
// See update_metronome().
static constexpr double METRONOME_LEVELS[3] = { 0.0, 0.5, 1.0 };
// The mixer's inputs are the 8 voices and the metronome.
static constexpr const int NUM_MIXED_VOICES = NUM_VOICE_CARDS + 1;
// The left and right channel mixing resistors for each voice. The voice
// will be panned towards the side with lower resistance. Furthermore, these
// resistors control the relative volume of the voices, where lower
// resistance means louder.
// Each entry needs to appear in the index specified by voice_card_indices.
// Each entry needs to appear in the index specified by voice_card_indices,
// except for the metronome entry, which appears last.
// All resistors are located on the switchboard.
static constexpr const std::tuple<float, float> MIX_RESISTORS[NUM_VOICE_CARDS] =
static constexpr const std::tuple<float, float> MIX_RESISTORS[NUM_MIXED_VOICES] =
{
{ RES_K(10), RES_K(10) }, // R10, R9 - VC_BASS
{ RES_K(8.2), RES_K(20) }, // R12, R11 - VC_SNARE
@ -1023,11 +1041,13 @@ private:
{ RES_K(6.8), RES_K(100) }, // R22, R21 - VC_PERC1
{ RES_K(100), RES_K(6.8) }, // R24, R23 - VC_PERC2
{ RES_K(8.2), RES_K(20) }, // R20, R19 - VC_CYMBAL
{ RES_K(10), RES_K(10) }, // R26, R25 - METRONOME_INDEX
// ECO 304 values (see update_metronome()).
};
static constexpr const int VOICE_TO_FADER_MAP[NUM_VOICE_CARDS] =
static constexpr const int VOICE_TO_FADER_MAP[NUM_MIXED_VOICES] =
{
0, 1, 2, 3, 4, 6, 7, 5,
0, 1, 2, 3, 4, 6, 7, 5, 8
};
};
@ -1123,32 +1143,65 @@ TIMER_DEVICE_CALLBACK_MEMBER(dmx_state::int_timer_tick)
}
}
void dmx_state::metronome_trigger_w(u8 /*data*/)
void dmx_state::update_metronome()
{
// Writing to this port clocks U33A (D-flipflop). R62 and C32 form an RC
// network that resets the flipflop after ~1ms. This becomes a 1ms, 10-12V
// pulse (via Q8, R55, R54) on the "metronome out" connection.
// (component designations refer to the Processor Board)
m_metronome_timer->adjust(attotime::from_msec(1));
m_metronome = 1;
// The metronome "click" is a 1ms pulse. The metronome is active during
// playback and recording, and the pulses appear on the "metronome out"
// connection. The metronome can also be mixed with the rest of the voices,
// but this only happens during recording, not playback. The loudness of
// the "click" can be controlled by the firmware (2 distinct levels).
// The metronome circuit is also used to generate "beep" tones.
// The emulated circuitry is that of Engineering Change Order 304 (ECO 304,
// January 1982), which improved the metronome.
m_metronome_out = m_metronome_on ? 1 : 0; // ~10 Volt pulse on "metronome out".
int level = 0;
if (m_metronome_on && m_metronome_mix)
level = m_metronome_level_high ? 2 : 1;
m_metronome->level_w(level);
LOGMASKED(LOG_METRONOME, "Metronome update - on:%d, mix:%d, level:%d\n",
m_metronome_on, m_metronome_mix, level);
}
void dmx_state::metronome_mix_w(u8 data)
{
// D0 connected to D of U35 74LS74 (D-flipflop), which is clocked by
// CLICK* from the address decoder (U7, 74LS42).
// CLICK* from the address decoder (U7, 74LS42), acting as a 1-bit latch.
const bool new_value = BIT(data, 0);
if (m_metronome_mix == new_value)
return;
m_metronome_mix = new_value;
update_metronome();
}
// The service manual states that this bit enables mixing the metronome into
// the main mix, and that the LVI signal controls the volume. But that seems
// to describe how the firmware uses these. Looking at the schematic, it
// seems that both this signal and LVI would enable mixing on their own, and
// setting both to 1 would increase the volume.
m_metronome_mix = BIT(data, 0);
void dmx_state::metronome_level_w(int state)
{
// LV1 signal. D3 of U20 (74C174 latch, processor board).
