AD1846_15 Datasheet, PDF (1/28 Pages) Analog Devices – Low Cost Parallel-Port 16-Bit SoundPort Stereo Codec

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Low Cost Parallel-Port 16-Bit
SoundPort Stereo Codec
AD1846
FEATURES
It provides a direct, byte-wide interface to both ISA (“AT”) and
Low Cost, Pin- and Register-Compatible Alternative to EISA computer buses for simplified implementation on a com-
AD1848
puter motherboard or add-in card. The AD1846 generates en-
Single-Chip Integrated ∑∆ Digital Audio Stereo Codec
able and direction controls for IC buffers such as the 74_245.
Supports the Microsoft Windows Sound System*
The AD1846 SoundPort Stereo Codec supports a DMA re-
Multiple Channels of Stereo Input and Output
quest/grant architecture for transferring data with the host com-
Analog and Digital Signal Mixing
puter bus. One or two DMA channels can be supported.
OBSOLETE Programmable Gain and Attenuation
On-Chip Signal Filters
Digital Interpolation and Decimation
Analog Output Low-Pass
Sample Rates from 5.5 kHz to 48 kHz
68-Lead PLCC Package
Operation from +5 V Supply
Byte-Wide Parallel Interface to ISA and EISA Buses
Supports One or Two DMA Channels and
Programmed I/O
PRODUCT OVERVIEW
The Parallel-Port AD1846 SoundPort^® Stereo Codec integrates
key audio data conversion and control functions into a single in-
tegrated circuit. The AD1846 is intended to provide a complete,
single-chip audio solution for business audio and multimedia
applications requiring operation from a single +5 V supply.
Programmed I/O (PIO) mode is also supported for control reg-
ister accesses and for applications lacking DMA control. Two
input control lines support mixed direct and indirect addressing
of twenty-one internal control registers over this asynchronous
interface.
External circuit requirements are limited to a minimal number
of low cost support components. Anti-imaging DAC output
filters are incorporated on-chip. DAC dynamic range exceeds
80 dB over the 20 kHz audio band. Sample rates from 5.5 kHz
to 48 kHz are supported from external crystals.
The Codec includes a stereo pair of ∑∆ analog-to-digital con-
verters and a stereo pair of ∑∆ digital-to-analog converters. In-
puts to the ADC can be selected from four stereo pairs of analog
signals: line, microphone (“mic”), auxiliary (“aux”) line #1, and
post-mixed DAC output. A software-controlled programmable
gain stage allows independent gain for each channel going into
the ADC. The ADCs’ output can be digitally mixed with the
*Windows Sound System is a trademark of Microsoft Corp.
SoundPort is a registered trademark of Analog Devices, Inc.
DACs’ input.
(Continued on page 9)
FUNCTIONAL BLOCK DIAGRAM
ANALOG
ANALOG
SUPPLY
DIGITAL
SUPPLY
CRYSTALS
POWER DOWN
DIGITAL
L_LINE
R_LINE
L_MIC
R_MIC
L_AUX1
R_AUX1
L_OUT
R_OUT
L_AUX2
R_AUX2
MUX
L
GAIN
R
GAIN
∑∆ A/D
16
CONVERTER
∑∆ A/D
16
CONVERTER
GAIN/ATTEN/
MUTE
AD1846
OSCILLATORS
µ/
A
P
L
A
A
R
W
A
L
L
DIGITAL
E
MIX
L
L
∑
ATTEN/
MUTE
ANALOG
FILTER
∑∆ D/A
CONVERTER
R
∑
ATTEN/
MUTE
ANALOG
FILTER
∑∆ D/A
CONVERTER
INTERPOL ATTENUATE ∑
INTERPOL ATTENUATE
∑
P
µ/ _O
AR
L
T
A
W
GAIN/ATTEN/
MUTE
REFERENCE
CONTROL
REGS
PLAYBACK REQ
PLAYBACK ACK
CAPTURE REQ
CAPTURE ACK
ADR1:0
DATA7:0
CS
WR
RD
BUS DRIVER
CONTROL
HOST DMA
INTERRUPT
EXTERNAL
CONTROL
V_REF
REV. A
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