SAA7780 データシートの表示（PDF） - Philips Electronics
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SAA7780 Datasheet PDF : 70 Pages
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Philips Semiconductors
Product Specification
ThunderBird Q3D PCI Audio
Accelerator
SAA7780
CD Quality Wavetable Synthesis with 320 Total Voices
ThunderBird Q3DTM includes two wavetable synthesis engines. When configured for wavetable synthesis only the
ActiMedia DSP can produce up to 64 wavetable 44KHz, 16 bit voices. Using the ActiMedia engine minimizes CPU
consumption and is ideal for games with MIDI music tracks. Also available is a professional quality soft-synth that can
produce up to 256 voices including special effects. The soft-synth is highly configurable and can be optimized for
highest quality with pure music applications or for minimum CPU consumption in gaming applications.
Both engines maximize quality and minimize cost by using system memory for wavetable sample sets and the
ActiMedia engine can be used to accelerate DirectMusic and DLS (Down Loadable Sound) sample sets using WDM
drivers.
ActiMedia DSP Architecture
The ActiMedia architecture combines the strengths of both programmable and fixed function DSP architectures. A
programmable DSP processor enables custom features, field up-grade and ease of development. An array of gate-
efficient fixed function DSP processors (accelerators) operate in parallel with the programmable DSP, providing an
extremely high performance-to-cost ratio. Unlike fixed-point DSP's that must use a single resolution for all audio
processing, each accelerator is designed with the optimum resolution for its function. This preserves the audio integrity
without the cost of a high-resolution or floating point programmable DSP implementation. The result is a performance,
quality and concurrency that requires 10 times the MIPS on a classical DSP architecture.
Digital Mode Dual Game Port
The S/W polling used by analog game ports can consume up to 10% of the host CPU. ThunderBird PCI products utilize
a digital operating mode that can eliminate S/W polling and accelerate the game port function resulting in significantly
improved system performance. Joystick buttons can be polled or interrupt driven to further enhance performance. A
default analog mode assures compatiblitiy with DOS and other non-DirectInputTM applications.
PCI Interface
The ThunderBird Q3DTM is a PCI 2.1 compliant multifunction device including audio, game port and 16650 UART
functions capable of bursting at 132 MB data rates. The high bandwidth and low latency of the PCI bus reduces the
need for host based processing and local memory. The PCI bus consumption of each audio stream is reduced by a
factor of 10 compared to ISA solutions. The PCI and CPU busses are no longer locked during slow ISA DMA
transactions and system performance is improved as much as 20%.
To maximize performance, the PCI interface includes dual 32 bit bus masters: DMA, DirectSound and wavetable
synthesis acceleration. A 16 bit DSP Master Device is used to transfer data directly between the host and DSP or AC97
interface. Additional slave devices support legacy and MIDI interfaces. All I/O is re-mappable creating a true "Plug and
Play" device.
Comprehensive Legacy Audio Support
SoundBlaster Pro compatibility in both Real Mode DOS and DOS windows is achieved through H/W SoundBlaster and
OPL 3 (FM) emulation registers. Legacy DMA over the PCI bus is supported on all major platforms utilizing PC/PCI,
DDMA, or VLSI's proprietary Legacy Accommodation ModeTM (LAMTM). DOS music synthesis includes stereo MIDI
playback, quad MIDI playback, and FM emulation.
Integrated I/O and Peripherals
ThunderBird Q3D products include all the required features to implement a PCI audio solution with minimal chip count.
I/O includes an AC97 link for a AC97 1.0 codec, stereo DAC serial port for multi-channel or low cost playback
1999 Sep 30
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