Analog Devices Inc. ADSP-21MOD885-000

Overview

ADSP-21MOD885-000 from Analog Devices is a single-chip Internet gateway processor optimized for V.34/V.90 data/fax modem implementation, integrating 32K × 24-bit program RAM, 32K × 16-bit data RAM, dual synchronous serial ports (SPORT0/SPORT1), and a 16-bit internal DMA port. It delivers 52 MIPS sustained performance at 19 ns instruction cycle time with 80 mW typical power dissipation in digital modem operation.

For engineers reviewing the ADSP-21MOD885-000 datasheet, ADSP-21MOD885-000 pinout, ADSP-21MOD885-000 application, or ADSP-21MOD885-000 equivalent, key selection criteria include on-chip memory configuration, serial port companding support (A-law/µ-law per G.711), IDMA/BDMA interface modes, power-down interrupt handling, and ICE-Port™ emulator compatibility for in-system debugging.

Technical Context

The ADSP-21MOD885-000 implements the ADSP-2100 base architecture with three parallel computational units (ALU, MAC, shifter), two independent DAGs, and zero-overhead looping via hardware loop stacks. Its instruction set supports simultaneous dual operand fetches-one from program memory and one from data memory-enabling full 52 MIPS throughput without external memory dependency.

It operates in two configurable system modes: Full Memory Mode (14-bit address bus, 24-bit data bus) for BDMA overlay expansion, or Host Mode (16-bit multiplexed IDMA address/data bus) for direct host processor coupling. Serial port framing, clock sourcing (internal/external), and SPORT1 reconfiguration for IRQ0/IRQ1/Flag I/O are software-controlled via system registers.

Key Specifications

Pinout & Package

The ADSP-21MOD885-000 is housed in a 100-lead LQFP package (0.4 inch × 0.4 inch, 256 mm² footprint) with multiplexed functionality on serial port, flag, interrupt, and external bus pins. Pin configuration is determined at RESET (mode pins) or during runtime (SPORT software control).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Internet gateway processor applications.

Compared with ADSP-21MOD870, the ADSP-21MOD885-000 offers identical hardware compatibility but includes enhanced bootloader integrity checks and longer-term manufacturing availability; versus TMS320C549, it delivers turnkey V.90 compliance with no external memory or firmware development overhead.

Availability

ADSP-21MOD885-000 is available at Aetrix Electronics and suitable for V.90 modem terminals, T1-based multi-channel gateways, and VoIP edge devices requiring stable component supply across long-lifecycle industrial deployments.

Supply support for ADSP-21MOD885-000 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Analog Devices is a global leader in high-performance analog, mixed-signal, and DSP technology, serving precision instrumentation, communications, and industrial control markets since 1965.

The ADSP-21MOD885-000 belongs to the ADSP-2100 family of fixed-point digital signal processors engineered specifically for real-time telecom infrastructure-emphasizing single-chip modem integration, low-power operation, and in-system debug capability.

FAQ

What is the primary function of the ADSP-21MOD885-000 in modem applications?

The ADSP-21MOD885-000 serves as a complete single-chip Internet gateway processor implementing both V.34 and V.90 data/fax modem controller and datapump functions. It executes all modulation, error correction, compression, and host interface protocols directly from on-chip SRAM without external memory. The ADSP-21MOD885-000 integrates dual serial ports with G.711 companding, a 16-bit IDMA port for host coupling, and power management features tailored for modem port density and battery operation.

Does the ADSP-21MOD885-000 require external memory to operate as a V.90 modem?

No, the ADSP-21MOD885-000 does not require external memory to operate as a V.90 modem. It contains 160 KB of on-chip RAM-configured as 32K × 24-bit program memory and 32K × 16-bit data memory-sufficient to hold the full modem software stack including datapump algorithms, command interpreters, and statistics reporting. The ADSP-21MOD885-000 supports dynamic firmware loading via its 16-bit IDMA port, but boot-time operation is fully self-contained.

How does the ADSP-21MOD885-000 handle power management in portable modem designs?

The ADSP-21MOD885-000 provides three hardware-supported low-power states: Power-Down (400-cycle wake-up latency), Idle, and Slow Idle (with 16/32/64/128× clock divisor). Its 80 mW typical active power and dedicated PWD/PWDACK signals enable rapid transition between active and dormant states during call setup, negotiation, and idle periods. The ADSP-21MOD885-000 maintains full interrupt responsiveness-including nonmaskable power-down interrupt-even in reduced-clock modes.

Can the ADSP-21MOD885-000 be used in multi-channel T1 gateway systems?

Yes, the ADSP-21MOD885-000 is explicitly designed for multi-channel T1 gateway applications. Its SPORT0 supports 24- or 32-channel time-division multiplexed serial bitstreams, allowing direct interface to T1 framer ICs like the ADSP-2181. Reference designs such as the ADSP-21mod870-EV1 demonstrate scalable architectures supporting up to 32 ADSP-21MOD885-000 devices per SHARC host, with each ADSP-21MOD885-000 handling independent channel processing including echo cancellation and protocol negotiation.

What debugging capabilities does the ADSP-21MOD885-000 provide for firmware development?

The ADSP-21MOD885-000 integrates a 14-pin ICE-Port™ emulator interface supporting in-target debugging without removing the device from the circuit. It enables real-time register and memory inspection, up to 20 hardware breakpoints, single-step or full-speed execution, PC upload/download, and C source-level debugging via compatible ADSP-2100 development tools. The ADSP-21MOD885-000's ICE-Port requires no mechanical adapters and fits within final PCB layouts due to its compact footprint and simplified connector requirements.