a
Internet Gateway Processor
ADSP-21mod870
FEATURES
PERFORMANCE
Complete Single-Chip Internet Gateway Processor (No
External Memory Required)
Implements V.34/V.90 Data/FAX Modem Including
Controller and Datapump
19 ns Instruction Cycle Time @ 3.3 V, 52 MIPS Sustained
Performance
Open Architecture Platform Extensible to Voice Over IP
and Other Applications
Low Power Dissipation, 80 mW (Typical) for Digital
Modem
Power-Down Mode Featuring Low CMOS Standby
Power Dissipation
INTEGRATION
ADSP-2100 Family Code Compatible, with Instruction
Set Extensions
160K Bytes of On-Chip RAM, Configured as 32K Words
On-Chip Program Memory RAM and 32K Words OnChip Data Memory RAM
Dual Purpose Program Memory for Both Instruction
and Data Storage
Independent ALU, Multiplier/Accumulator and Barrel
Shifter Computational Units
Two Independent Data Address Generators
Powerful Program Sequencer Provides Zero Overhead
Looping Conditional Instruction Execution
Programmable 16-Bit Interval Timer with Prescaler
100-Lead LQFP with 0.4 Square Inch (256 mm2) Footprint
SYSTEM INTERFACE
16-Bit Internal DMA Port for High Speed Access to OnChip Memory (Mode Selectable)
Two Double-Buffered Serial Ports with Companding
Hardware and Automatic Data Buffering
Programmable Multichannel Serial Port Supports
24/32 Channels
Automatic Booting of On-Chip Program Memory
Through Internal DMA Port
Six External Interrupts
13 Programmable Flag Pins Provide Flexible System
Signaling
ICE-Port™ Emulator Interface Supports Debugging in
Final Systems
ICE-Port is a trademark of Analog Devices, Inc.
All other trademarks are the property of their respective holders.
FUNCTIONAL BLOCK DIAGRAM
POWER-DOWN
CONTROL
DATA ADDRESS
GENERATORS
FULL MEMORY
MODE
MEMORY
PROGRAM
SEQUENCER
DAG 1 DAG 2
16K؋24 PM
8K؋24 OVERLAY 1
8K؋24 OVERLAY 2
16K؋16 DM
8K؋16 OVERLAY 1
8K؋16 OVERLAY 2
PROGRAMMABLE
I/O
AND
FLAGS
EXTERNAL
ADDRESS
BUS
EXTERNAL
DATA
BUS
PROGRAM MEMORY ADDRESS
DATA MEMORY ADDRESS
BYTE DMA
CONTROLLER
PROGRAM MEMORY DATA
OR
DATA MEMORY DATA
EXTERNAL
DATA
BUS
ARITHMETIC UNITS
ALU
MAC
SHIFTER
SERIAL PORTS
TIMER
SPORT 0 SPORT 1
ADSP-2100 BASE
ARCHITECTURE
INTERNAL
DMA
PORT
HOST MODE
GENERAL DESCRIPTION
The ADSP-21mod870 is a single-chip Internet gateway processor optimized for implementation of a complete V.34/56K
modem. All data pump and controller functions can be implemented on a single chip, offering the lowest power consumption
and highest possible modem port density.
The ADSP-21mod870, shown in the Functional Block Diagram, combines the ADSP-2100 family base architecture (three
computational units, data address generators and a program
sequencer) with two serial ports, a 16-bit internal DMA port, a
byte DMA port, a programmable timer, Flag I/O, extensive
interrupt capabilities and on-chip program and data memory.
The ADSP-21mod870 integrates 160K bytes of on-chip
memory configured as 32K words (24-bit) of program RAM,
and 32K words (16-bit) of data RAM. Power-down circuitry is
also provided to meet the low power needs of battery operated
portable equipment. The ADSP-21mod870 is available in
100-lead LQFP package.
Fabricated in a high speed, low power, CMOS process, the
ADSP-21mod870 operates with a 19 ns instruction cycle time.
Every instruction can execute in a single processor cycle.
The ADSP-21mod870’s flexible architecture and comprehensive instruction set allow the processor to perform multiple
operations in parallel. In one processor cycle the ADSP-21mod870
can:
•
•
•
•
•
Generate the next program address
Fetch the next instruction
Perform one or two data moves
Update one or two data address pointers
Perform a computational operation
REV. 0
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.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700
World Wide Web Site: http://www.analog.com
Fax: 781/326-8703
© Analog Devices, Inc., 1999
