NORWOOD, Mass. — Analog Devices Inc. has worked closely with 3Com Corp. to integrate a controllerless V.90 chip set with a silicon-based data access arrangement (DAA) directly on a PCI/CardBus interface. Meir Dahan, the WinModem and xDSL development manager at 3Com, said the new AD1807/1804 chip-set design could represent the standard PC Card form factor design for 3Com WinModems moving forward, and also represents an important starting point for integrating future xDSL services in a PC Card chip set.
Motorola Inc.'s software products division, meanwhile, unveiled its first direct motherboard implementation of the AC-Link soft-modem chip-set family at last week's Intel Developer Forum in Palm Springs, Calif. Like the ADI/3Com solution, the Motorola SM56 AC-L design leverages the work in silicon DAAs, which make the board space for direct motherboard implementations appropriate for the first time.
ADI's work with 3Com is a special relationship under which 3Com will have sole rights for a specified time to the AD1807 data pump and the AD1804 silicon DAA. While the former chip is based on the 49-Mips ADSP-2189 core, ADI product line director Maury Wood said that 3Com helped develop much of the code for the device and also developed code for a special voice codec, the AD1803, which is used with the chip set for WinModem.
The AD1807 is unique in integrating a comprehensive PCI, CardBus and "sub-ISA" interface for a variety of small-form-factor buses. It also has 80 kbytes of SRAM, 12 kbytes of ROM, a special 5-V/3.3-V voltage regulator for the device's 2.5-V core and an interface for the AC-Link. The latter is a special riser interface developed in part by Intel to ease international "homologation," or agreement, on modem standards.
3Com has a separate pact with Silicon Labs Inc. (Austin, Texas) to offer that company's silicon DAA along with DSP architectures from Texas Instruments Inc. For the WinModems based on ADI's DSP, however, 3Com and ADI jointly developed their own silicon DAA design, which ADI can offer at a later date as the AD1804. In a controllerless environment, Wood and Dahan said, the 1804/1807 combination represents the tightest integration so far in placing a maximum amount of intelligence on the PC Card.
Motorola, meanwhile, has taken an opposite path in add-in card and motherboard designs by emphasizing soft functionality, where many function calls are handed off to the host processor. Motorola already had used the SM56 AC-L chip-set design in a variety of modem-riser and daughtercard applications and had received Microsoft Windows logo certification for the chip set in July.
The key to bringing the design to motherboards, said software products marketing director Michael Tramontano, was to use Motorola's own silicon DAA with the data-pump peripheral. Intel announced at IDF that this Motorola design will be standardized in Intel's FlexATX desktop motherboard family. The entire modem design typically occupies two square inches of board space.
"The motherboard segment is still an emerging market, but higher levels of integration for both the motherboard and daughtercard is where we'll be driving all designs in the future," said Tramontano.
