Features
| • | PCI 2.1-compliant with Bus Mastering optimized for multiple stream operation |
| • | On-chip per voice cache minimizes PCI bandwidth |
| • | Up to 20X improvement over ISA DMA on PCI bus bandwidth utilization |
Advanced Wavetable Synthesizer
| • | Wavetable synthesis with 64-voices polyphony, which supports all combinations of stereo/mono, 8-/16-bits, and signed/unsigned samples |
| • | Per channel volume, pitch shift, left/right pan, tremolo, vibrato and envelope control (32 channels in hardware) |
| • | Per channel effect process ing and effect volume control for reverb, chorus, and echo |
| • | DLS1-compliant Downloadable Samples support |
Legacy Compatibility
| • | Legacy game audio support with SoundBlaster Pro/16 compatibility on the PCI bus |
| • | Legacy DMA support on PCI Bus with DDMA-enabled or standard (non-DDMA) PCI chipsets |
| • | FM through realtime FM-to-wavetable conversion |
| • | MPU-401 compatible UART for external or internal synthesis |
| • | General MIDI/GS command interpretation for wavetable & effect synthesis |
High Quality Audio and AC97 Support
| • | CD quality audio with higher than 90 dB signal-to-noise ratio using an external high quality AC97 codec |
| • | AC97 support with full duplex, independent sample rate converter for audio recording and playback |
| • | On-chip sample rate converter ensures all internal operation at 48 kHz |
| • | High precision internal 26-bit digital mixer with 16- and 20-bit digital audio output |
Advanced Streaming Architecture
| • | Microsoft WDM Streaming architecture compliant and "Re-routable endpoint" support |
| • | Three stereo capture channels |
| • | AC97 stereo recording channel through AC-link |
DirectSound 3D
| • | 64-voices DirectSound channels |
| • | 32-voices DirectSound3D accelerator with IID, ITD, and Doppler effects on 3D positional audio buffers |
| • | DirectSound accelerator for volume, pan, and pitch shift control on streaming or static buffers |
Telephony & Modem
| • | Full duplex speaker phone with AC97 2.0 audio-modem codec |
| • | Fax-modem with host based software |
Extras
| • | Fully Plug and Play PCI controller and software |
| • | 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. |
| • | DirectX timer for video/audio synchronization |
| • | Forward pin-compatible with future PCI audio accelerators |
| • | 100-pin TQFP package |
| • | 3.3V operation |
Software Support
| • | Complete DirectX driver suite (DirectSound3D, DirectSound, DirectMusic, and DirectInput) for Windows 95 and Windows 98/NT 5.0 |
| • | Configuration installation, and diagnostics under real mode DOS, WindowsWindows 95, and Windows 98 DOS box |
| • | Windows 3.1, 95, NT4.0, Windows 98/NT5.0 configuration, installation, and mixer program |
| • | 1, 2, 4, or 8 Mbytes General MIDI (GM)/General Sound (GS) compliant sample Library |
Description LM4560 is an advanced PCI audio accelerator providing full legacy compatibility, wavetable synthesis, DirectMusic, DirectSound, 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 upcoming Microsoft DirectMusic API and is fully compatible with DLS Level 1 (downloadable samples) specification. The LM4560 is optimized for Microsoft Windows 98 and Windows NT5.0 WDM streaming architecture with re-routable end-point support. The LM4560 includes DirectSound3D acceleration 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 Digital 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 management. 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 performance, high quality audio, high-end features with efficient power management in a space-efficient 100 TQFP package.
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