LM4560 Datasheet, PDF (1/54 Pages) National Semiconductor (TI) – Advanced PCI Audio Accelerator

December 1998
LM4560
Advanced PCI Audio Accelerator
General Description
LM4560 is an advanced PCI audio accelerator providing full
legacy compatibility, wavetable synthesis, DirectMusic, Di-
rectSound, and DirectSound3D on a single chip for the high-
performance, cost-sensitive consumer market. It supports
Sound Blaster functionality and is fully PC98 compliant.
The LM4560 integrates a 64-voice wave table engine with
per voice effect processing capability. It supports the upcom-
ing Microsoft™ DirectMusic API and is fully compatible with
DLS Level 1 (downloadable samples) specification. The
LM4560 is optimized for Microsoft Windows™ 98 and Win-
dows NT5.0 WDM streaming architecture with re-routable
end-point support. The LM4560 includes DirectSound3D ac-
celeration hardware for ITD (Interaural Time Difference), IID
(Interaural Intensity Difference), Pan, Delay, and Doppler
hardware.
The LM4560 supports Sound Blaster Pro/16 DOS games
while improving gaming audio quality. The LM4560 supports
both the legacy analog gameport and a Digital Enhanced
Game Port. When coupled with DirectInput™ driver, the Digi-
tal Enhanced Game Port can save up to 12% of the CPU
overhead nominally required by a conventional analog game
port. The LM4560 employs a high precision 26-bit digital
mixer, providing an accurate 20-bit output and higher than 90
dB signal-to-noise ratio when used with high quality AC97
Rev 1.03 and Rev 2.0 codecs.
The LM4560 is designed with aggressive power manage-
ment. It is PCI Bus Power Management Interface (PPMI
1.0)-compliant. The LM4560 supports multiple Rev 2.0 AC97
codecs, which are useful for notebook docking systems.
With a low power, 3.3V process and a space conscious 100
TQFP package, the LM4560 is also well suited for Notebook
systems.
In summary, the LM4560 provides a balanced combination
of features and performance to the end-user. By combining
PCI bus mastering for DirectSound acceleration, Hardware
Wave table synthesizer, Digital Enhanced Game Port and
DirectSound 3D audio acceleration. It delivers high perfor-
mance, high quality audio, high-end features with efficient
power management in a space-efficient 100 TQFP package.
Features
n PCI 2.1-compliant with Bus Mastering optimized for
multiple stream operation
n On-chip per voice cache minimizes PCI bandwidth
n Up to 20X improvement over ISA DMA on PCI bus
bandwidth utilization
Advanced Wavetable Synthesizer
n Wavetable synthesis with 64-voices polyphony, which
supports all combinations of stereo/mono, 8-/16-bits,
and signed/unsigned samples
n Per channel volume, pitch shift, left/right pan, tremolo,
vibrato and envelope control (32 channels in hardware)
n Per channel effect process ing and effect volume control
for reverb, chorus, and echo
n DLS1-compliant Downloadable Samples support
Legacy Compatibility
n Legacy game audio support with SoundBlaster Pro/16
compatibility on the PCI bus
n Legacy DMA support on PCI Bus with DDMA-enabled or
standard (non-DDMA) PCI chipsets
n FM through realtime FM-to-wavetable conversion
n MPU-401 compatible UART for external or internal
synthesis
n General MIDI/GS command interpretation for wavetable
& effect synthesis
High Quality Audio and AC97 Support
n CD quality audio with higher than 90 dB signal-to-noise
ratio using an external high quality AC97 codec
n AC97 support with full duplex, independent sample rate
converter for audio recording and playback
n On-chip sample rate converter ensures all internal
operation at 48 kHz
n High precision internal 26-bit digital mixer with 16- and
20-bit digital audio output
Advanced Streaming Architecture
n Microsoft WDM Streaming architecture compliant and
“Re-routable endpoint” support
n Three stereo capture channels
n AC97 stereo recording channel through AC-link
DirectSound 3D
n 64-voices DirectSound channels
n 32-voices DirectSound3D accelerator with IID, ITD, and
Doppler effects on 3D positional audio buffers
n DirectSound accelerator for volume, pan, and pitch shift
control on streaming or static buffers
Telephony & Modem
n Full duplex speaker phone with AC97 2.0 audio-modem
codec
n Fax-modem with host based software
Extras
n Fully Plug and Play PCI controller and software
n Digital Enhanced Game port enables an analog joystick
to emulate digital joystick performance using the
National Semiconductor-provided DirectInput driver. This
eliminates up to 12% CPU overhead wasted on joystick
polling.
TRI-STATE^® is a registered trademark of National Semiconductor Corporation.
Microsoft™ is a trademark of Microsoft Corporation.
Windows^® is a registered trademark of Microsoft Corporation.
DirectInput™ is a trademark of Microsoft Corporation
© 1998 National Semiconductor Corporation DS100910
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