USB has arrived; 1394 is eyed

Electronic News, Dec 2, 1996 by Crista Hardie

Las Vegas--Universal Serial Bus (USB) has arrived, declared PC, peripheral and chip vendors here at Comdex on the first anniversary of the USB Implementers Forum. Those same vendors, meanwhile, are already turning their focus to the recently adopted IEEE 1394-1995 standard, a higher speed serial connection for multimedia peripherals, seen as a complementary interface to USB.

With nearly all 1997 shipments of consumer PCs expected to have USB capability, monitor and peripherals manufacturers are now demanding USB silicon from chip makers--and if the showing here was any indication, they will soon have it. A host of companies not only proclaimed support for USB, but showed USB-enabled consumer products, from keyboards and monitors to video phones. Chip offerings included multi-port hub devices, peripheral controllers and ASIC cores, most targeted for early-to mid-1997 shipment.

USB was initially developed for the x86-based PC platform, but can be adapted to Sparc, MIPS, Alpha or PowerPC. Apple is said to be taking a hard look at the interface. "In many ways, USB is helping to shape the multimedia PC of the coming decade," commented Patrick Yu, NEC Electronics ASIC strategic marketing engineer.

USB chips began trickling into the market last spring, led by Intel, but recent announcements from Philips Semiconductors, Texas Instruments and others indicated USB was "ready." Still, it wasn't until Microsoft decided to ship USB supplements to Windows 95 and fully support USB in all future Windows 95 shipments in August that the floodgate opened for the semiconductor and OEM product announcements leading into Comdex.

USB's allure is a standard, one-size-fits-all connection for low-speed (1.5-megabits-per-second) to medium-speed (12Mps) PC peripherals, as opposed to having several different parallel and serial ports on the back of a computer, such as SCSI and RS-232.

"(USB) will literally eliminate RS-232 in the space of five to seven years," asserted Paul Thomas, USB product marketing manager for Texas Instruments. Of course, USB can't quite keep up with the faster Ultra SCSI parallel interfaces now proposed to extend to 80MB/sec, but "There's also 1394 and Fibre Channel that are taking that space," Mr. Thomas said.

In fact, many of the companies supporting USB are also looking to the IEEE 1394-1995 200Mps serial interface as a way to connect PCs to higher end multimedia peripherals and consumer electronics, such as high-speed scanners and printers, digital set top boxes, video editing equipment and stereo equipment.

In addition, Intel's "sealed PC" initiative would make USB and 1394 standard interfaces on all PCs and ostensibly eliminate the need for any video, audio or telephony adapter boards. The sealed PC concept is still under scrutiny; however, many companies observed the complementary nature of the two serial technologies.

While the host and hub portions of the USB puzzle have garnered great support from chip makers, a near absence of peripheral controllers has been partly blamed for stalling the USB market. Recently, however, companies including TI, Atmel and NEC stepped up to fill that market space.

The first wave of peripheral, or function, controllers is expected to address low-speed mice, keyboards, joysticks and remote control units, although TI is already offering a full-speed peripheral controller (TUSB1000) targeted for test equipment, fax machines and printers. Samples are due later this year, and the device will be part of TI's cell library next year. The company is also readying power management and transient voltage suppressor parts to work with its recently announced four- and seven-port hubs (EN, Nov. 4), for a complete USB hub chipset.

NEC revealed it is working on a USB keyboard microcontroller and a USB printer chipset for 3Q97 release. The company currently has prototypes for hub and host controllers, due out in 1Q97, along with an ASIC core for full-speed peripheral devices.

Atmel showed a family of USB hub and peripheral devices that are currently sampling. The AT43311 four-port USB hub ASIC integrates analog cells with digital cells. "USB itself requires high-speed (48MHz) crystals, which are expensive and can cause incompatibility problems," commented product manager Daniel Tjoa. "We got around that by using an analog phase-locked loop (PLL), which allows us to use a cheap 6MHz crystal, which we multiply to 48MHz." The device also incorporates an overcurrent protection sensor. Samples of the AT43311 are expected to be available this month with production volumes slated for 1Q97.

Atmel also introduced the AT43351 MCU designed for low-speed joysticks, remote control units, mice and keyboards. The device uses flash memory to allow easy on-board modification as the USB specification evolves. Samples are slated to appear in January/February. A synthesizable USB function core for ASIC development is available from Atmel now (EN, Nov. 25). The core consists of the USB transceiver, the Serial Interface Engine (SIE) and the System Interface Logic.