GSM/GPRS/DCS1800/PCS1900 SoftFone

Baseband Chipset

REDUCE TOTAL SYSTEM COST WHILE
IMPROVING BATTERY LIFE IN GSM
HANDSET AND GPRS TERMINAL DESIGNS

The AD20msp430 baseband
processing chipset uses a
combination of GSM system
knowledge and advanced analog
and digital signal processing
technology to provide a new
benchmark in GSM/GPRS terminal
design.

The SoftFone

architecture is

entirely RAM-based. The software
is loaded from FLASH memory
and is executed from the on-chip
RAM. This allows fast develop-
ment cycles since no ROM-code
turns are required. Furthermore,
the handset software can be
updated in the field to enable new
features.

Combined with the Analog
Devices "Othello" RF chipset, a
complete multiband handset
design contains less than 200
components, fits in a 20 cm

single

sided PCB layout, and has a total
bill-of-materials cost 20-30% lower
than previous solutions.

The AD20msp430 is

Analog Devices' 4

generation GSM

baseband chipset,

providing additional

features, longer

standby time, and

lower cost through a

system approach to

the design.

FEATURES

Supports all voice codec algorithms FR (full-rate), EFR (enhanced
full-rate), and HR (half-rate) for compatibility with all GSM
networks

Provides data services in standard circuit-switched (14.4 kbps),
HSCSD (57.6 kbps), and GPRS (up to 115 kbps) modes

1 Mb on-chip SRAM, plus

8K DSP Program Memory, 8K DSP

Data Memory, and 4K DSP Cache

Standby current of 1 mA allows 6 weeks between battery charges
(1000 mAh battery)

Complete software protocol stacks available for voice and data
applications

Full suite of evaluation/development tools available, including
form-factor reference design

Programmable interface to Universal System Connector for
feature addition or system debugging

AD20msp430

AD20msp430 COMPRISES:

AD6522 GSM Digital Processor

The AD6522 digital engine includes
two high-performance, low-power
programmable processors. The DSP
engine uses the latest version of the
ADSP218x core, operating at 65
MIPS, and handling the vocoder
and channel codec functions. All
vocoder algorithms (FR, EFR, and
HR) are supported. The
microcontroller is the ARM7 RISC
engine, operating at 39 MIPS, and
handling the protocol stack and
man-machine interface (MMI)
functions.

The digital processor also includes
ciphering and Viterbi functions, as
well as a range of debugging tools
and interfaces for the FLASH
memory, keypad, display, SIM card,
IrDA, and USC ports. All instruc-
tions execute from on-chip RAM.

AD6521 Voiceband/Baseband Codec

The AD6521 chip contains all
analog and mixed-signal functions.
These include the I/Q channel A/D
and D/A converters, high-perfor-
mance multichannel voiceband
codec, and several auxiliary A/D and
D/A converters for AGC (automatic
gain control), AFC (automatic
frequency control), and power-
amplifier ramp control. The
AD6521 is intended for use with the
Analog Devices OthelloTM GSM
direct-conversion RF chipset.

Software and Development Tools

BOM COST REDUCTION THROUGH
SYSTEM ENGINEERING SKILL

The AD20msp430 chipset is
comprised of two chips, the
AD6522 DSP-based baseband
processor and the AD6521
voiceband/baseband mixed-
signal codec. Together with
the award-winning "Othello"
radio chipset, the
AD20msp430 allows a
significant reduction in the
component count and bill-of-
materials (BOM) cost of GSM
voice handsets and data
terminals.

The software and hardware
foundations of the
AD20msp430 chipset enjoy a
long history of successful
integration into GSM
handsets. This is Analog
Devices' 4

generation of

GSM chipsets, each of which
has passed numerous type-
approvals and network
operator approvals in OEM
handsets. In each generation,
additional features have been
added, while cost and power
have been reduced.

