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msm5205.cpp : Add DAC output bit difference, Fix Data capture timing… (#6260)

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* msm5205.cpp : Add DAC output bit difference, Make Data capture timing related to input clock
Add notes for MSM5205 can be usable with 768kHz input clock (from official document), Cutoff Frequency, Correct MSM6585 timing note from official document

* msm5205.cpp : Fix descriptions
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cam900 2020-02-06 03:41:23 +09:00 committed by GitHub
parent 5c3cc9a045
commit 712cde0679
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2 changed files with 23 additions and 18 deletions
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38
src/devices/sound/msm5205.cpp
View File

@ -41,14 +41,15 @@
Differences between MSM6585 & MSM5205:
MSM6585 MSM5205
Master clock frequency 640kHz 384kHz
Sampling frequency 4k/8k/16k/32kHz 4k/6k/8kHz
ADPCM bit length 4-bit 3-bit/4-bit
Data capture timing 5µsec 15.6µsec
DA converter 12-bit 10-bit
Low-pass filter -40dB/oct N/A
Overflow prevent circuit Included N/A
MSM6585 MSM5205
Master clock frequency 640kHz 384k/768kHz
Sampling frequency 4k/8k/16k/32kHz at 640kHz 4k/6k/8kHz at 384kHz
ADPCM bit length 4-bit 3-bit/4-bit
Data capture timing 3µsec at 640kHz 15.6µsec at 384kHz
DA converter 12-bit 10-bit
Low-pass filter -40dB/oct N/A
Overflow prevent circuit Included N/A
Cutoff Frequency (Sampling Frequency/2.5)kHz N/A
Data capture follows VCK falling edge on MSM5205 (VCK rising edge on MSM6585)
@ -57,21 +58,22 @@
*/
DEFINE_DEVICE_TYPE(MSM5205, msm5205_device, "msm5205", "MSM5205")
DEFINE_DEVICE_TYPE(MSM6585, msm6585_device, "msm6585", "MSM6585")
DEFINE_DEVICE_TYPE(MSM5205, msm5205_device, "msm5205", "OKI MSM5205 ADPCM")
DEFINE_DEVICE_TYPE(MSM6585, msm6585_device, "msm6585", "OKI MSM6585 ADPCM")
msm5205_device::msm5205_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock)
: msm5205_device(mconfig, MSM5205, tag, owner, clock)
: msm5205_device(mconfig, MSM5205, tag, owner, clock, 10)
{
}
msm5205_device::msm5205_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, u32 clock)
msm5205_device::msm5205_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, u32 clock, u8 dac_bits)
: device_t(mconfig, type, tag, owner, clock)
, device_sound_interface(mconfig, *this)
, m_s1(false)
, m_s2(false)
, m_bitwidth(4)
, m_dac_bits(dac_bits)
, m_vck_cb(*this)
, m_vck_legacy_cb(*this)
{
@ -79,7 +81,7 @@ msm5205_device::msm5205_device(const machine_config &mconfig, device_type type,
msm6585_device::msm6585_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock)
: msm5205_device(mconfig, MSM6585, tag, owner, clock)
: msm5205_device(mconfig, MSM6585, tag, owner, clock, 12)
{
}
@ -182,7 +184,7 @@ void msm5205_device::device_timer(emu_timer &timer, device_timer_id id, int para
m_vck = !m_vck;
m_vck_cb(m_vck);
if (!m_vck)
m_capture_timer->adjust(attotime::from_nsec(15600));
m_capture_timer->adjust(attotime::from_hz(clock()/6)); // 15.6 usec at 384KHz
break;
case TIMER_ADPCM_CAPTURE:
@ -244,7 +246,7 @@ WRITE_LINE_MEMBER(msm5205_device::vclk_w)
else
{
if (m_vck && !state)
m_capture_timer->adjust(attotime::from_nsec(15600));
m_capture_timer->adjust(attotime::from_hz(clock()/6)); // 15.6 usec at 384KHz
m_vck = state;
}
}
@ -337,6 +339,7 @@ WRITE_LINE_MEMBER(msm5205_device::s2_w)
void msm5205_device::device_clock_changed()
{
m_stream->set_sample_rate(clock());
int prescaler = get_prescaler();
if (prescaler != 0)
{
@ -364,7 +367,8 @@ void msm5205_device::sound_stream_update(sound_stream &stream, stream_sample_t *
/* if this voice is active */
if(m_signal)
{
short val = m_signal * 16;
const int dac_mask = (m_dac_bits >= 12) ? 0 : (1 << (12 - m_dac_bits)) - 1;
short val = (m_signal & ~dac_mask) * 16; // 10 bit DAC
while (samples)
{
*buffer++ = val;
@ -389,7 +393,7 @@ void msm6585_device::device_timer(emu_timer &timer, device_timer_id id, int para
m_vck = !m_vck;
m_vck_cb(m_vck);
if (m_vck)
m_capture_timer->adjust(attotime::from_usec(3));
m_capture_timer->adjust(attotime::from_hz(clock()/2)); // 3 usec at 640KHz
break;
case TIMER_ADPCM_CAPTURE:

3
src/devices/sound/msm5205.h
View File

@ -55,7 +55,7 @@ protected:
TIMER_ADPCM_CAPTURE
};
msm5205_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, u32 clock);
msm5205_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, u32 clock, u8 dac_bits);
// device-level overrides
virtual void device_start() override;
@ -83,6 +83,7 @@ protected:
u8 m_bitwidth; // bit width selector -3B/4B
s32 m_signal; // current ADPCM signal
s32 m_step; // current ADPCM step
u8 m_dac_bits; // DAC output bits (10 for MSM5205, 12 for MSM6585)
int m_diff_lookup[49*16];
devcb_write_line m_vck_cb;