// license:BSD-3-Clause // copyright-holders:Sandro Ronco /*************************************************************************** Videotone TVC 32/64 sound emulation ***************************************************************************/ #include "emu.h" #include "tvc.h" // device type definition DEFINE_DEVICE_TYPE(TVC_SOUND, tvc_sound_device, "tvc_sound", "TVC 64 Custom Sound") //------------------------------------------------- // tvc_sound_device - constructor //------------------------------------------------- tvc_sound_device::tvc_sound_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) : device_t(mconfig, TVC_SOUND, tag, owner, clock), device_sound_interface(mconfig, *this), m_write_sndint(*this) { } //------------------------------------------------- // device_start - device-specific startup //------------------------------------------------- void tvc_sound_device::device_start() { // resolve callbacks m_write_sndint.resolve_safe(); m_stream = machine().sound().stream_alloc(*this, 0, 1, machine().sample_rate()); m_sndint_timer = timer_alloc(TIMER_SNDINT); } //------------------------------------------------- // device_reset - device-specific reset //------------------------------------------------- void tvc_sound_device::device_reset() { m_enabled = 0; m_freq = 0; m_incr = 0; m_signal = 1; m_sndint_timer->reset(); } //------------------------------------------------- // device_timer - handler timer events //------------------------------------------------- void tvc_sound_device::device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr) { m_write_sndint(1); } //------------------------------------------------- // sound_stream_update - handle update requests for // our sound stream //------------------------------------------------- void tvc_sound_device::sound_stream_update(sound_stream &stream, stream_sample_t **inputs, stream_sample_t **outputs, int samples) { int rate = machine().sample_rate() / 2; if (m_enabled && m_freq) { while( samples-- > 0 ) { *outputs[0]++ = m_signal * (m_volume * 0x0800); m_incr -= m_freq; while(m_incr < 0) { m_incr += rate; m_signal = -m_signal; } } } else { // fill output with 0 if the sound is disabled memset(outputs[0], 0, samples * sizeof(stream_sample_t)); } } //------------------------------------------------- // ports write //------------------------------------------------- WRITE8_MEMBER(tvc_sound_device::write) { m_stream->update(); m_ports[offset] = data; switch(offset) { case 1: m_enabled = BIT(data, 4); // fall through case 0: { uint16_t pitch = (m_ports[0] | (m_ports[1]<<8)) & 0x0fff; m_freq = (pitch == 0x0fff) ? 0 : (int)(195312.5 / (4096 - pitch)); if ((m_ports[1] & 0x20) && m_freq != 0) m_sndint_timer->adjust(attotime::from_hz(m_freq), 0, attotime::from_hz(m_freq)); else m_sndint_timer->reset(); break; } case 2: m_volume = (data>>2) & 0x0f; break; } } //------------------------------------------------- // tvc_sound_device::reset_divider //------------------------------------------------- void tvc_sound_device::reset_divider() { m_stream->update(); m_incr = 0; m_signal = 1; if (m_ports[1] & 0x20 && m_freq != 0) m_sndint_timer->adjust(attotime::from_hz(m_freq), 0, attotime::from_hz(m_freq)); else m_sndint_timer->reset(); }