// 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. It is actually well researched and documented: http://bifi.msxnet.org/msxnet/tech/scc.html Thanks to Sean Young (sean@mess.org) for some bugfixes. K052539 is more or less equivalent to this chip except channel 5 does not share waveram with channel 4. ***************************************************************************/ #include "emu.h" #include "k051649.h" #include #define FREQ_BITS 16 #define DEF_GAIN 8 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_mclock(0) , m_rate(0) , m_mixer_table(nullptr) , m_mixer_lookup(nullptr) , m_test(0) { } //------------------------------------------------- // device_start - device-specific startup //------------------------------------------------- void k051649_device::device_start() { // get stream channels m_rate = clock()/16; m_stream = stream_alloc(0, 1, m_rate); m_mclock = clock(); // allocate a buffer to mix into - 1 second's worth should be more than enough m_mixer_buffer.resize(2 * m_rate); // build the mixer table make_mixer_table(5); // save states for (int voice = 0; voice < 5; voice++) { save_item(NAME(m_channel_list[voice].counter), voice); save_item(NAME(m_channel_list[voice].frequency), voice); save_item(NAME(m_channel_list[voice].volume), voice); save_item(NAME(m_channel_list[voice].key), voice); save_item(NAME(m_channel_list[voice].waveram), voice); } 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.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() { const u32 old_rate = m_rate; m_rate = clock()/16; m_mclock = clock(); if (old_rate < m_rate) { m_mixer_buffer.resize(2 * m_rate, 0); } m_stream->set_sample_rate(m_rate); } //------------------------------------------------- // sound_stream_update - handle a stream update //------------------------------------------------- void k051649_device::sound_stream_update(sound_stream &stream, stream_sample_t **inputs, stream_sample_t **outputs, int samples) { // zap the contents of the mixer buffer std::fill(m_mixer_buffer.begin(), m_mixer_buffer.end(), 0); for (sound_channel &voice : m_channel_list) { // channel is halted for freq < 9 if (voice.frequency > 8) { const int v = voice.volume * voice.key; int c = voice.counter; const int step = ((s64(m_mclock) << FREQ_BITS) / float((voice.frequency + 1) * 16 * (m_rate / 32))) + 0.5f; // add our contribution for (int i = 0; i < samples; i++) { c += step; const int offs = (c >> FREQ_BITS) & 0x1f; m_mixer_buffer[i] += (voice.waveram[offs] * v) >> 3; } // update the counter for this voice voice.counter = c; } } // mix it down stream_sample_t *buffer = outputs[0]; for (int i = 0; i < samples; i++) *buffer++ = m_mixer_lookup[m_mixer_buffer[i]]; } /********************************************************************************/ 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) { // test-register bits 6/7 expose the internal counter if (m_test & 0xc0) { m_stream->update(); if (offset >= 0x60) offset += (m_channel_list[3 + (m_test >> 6 & 1)].counter >> FREQ_BITS); else if (m_test & 0x40) offset += (m_channel_list[offset >> 5].counter >> FREQ_BITS); } return m_channel_list[offset >> 5].waveram[offset & 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) { // test-register bit 6 exposes the internal counter if (m_test & 0x40) { m_stream->update(); offset += (m_channel_list[offset >> 5].counter >> FREQ_BITS); } return m_channel_list[offset >> 5].waveram[offset & 0x1f]; } void k051649_device::k051649_volume_w(offs_t offset, u8 data) { m_stream->update(); m_channel_list[offset & 0x7].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(); // test-register bit 5 resets the internal counter if (m_test & 0x20) m_channel_list[offset].counter = ~0; else if (m_channel_list[offset].frequency < 9) m_channel_list[offset].counter |= ((1 << FREQ_BITS) - 1); // 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; } 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() { // reading the test register sets it to $ff! if (!machine().side_effects_disabled()) k051649_test_w(0xff); return 0xff; } //------------------------------------------------- // build a table to divide by the number of voices //------------------------------------------------- void k051649_device::make_mixer_table(int voices) { // allocate memory m_mixer_table = std::make_unique(512 * voices); // find the middle of the table m_mixer_lookup = m_mixer_table.get() + (256 * voices); // fill in the table - 16 bit case for (int i = 0; i < (voices * 256); i++) { const int val = std::min(32767, i * DEF_GAIN * 16 / voices); m_mixer_lookup[ i] = val; m_mixer_lookup[-i] = -val; } }