Sprinter/mame
2
0
Fork 0
mirror of https://github.com/holub/mame synced 2025-04-23 00:39:36 +03:00
Code Issues Actions 1 Packages Projects Releases Wiki Activity

cbus/pc9801_86.cpp: attempt to resolve DAC FIFO under/overflows

Browse Source
This commit is contained in:
angelosa 2024-11-12 21:23:03 +01:00
parent 878d70d975
commit d566c8f76b
2 changed files with 52 additions and 29 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

76
src/devices/bus/cbus/pc9801_86.cpp
View File

@ -2,32 +2,33 @@
// copyright-holders:Angelo Salese
/**************************************************************************************************
NEC PC-9801-86 sound card
NEC PC-9801-SpeakBoard sound card
Mad Factory Otomi-chan Kai sound card
NEC PC-9801-86 sound card
NEC PC-9801-SpeakBoard sound card
Mad Factory Otomi-chan Kai sound card
Similar to PC-9801-26, this one has YM2608 instead of YM2203 and an
additional DAC port
Similar to PC-9801-26, this one has YM2608 instead of YM2203 and an
additional DAC port
SpeakBoard sound card seems to be derived design from -86, with an additional
OPNA mapped at 0x58*
SpeakBoard sound card seems to be derived design from -86, with an additional
OPNA mapped at 0x58*
Otomi-chan Kai is a doujinshi sound card based off SpeakBoard design.
It uses YM3438 OPL2C mapped at 0x78*, and anything that uses the nax.exe sound driver
expects this to be installed as default (cfr. datsumj).
To fallback to a regular -26/-86 board user needs to add parameter switches "-2" or "-3"
respectively, cfr. "nax -?" for additional details.
Otomi-chan Kai is a doujinshi sound card based off SpeakBoard design.
It uses YM3438 OPL2C mapped at 0x78*, and anything that uses the nax.exe sound driver
expects this to be installed as default (cfr. datsumj).
To fallback to a regular -26/-86 board user needs to add parameter switches "-2" or "-3"
respectively, cfr. "nax -?" for additional details.
TODO:
- Test all pcm modes;
- Make volume work;
- Recording;
- SpeakBoard: no idea about software that uses this, also board shows a single YM2608B?
"-86 only supports ADPCM instead of PCM, while SpeakBoard has OPNA + 256 Kbit RAM";
- Otomi-chan Kai: find a manual (マニュアル), it's mentioned with nax usage.
Very low-res scan of the PCB sports a 4-bit dip-sw bank at very least;
- Otomi-chan Kai: unknown ID port readback;
- verify sound irq;
TODO:
- Test all pcm modes;
- Fix PCM overflow bug properly (CPUENB signal yield host CPU until DAC catches up?)
- Make volume work;
- Recording;
- SpeakBoard: no idea about software that uses this, also board shows a single YM2608B?
"-86 only supports ADPCM instead of PCM, while SpeakBoard has OPNA + 256 Kbit RAM";
- Otomi-chan Kai: find a manual (マニュアル), it's mentioned with nax usage.
Very low-res scan of the PCB sports a 4-bit dip-sw bank at very least;
- Otomi-chan Kai: unknown ID port readback;
- verify sound irq;
**************************************************************************************************/
@ -368,14 +369,21 @@ void pc9801_86_device::io_map(address_map &map)
return 0;
}),
NAME([this] (u8 data) {
// HACK: on overflow make sure to single step the FIFO enough to claim some space back
// os2warp3 initializes the full buffer with 0x00 then quickly pretends
// that DAC already catched up by the time the actual startup/shutdown chimes are sent.
if (queue_count() == QUEUE_SIZE)
{
dac_transfer();
logerror("Warning: $a46c write with FIFO overflow %02x\n", m_pcm_mode);
}
if(queue_count() < QUEUE_SIZE)
{
m_queue[m_head++] = data;
m_head %= QUEUE_SIZE;
m_count++;
}
// TODO: what should happen on overflow?
// os2warp3 startup / shutdown chimes do this already
})
);
}
@ -424,12 +432,8 @@ u8 pc9801_86_device::queue_pop()
return ret;
}
TIMER_CALLBACK_MEMBER(pc9801_86_device::dac_tick)
void pc9801_86_device::dac_transfer()
{
m_pcm_clk = !m_pcm_clk;
if((m_pcm_ctrl & 0x40) || !(m_pcm_ctrl & 0x80))
return;
switch(m_pcm_mode & 0x70)
{
case 0x70: // 8bit stereo
@ -461,6 +465,20 @@ TIMER_CALLBACK_MEMBER(pc9801_86_device::dac_tick)
m_rdac->write(rsample);
} break;
}
}
TIMER_CALLBACK_MEMBER(pc9801_86_device::dac_tick)
{
m_pcm_clk = !m_pcm_clk;
if((m_pcm_ctrl & 0x40) || !(m_pcm_ctrl & 0x80))
return;
// TODO: verify underflow
// should leave the DACs in whatever state they are or ...?
if (!queue_count())
return;
dac_transfer();
if((queue_count() < m_irq_rate) && (m_pcm_ctrl & 0x20))
{
m_pcmirq = true;

5
src/devices/bus/cbus/pc9801_86.h
View File

@ -31,6 +31,9 @@ public:
pc9801_86_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock);
pc9801_86_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, uint32_t clock);
static constexpr feature_type unemulated_features() { return feature::MICROPHONE; }
static constexpr feature_type imperfect_features() { return feature::SOUND; }
protected:
void io_map(address_map &map) ATTR_COLD;
u8 pcm_control_r();
@ -74,6 +77,8 @@ private:
required_device<dac_16bit_r2r_twos_complement_device> m_rdac;
std::vector<u8> m_queue;
emu_timer *m_dac_timer;
void dac_transfer();
};
class pc9801_speakboard_device : public pc9801_86_device