AD1821 Analog Devices, AD1821 Datasheet - Page 15

• Manufacturer Part Number: AD1821
• Manufacturer: Analog Devices

As the AD1821 contains SoundBlaster (compatible) and Windows
Sound System logical devices. You may find the following related
development kits useful when developing AD1821 applications.
The following reference texts can serve as additional sources of
information on developing applications that run on the
AD1821.
Multimedia PC Capabilities
The AD1821 is MPC-2 and MPC-3 compliant. This compli-
ance is achieved through the AD1821’s flexible mixer and the
embedded chip resources.
Music Synthesis
The AD1821 includes an embedded music synthesizer that
emulates industry standard OPL3 FM synthesizer chips and
delivers 20 voice polyphony. The internal synthesizer generates
digital music data at 22.05 kHz and is summed into the DACs
digital data stream prior to conversion. To sum synthesizer data
with the ADC output, the ADC must be programmed for a
22.05 kHz sample rate.
Wavetable MIDI Inputs
The AD1821 has a dedicated analog input for receiving an ana-
log wavetable synthesizer output. Alternatively, a wavetable
synthesizer’s I
nected to one of the AD1821’s I
table data from the AD1821’s I
other digital data streams being handled by the AD1821 and
then sent to the 16-bit
MIDI
The primary interface for communicating MIDI data to and
from the host PC is the compatible MPU-401 interface that
operates in UART mode. The MPU-401 interface has two
REV. 0
Developer Kit for SoundBlaster Series, 2nd ed. © 1993,
Creative Labs, Inc., 1901 McCarthy Blvd., Milpitas, CA 95035
Microsoft Windows Sound System Driver Development Kit (CD),
Version 2.0, © 1993, Microsoft Corp., One Microsoft Way,
Redmond, WA 98052
S. De Furia & J. Scacciaferro, The MIDI Implementation Book,
(© 1986, Third Earth, Pompton Lake)
C. Petzold, Programming Windows: the Microsoft guide to writ-
ing applications for Windows 3.1, 3rd. ed., (© 1992, Microsoft
Press, Redmond)
K. Pohlmann, Principles of Digital Audio, (© 1989, Sams,
Indianapolis)
A. Stolz, The SoundBlaster Book, (© 1993, Abacaus, Grand
Rapids)
J. Strawn, Digital Audio Engineering, An Anthology, (© 1985,
Kaufmann, Los Altos)
Yamamoto, MIDI Guidebook, 4th. ed., (© 1987, 1989,
Roland Corp.)
EuSynth-1+
2
S formatted digital output can be directly con-
DAC.
The synthesizer is a hardware
implementation of Eusynth-1+
code that was developed by
Euphonics, a research and devel-
opment company that specializes
in audio processing and electronic
music synthesis.
2
2
S port may be summed with
S serial ports. Digital wave-
–15–
built-in FIFOs: a 64 byte receive FIFO and a 16 byte transmit
FIFO.
Game Port
An IBM-compatible game port interface is provided on chip.
The game port supports up to two joysticks via a 15-pin D-sub
connector. Joystick registers supporting the Microsoft
Direct Input standard are included as part of the register map.
The AD1821 may be programmed to automatically sample the
game port and save the value in the Joystick Position Data Reg-
ister. When enabled, this feature saves up to 10% CPU MIPS
by off-loading the host from constantly polling the joystick port.
Volume Control
The registers that control the Master Volume output stage are
accessible through the parallel port. Master Volume output can
also be controlled through a 2-pin hardware interface. One pin
is used to increase the gain, the other pin attenuates the output
and both pins together entirely mute the output. Once muted, any
further activity of these pins will unmute the AD1821’s output.
Plug and Play Configuration
The AD1821 is fully Plug and Play configurable. For mother-
board applications, the built-in Plug and Play protocol can be
disabled with a software key providing a back door for the BIOS
to configure the AD1821’s logical devices. For information on
the Plug and Play mode configuration process, see the Plug and
Play ISA Specification Version 1.0a (May 5, 1994). All the
AD1821’s logical devices comply with Plug and Play resource
definitions described in the specification.
The AD1821 may alternatively be configured using an optional
Plug and Play Resource ROM. When the EEPROM is present,
some additional AD1821 muxed-pin features become available.
For example, pins that control an external modem logical device
are muxed with the DSP serial port. Some of these pin option
combinations are mutually exclusive (see Appendix A for more
information).
REFERENCES
The AD1821 also complies with the following related specifica-
tions; they can be used as an additional reference to AD1821 op-
erations beyond the material in this data sheet.
Plug and Play ISA Specification, Version 1.0a, © 1993, 1994,
Intel Corp. & Microsoft Corp., One Microsoft Way,
Redmond, WA 98052
Multimedia PC Level 2 Specification, © 1993, Multimedia PC
Marketing Council, 1730 M St. NW, Suite 707, Washington,
DC 20036
MIDI 1.0 Detailed Specification & Standard MIDI Files 1.0,
© 1994, MIDI Manufacturers Association, PO Box 3173
La Habra, CA 90632-3173
Recommendation G.711-Pulse Code Modulation (PCM) Of Voice
Frequencies ( -Law & A-Law Companding), The International
Telegraph and Telephone Consultative Committee IX Plenary
Assembly Blue Book, Volume III - Fascicle III.4, General
Aspects Of Digital Transmission Systems; Terminal
Equipment’s, Recommendations G.700 - G.795, (Geneva,
1988), ISBN 92-61-03341-5
IMA Digital Audio Doc-Pac (IMA-ADPCM), © 1992, Inter-
active Multimedia Association, 48 Maryland Avenue, Suite
202, Annapolis, MD 21401-8011
AD1821