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// license:BSD-3-Clause
// copyright-holders:Bryan McPhail
/*******************************************************************************
Konami 051649 - SCC1 sound as used in Haunted Castle, City Bomber
This file is pieced together by Bryan McPhail from a combination of
Namco Sound, Amuse by Cab, Haunted Castle schematics and whoever first
figured out SCC!
The 051649 is a 5 channel sound generator, each channel gets its
waveform from RAM (32 bytes per waveform, 8 bit signed data).
This sound chip is the same as the sound chip in some Konami
megaROM cartridges for the MSX. This device only emulates the
sound portion, not the memory mapper.
052539 is more or less equivalent to this chip except channel 5
does not share waveram with channel 4.
References:
- http://bifi.msxnet.org/msxnet/tech/scc.html
- http://bifi.msxnet.org/msxnet/tech/soundcartridge
TODO:
- make 052539 a subdevice
- bus conflicts on 051649 (not 052539). When the CPU accesses waveform RAM
and the SCC is reading it at the same time, it can cause audible spikes.
A similar thing happens internally when the shared ch4/ch5 do a read at
the same time.
- test register bits 0-4, not used in any software
*******************************************************************************/
#include "emu.h"
#include "k051649.h"
#include <algorithm>
void k051649_device::scc_map(address_map &map)
{
map(0x00, 0x7f).rw(FUNC(k051649_device::k051649_waveform_r), FUNC(k051649_device::k051649_waveform_w));
map(0x80, 0x89).mirror(0x10).w(FUNC(k051649_device::k051649_frequency_w));
map(0x8a, 0x8e).mirror(0x10).w(FUNC(k051649_device::k051649_volume_w));
map(0x8f, 0x8f).mirror(0x10).w(FUNC(k051649_device::k051649_keyonoff_w));
map(0xe0, 0xe0).mirror(0x1f).rw(FUNC(k051649_device::k051649_test_r), FUNC(k051649_device::k051649_test_w));
}
// device type definition
DEFINE_DEVICE_TYPE(K051649, k051649_device, "k051649", "K051649 SCC1")
//******************************************************************************
// LIVE DEVICE
//******************************************************************************
//-------------------------------------------------
// k051649_device - constructor
//-------------------------------------------------
k051649_device::k051649_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock)
: device_t(mconfig, K051649, tag, owner, clock)
, device_sound_interface(mconfig, *this)
, m_stream(nullptr)
, m_test(0)
{
}
//-------------------------------------------------
// device_start - device-specific startup
//-------------------------------------------------
void k051649_device::device_start()
{
// get stream channels
m_stream = stream_alloc(0, 1, clock());
// save states
save_item(STRUCT_MEMBER(m_channel_list, counter));
save_item(STRUCT_MEMBER(m_channel_list, clock));
save_item(STRUCT_MEMBER(m_channel_list, frequency));
save_item(STRUCT_MEMBER(m_channel_list, volume));
save_item(STRUCT_MEMBER(m_channel_list, sample));
save_item(STRUCT_MEMBER(m_channel_list, key));
save_item(STRUCT_MEMBER(m_channel_list, waveram));
save_item(NAME(m_test));
}
//-------------------------------------------------
// device_reset - device-specific reset
//-------------------------------------------------
void k051649_device::device_reset()
{
// reset all the voices
for (sound_channel &voice : m_channel_list)
{
voice.frequency = 0;
voice.volume = 0xf;
voice.counter = 0;
voice.clock = 0;
voice.key = false;
}
// other parameters
m_test = 0;
}
//-------------------------------------------------
// device_post_load - device-specific post-load
//-------------------------------------------------
void k051649_device::device_post_load()
{
device_clock_changed();
}
//-------------------------------------------------
// device_clock_changed - called if the clock
// changes
//-------------------------------------------------
void k051649_device::device_clock_changed()
{
m_stream->set_sample_rate(clock());
}
//-------------------------------------------------
// sound_stream_update - handle a stream update
//-------------------------------------------------
void k051649_device::sound_stream_update(sound_stream &stream)
{
for (int i = 0; i < stream.samples(); i++)
{
for (sound_channel &voice : m_channel_list)
{
// channel is halted for freq < 9
if (voice.frequency > 8)
{
if (++voice.clock > voice.frequency)
{
voice.counter = (voice.counter + 1) & 0x1f;
voice.clock = 0;
}
if (voice.clock == 0)
{
voice.sample = (voice.key ? voice.waveram[voice.counter] : 0) * voice.volume;
}
}
// scale to 11 bit digital output on chip
stream.add_int(0, i, voice.sample >> 4, 1024);
}
}
}
/******************************************************************************/
void k051649_device::k051649_waveform_w(offs_t offset, u8 data)
{
// waveram is read-only?
if (m_test & 0x40 || (m_test & 0x80 && offset >= 0x60))
return;
m_stream->update();
if (offset >= 0x60)
{
// channel 5 shares waveram with channel 4
m_channel_list[3].waveram[offset & 0x1f] = data;
m_channel_list[4].waveram[offset & 0x1f] = data;
}
else
m_channel_list[offset >> 5].waveram[offset & 0x1f] = data;
}
u8 k051649_device::k051649_waveform_r(offs_t offset)
{
u8 counter = 0;
// test register bits 6/7 expose the internal counter
if (m_test & 0xc0)
{
m_stream->update();
if (offset >= 0x60 && (m_test & 0xc0) != 0xc0)
counter = m_channel_list[3 + (m_test >> 6 & 1)].counter;
else if (m_test & 0x40)
counter = m_channel_list[offset >> 5].counter;
}
return m_channel_list[offset >> 5].waveram[(offset + counter) & 0x1f];
}
void k051649_device::k052539_waveform_w(offs_t offset, u8 data)
{
// waveram is read-only?
if (m_test & 0x40)
return;
m_stream->update();
m_channel_list[offset >> 5].waveram[offset & 0x1f] = data;
}
u8 k051649_device::k052539_waveform_r(offs_t offset)
{
u8 counter = 0;
// test register bit 6 exposes the internal counter
if (m_test & 0x40)
{
m_stream->update();
counter = m_channel_list[offset >> 5].counter;
}
return m_channel_list[offset >> 5].waveram[(offset + counter) & 0x1f];
}
void k051649_device::k051649_volume_w(offs_t offset, u8 data)
{
m_stream->update();
m_channel_list[offset].volume = data & 0xf;
}
void k051649_device::k051649_frequency_w(offs_t offset, u8 data)
{
const int freq_hi = offset & 1;
offset >>= 1;
m_stream->update();
// update frequency
if (freq_hi)
m_channel_list[offset].frequency = (m_channel_list[offset].frequency & 0x0ff) | (data << 8 & 0xf00);
else
m_channel_list[offset].frequency = (m_channel_list[offset].frequency & 0xf00) | data;
// test register bit 5 resets the internal counter
if (m_test & 0x20)
m_channel_list[offset].counter = 0;
// sample reload pending
m_channel_list[offset].clock = -1;
}
void k051649_device::k051649_keyonoff_w(u8 data)
{
m_stream->update();
for (int i = 0; i < 5; i++)
{
m_channel_list[i].key = BIT(data, i);
}
}
void k051649_device::k051649_test_w(u8 data)
{
m_test = data;
}
u8 k051649_device::k051649_test_r(address_space &space)
{
u8 data = space.unmap();
// reading the test register triggers a write
if (!machine().side_effects_disabled())
k051649_test_w(data);
return data;
}
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