const bool new_value = state;
if (m_metronome_level_high == new_value)
return;
m_metronome_level_high = new_value;
update_metronome();
}
void dmx_state::metronome_trigger_w(u8 /*data*/)
{
// Writing to this port clocks U33A (D-flipflop). R62 and C32 form an RC
// network that resets the flipflop after ~1ms. This becomes a pulse (via
// Q8, R55, R54) on the "metronome out" connection, and in some cases also
// mixed with the other voices (see update_metronome()).
m_metronome_timer->adjust(attotime::from_msec(1));
m_metronome_on = true;
update_metronome();
}
TIMER_DEVICE_CALLBACK_MEMBER(dmx_state::metronome_timer_tick)
{
m_metronome = 0;
m_metronome_on = false;
update_metronome();
}
void dmx_state::display_w(offs_t offset, u8 data)
@ -1257,17 +1310,21 @@ void dmx_state::update_output()
LOGMASKED(LOG_FADERS, "Output changed to: %d\n", m_output_select->read());
}
void dmx_state::update_voice_volume(int voice)
void dmx_state::update_mix_level(int voice)
{
// Computes the gain of a voice for the left and right channels, taking
// into account the fader position and the loading from the mixing
// resistors. Each voice has a hardcoded pan and relative mixing ratio based
// on the resistors in MIX_RESISTORS.
assert(voice >= 0 && voice < NUM_VOICE_CARDS);
// Also reconfigures the voice's output RC filter (high-pass), since its `R`
// changes when the volume fader moves. This won't be audible, since the
// cutoff frequency is mostly <10 HZ, except for low volumes.
assert(voice >= 0 && voice < NUM_MIXED_VOICES);
static constexpr const float P_MAX = RES_K(10); // Volume potentiometer.
static constexpr const float VC_R21 = RES_R(4.7); // R21 on voice cards.
static constexpr const float VC_C10 = CAP_U(33); // C10 on voice cards.
static constexpr const float PB_C24 = CAP_U(6.8); // C24 on processor board.
// Feedback resistors on the left and right summing op-amps (U1B, U1C).
static constexpr const float R_FEEDBACK_LEFT = RES_K(4.7); // R30.
@ -1279,16 +1336,20 @@ void dmx_state::update_voice_volume(int voice)
const float r_mix_left = std::get<0>(MIX_RESISTORS[voice]);
const float r_mix_right = std::get<1>(MIX_RESISTORS[voice]);
const float r_gnd = RES_3_PARALLEL(r_pot_bottom, r_mix_left, r_mix_right);
const float r_top_extra = (voice == METRONOME_INDEX) ? 0 : VC_R21;
const float v_pot = RES_VOLTAGE_DIVIDER(r_pot_top + r_top_extra, r_gnd);
const float v_pot = RES_VOLTAGE_DIVIDER(r_pot_top + VC_R21, r_gnd);
const float gain_left = v_pot * R_FEEDBACK_LEFT / r_mix_left;
const float gain_right = v_pot * R_FEEDBACK_RIGHT / r_mix_right;
// -v_pot because the summing opamp mixer is inverting.
const float gain_left = -v_pot * R_FEEDBACK_LEFT / r_mix_left;
const float gain_right = -v_pot * R_FEEDBACK_RIGHT / r_mix_right;
const float rc_c = (voice == METRONOME_INDEX) ? PB_C24 : VC_C10;
m_voice_rc[voice]->filter_rc_set_RC(filter_rc_device::HIGHPASS, r_gnd, 0, 0, rc_c);
m_left_mixer->set_input_gain(voice, gain_left);
m_right_mixer->set_input_gain(voice, gain_right);
LOGMASKED(LOG_FADERS, "Voice %d volume changed to: %d (gain L:%f, R:%f)\n",
voice, pot_percent, gain_left, gain_right);
LOGMASKED(LOG_FADERS, "Voice %d volume changed to: %d (gain L:%f, R:%f), HPF cutoff: %.02f Hz\n",
voice, pot_percent, gain_left, gain_right, 1.0F / (2 * float(M_PI) * r_gnd * rc_c));
}
void dmx_state::memory_map(address_map &map)
@ -1326,8 +1387,7 @@ void dmx_state::io_map(address_map &map)
void dmx_state::machine_start()
{
m_clk_out_tip.resolve();
m_metronome_mix.resolve();
m_metronome.resolve();
m_metronome_out.resolve();
m_digit_output.resolve();
save_item(NAME(m_int_timer_preset));
@ -1335,13 +1395,17 @@ void dmx_state::machine_start()
save_item(NAME(m_int_timer_value));
save_item(NAME(m_int_timer_out));
save_item(NAME(m_int_flipflop_clock));
save_item(NAME(m_metronome_on));
save_item(NAME(m_metronome_mix));
save_item(NAME(m_metronome_level_high));
}
void dmx_state::machine_reset()
{
update_output();
for (int i = 0; i < NUM_VOICE_CARDS; ++i)
update_voice_volume(i);
for (int i = 0; i < NUM_MIXED_VOICES; ++i)
update_mix_level(i);
}
void dmx_state::dmx(machine_config &config)
@ -1375,7 +1439,7 @@ void dmx_state::dmx(machine_config &config)
cas_latch.bit_handler<2>().set(FUNC(dmx_state::int_timer_enable_w));
// Bit 3 is an open-collector connection to the Ring of the "CLK OUT" TRS jack.
