SoundPort® Stereo Codec
Single-Chip Integrated ∑∆ Digital Audio Stereo Codec
Microsoft® and Windows® Sound System Compatible
MPC Level-2+ Compliant Mixing
16 mA Bus Drive Capability
Supports Two DMA Channels for Full Duplex Operation
On-Chip Capture and Playback FIFOs
Advanced Power-Down Modes
Programmable Gain and Attenuation
Sample Rates from 4.0 kHz to 50 kHz Derived from a
Single Clock or Crystal Input
68-Lead PLCC, 100-Lead TQFP Packages
Operation from +5 V Supplies
Byte-Wide Parallel Interface to ISA and EISA Buses
Pin Compatible with AD1848, AD1846, CS4248, CS4231
The Parallel Port AD1845 SoundPort Stereo Codec integrates
key audio data conversion and control functions into a single
integrated circuit. The AD1845 provides a complete, single chip
computer audio solution for business audio and multimedia
applications. The codec includes stereo audio converters, com-
plete on-chip filtering, MPC Level-2 compliant analog mixing,
programmable gain, attenuation and mute, a variable sample
frequency generator, FIFOs, and supports advanced power-
down modes. It provides a direct, byte-wide interface to both
ISA (“AT”) and EISA computer buses for simplified implemen-
tation on a computer motherboard or add-in card.
The AD1845 SoundPort Stereo Codec supports a DMA re-
quest/grant architecture for transferring data with the host com-
puter bus. One or two DMA channels can be supported.
Programmed I/O (PIO) mode is also supported for control
register accesses and for applications lacking DMA control.
Two input control lines support mixed direct and indirect ad-
dressing of thirty-seven internal control registers over this asyn-
chronous interface. The AD1845 includes dual DMA count
registers for full duplex operation enabling the AD1845 to cap-
ture data on one DMA channel and play back data on a separate
channel. The FIFOs on the AD1845 reduce the risk of losing
data when making DMA transfers over the ISA/EISA bus. The
FIFOs buffer data transfers and allow for relaxed timing in
acknowledging requests for capture and playback data.
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FUNCTIONAL BLOCK DIAGRAM
CLOCK SOURCE POWER DOWN
GAM = GAIN
SoundPort is a registered trademark of Analog Devices, Inc.
Microsoft and Windows are registered trademarks of Microsoft Corporation.
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
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© Analog Devices, Inc., 1997