/***************************************************************************
Konami 005289 - SCC sound as used in Bubblesystem
This file is pieced together by Bryan McPhail from a combination of
Namco Sound, Amuse by Cab, Nemesis schematics and whoever first
figured out SCC!
The 005289 is a 2 channel sound generator, each channel gets it's
waveform from a prom (4 bits wide).
(From Nemesis schematics)
Address lines A0-A4 of the prom run to the 005289, giving 32 bytes
per waveform. Address lines A5-A7 of the prom run to PA5-PA7 of
the AY8910 control port A, giving 8 different waveforms. PA0-PA3
of the AY8910 control volume.
The second channel is the same as above except port B is used.
The 005289 has no data bus, so data values written don't matter.
There are 4 unknown pins, LD1, LD2, TG1, TG2. Two of them look to be
the selector for changing frequency. The other two seem unused.
***************************************************************************/
#include "emu.h"
#include "k005289.h"
#define FREQBASEBITS 16
// device type definition
const device_type K005289 = &device_creator<k005289_device>;
//**************************************************************************
// LIVE DEVICE
//**************************************************************************
//-------------------------------------------------
// k005289_device - constructor
//-------------------------------------------------
k005289_device::k005289_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock)
: device_t(mconfig, K005289, "K005289", tag, owner, clock),
device_sound_interface(mconfig, *this),
m_sound_prom(NULL),
m_stream(NULL),
m_mclock(0),
m_rate(0),
m_mixer_table(NULL),
m_mixer_lookup(NULL),
m_mixer_buffer(NULL),
m_k005289_A_frequency(0),
m_k005289_B_frequency(0),
m_k005289_A_volume(0),
m_k005289_B_volume(0),
m_k005289_A_waveform(0),
m_k005289_B_waveform(0),
m_k005289_A_latch(0),
m_k005289_B_latch(0)
{
}
//-------------------------------------------------
// device_start - device-specific startup
//-------------------------------------------------
void k005289_device::device_start()
{
k005289_sound_channel *voice;
voice = m_channel_list;
/* get stream channels */
m_rate = clock()/16;
m_stream = stream_alloc(0, 1, m_rate);
m_mclock = clock();
/* allocate a pair of buffers to mix into - 1 second's worth should be more than enough */
m_mixer_buffer = auto_alloc_array(machine(), short, 2 * m_rate);
/* build the mixer table */
make_mixer_table(2);
m_sound_prom = m_region->base();
/* reset all the voices */
voice[0].frequency = 0;
voice[0].volume = 0;
voice[0].wave = &m_sound_prom[0];
voice[0].counter = 0;
voice[1].frequency = 0;
voice[1].volume = 0;
voice[1].wave = &m_sound_prom[0x100];
voice[1].counter = 0;
}
//-------------------------------------------------
// sound_stream_update - handle a stream update
//-------------------------------------------------
void k005289_device::sound_stream_update(sound_stream &stream, stream_sample_t **inputs, stream_sample_t **outputs, int samples)
{
k005289_sound_channel *voice=m_channel_list;
stream_sample_t *buffer = outputs[0];
short *mix;
int i,v,f;
/* zap the contents of the mixer buffer */
memset(m_mixer_buffer, 0, samples * sizeof(INT16));
v=voice[0].volume;
f=voice[0].frequency;
if (v && f)
{
const unsigned char *w = voice[0].wave;
int c = voice[0].counter;
mix = m_mixer_buffer;
/* add our contribution */
for (i = 0; i < samples; i++)
{
int offs;
c+=(long)((((float)m_mclock / (float)(f * 16))*(float)(1<<FREQBASEBITS)) / (float)(m_rate / 32));
offs = (c >> 16) & 0x1f;
*mix++ += ((w[offs] & 0x0f) - 8) * v;
}
/* update the counter for this voice */
voice[0].counter = c;
}
v=voice[1].volume;
f=voice[1].frequency;
if (v && f)
{
const unsigned char *w = voice[1].wave;
int c = voice[1].counter;
mix = m_mixer_buffer;
/* add our contribution */
for (i = 0; i < samples; i++)
{
int offs;
c+=(long)((((float)m_mclock / (float)(f * 16))*(float)(1<<FREQBASEBITS)) / (float)(m_rate / 32));
offs = (c >> 16) & 0x1f;
*mix++ += ((w[offs] & 0x0f) - 8) * v;
}
/* update the counter for this voice */
voice[1].counter = c;
}
/* mix it down */
mix = m_mixer_buffer;
for (i = 0; i < samples; i++)
*buffer++ = m_mixer_lookup[*mix++];
}
/********************************************************************************/
/* build a table to divide by the number of voices */
void k005289_device::make_mixer_table(int voices)
{
int count = voices * 128;
int i;
int gain = 16;
/* allocate memory */
m_mixer_table = auto_alloc_array(machine(), INT16, 256 * voices);
/* find the middle of the table */
m_mixer_lookup = m_mixer_table + (128 * voices);
/* fill in the table - 16 bit case */
for (i = 0; i < count; i++)
{
int val = i * gain * 16 / voices;
if (val > 32767) val = 32767;
m_mixer_lookup[ i] = val;
m_mixer_lookup[-i] = -val;
}
}
void k005289_device::k005289_recompute()
{
k005289_sound_channel *voice = m_channel_list;
m_stream->update(); /* update the streams */
voice[0].frequency = m_k005289_A_frequency;
voice[1].frequency = m_k005289_B_frequency;
voice[0].volume = m_k005289_A_volume;
voice[1].volume = m_k005289_B_volume;
voice[0].wave = &m_sound_prom[32 * m_k005289_A_waveform];
voice[1].wave = &m_sound_prom[32 * m_k005289_B_waveform + 0x100];
}
WRITE8_MEMBER( k005289_device::k005289_control_A_w )
{
m_k005289_A_volume=data&0xf;
m_k005289_A_waveform=data>>5;
k005289_recompute();
}
WRITE8_MEMBER( k005289_device::k005289_control_B_w )
{
m_k005289_B_volume=data&0xf;
m_k005289_B_waveform=data>>5;
k005289_recompute();
}
WRITE8_MEMBER( k005289_device::k005289_pitch_A_w )
{
m_k005289_A_latch = 0x1000 - offset;
}
WRITE8_MEMBER( k005289_device::k005289_pitch_B_w )
{
m_k005289_B_latch = 0x1000 - offset;
}
WRITE8_MEMBER( k005289_device::k005289_keylatch_A_w )
{
m_k005289_A_frequency = m_k005289_A_latch;
k005289_recompute();
}
WRITE8_MEMBER( k005289_device::k005289_keylatch_B_w )
{
m_k005289_B_frequency = m_k005289_B_latch;
k005289_recompute();
}