Numerous power-saving
features have been included in
the AD20msp430 chipset to
reduce the total power
consumption. A program-
mable state machine allows
events to be controlled with a
resolution of one-quarter of a
bit period. This reduces
current in standby mode to 1
mA. This allows a handset to
operate in standby mode for
up to 1000 hours on a battery
charge.

The AD20msp430 chipset uses
the SoftFoneTM architecture,
where all software resides in
RAM or FLASH memory.
Since ROM is not used,
development time is reduced
and additional features can be
field-installed easily. A basic
dual-band GSM terminal
typically requires a single 8Mb
FLASH memory chip.

A FULL SET OF DEVELOPMENT
TOOLS AND SOFTWARE

There are two processors in
the AD20msp430 chipset. The
DSP processor is the
ADSP218x core, proven in
previous generations of GSM
chipsets, and operated at 65
MIPS in the AD20msp430.
The microcontroller is an
ARM7TDMI, running at 39
MIPS. Both processors are
field-proven in digital wireless
applications.

The AD20msp430 chipset is
fully supported by a suite of
development tools and
software. The development
tools allow easy customization
of the DSP and/or ARM

controller software to allow
handset and terminal
manufacturers to optimize the
feature set and user interface
of the end equipment.
Software is available from
Analog Devices' software
partner TTPCom for all
layers, including both voice
and data applications, and is
updated as new features
become available.

Software written for the
AD20msp430 will not go out
of date. The system DMA and
interrupt controllers are
designed to allow easy
upgrades to future genera-
tions of DSP and controller
cores. The display interface
can be used with either
parallel or serial-interface
displays.

System development can be
shortened by the use of the
debugging features in the
AD20msp430. Most critical
signals can be routed under
software control to the
Universal System Connector.
This allows system debugging
to take place in the final form
factor. In addition, the
architecture includes high-
speed logger and address trace
functions in the DSP and
single-wire trace/debug in the
ARM controller.

ANALOG DEVICES: A LEADER IN
GSM

An established supplier of
components and solutions to
GSM handset manufacturers,
Analog Devices has an
incomparable track record of
high-volume, low-cost
manufacturing and delivery.
The company has provided
mixed-signal and baseband
processors for millions of GSM
handsets worldwide over
nearly 10 years. The
AD20msp410 was the first
open-market chipset/software
solution to achieve Type
Approval. Our software
partner TTPCom, is a
product-development and
engineering company based in
the United Kingdom. Formed
in 1988, TTPCom is a leading
independent developer of
GSM technology worldwide.

ANALOG DEVICES IN COMMUNI-
CATIONS

Analog Devices is recognized
for its unparalleled technical
capabilities in analog, digital,
and mixed-signal processing
used in RF signal processing,
data conversion, interfaces,
and total system design. The
company develops and offers
customers a wide range of
innovative wireless and
broadband wired communica-
tions products including
solutions for GSM, CDMA
(Code Division Multiple
Access); cellular base stations/
software radio; RF and IF
(intermediate frequency)
circuits, and xDSL. The
company is committed to
supplying the communications
industry with the highest
performance solutions at the
lowest possible cost.

www.analog.com

ŠAnalog Devices, Inc., 2000. All rights reserved.
Trademarks and registered trademarks are the
property of their respective companies.
ARM

is the registered trademark of ARM Limited.

H3790-5-1/00 (rev.0)

AD6522

AD6521

AD6523

AD6524

FLASH

Memory

Display

SIM

Keypad

AD20msp430 SoftFone

Chipset

Othello

Radio

Power

Control

1 Mbit
SRAM

DMA

I /O

ARM7

Controller

DSP

Memory

ADSP

218X

DSP

Voiceband

CODEC

Baseband

I /Q

A/D, D/A

Auxiliary

A/D, D/A

ADP 33XX
ADP 34XX

Power Management

Battery Charging

Multiband

Synthesizer

Direct

Conversion

Radio

A complete set of development tools
and emulators is available from
Analog Devices, including hardware
and software development tools,
and a reference design.

Part Number AD20MSP430