cas_latch.bit_handler<3>().set_output("CLK_OUT_ring").invert();
cas_latch.bit_handler<4>().set_output("LVI");
cas_latch.bit_handler<4>().set(FUNC(dmx_state::metronome_level_w)); // LV1.
// Bit 5 not connected.
MIXER(config, m_left_mixer);
@ -1383,10 +1447,21 @@ void dmx_state::dmx(machine_config &config)
for (int i = 0; i < NUM_VOICE_CARDS; ++i)
{
DMX_VOICE_CARD(config, m_voices[i], VOICE_CONFIGS[i], &m_samples[i]);
m_voices[i]->add_route(ALL_OUTPUTS, m_left_mixer, 1.0);
m_voices[i]->add_route(ALL_OUTPUTS, m_right_mixer, 1.0);
FILTER_RC(config, m_voice_rc[i]);
// The RC filters are initialized in machine_reset() (specifically:
// update_mix_level()).
m_voices[i]->add_route(ALL_OUTPUTS, m_voice_rc[i], 1.0);
m_voice_rc[i]->add_route(ALL_OUTPUTS, m_left_mixer, 1.0);
m_voice_rc[i]->add_route(ALL_OUTPUTS, m_right_mixer, 1.0);
}
SPEAKER_SOUND(config, m_metronome);
FILTER_RC(config, m_voice_rc[METRONOME_INDEX]);
m_metronome->set_levels(3, METRONOME_LEVELS);
m_metronome->add_route(ALL_OUTPUTS, m_voice_rc[METRONOME_INDEX], 1.0);
m_voice_rc[METRONOME_INDEX]->add_route(ALL_OUTPUTS, m_left_mixer, 1.0);
m_voice_rc[METRONOME_INDEX]->add_route(ALL_OUTPUTS, m_right_mixer, 1.0);
// Passive mixer using 1K resistors (R33 and R34).
mixer_device &mono_mixer = MIXER(config, "mono_mixer");
m_left_mixer->add_route(ALL_OUTPUTS, mono_mixer, 0.5);
@ -1416,13 +1491,7 @@ DECLARE_INPUT_CHANGED_MEMBER(dmx_state::selected_output_changed)
DECLARE_INPUT_CHANGED_MEMBER(dmx_state::voice_volume_changed)
{
update_voice_volume(param);
}
DECLARE_INPUT_CHANGED_MEMBER(dmx_state::metronome_volume_changed)
{
// TODO: Implement once metronome is emulated.
LOGMASKED(LOG_FADERS, "Metronome volume changed: %d\n", newval);
update_mix_level(param);
}
DECLARE_INPUT_CHANGED_MEMBER(dmx_state::master_volume_changed)
@ -1565,7 +1634,7 @@ INPUT_PORTS_START(dmx)
PORT_START("fader_p9")
PORT_ADJUSTER(100, "MET volume")
PORT_CHANGED_MEMBER(DEVICE_SELF, FUNC(dmx_state::metronome_volume_changed), 0)
PORT_CHANGED_MEMBER(DEVICE_SELF, FUNC(dmx_state::voice_volume_changed), dmx_state::METRONOME_INDEX)
PORT_START("fader_p10")
PORT_ADJUSTER(100, "VOLUME")