Chip & IP vendors get behind USB on-the-go

Chip vendors get behind USB on-the-go
By Anthony Cataldo and Yoshiko Hara, EE Times
June 10, 2002 (5:29 p.m. EST)
URL: http://www.eetimes.com/story/OEG20020610S0075

SAN MATEO, Calif. — Several chip and intellectual-property suppliers have promised to deliver by the second half of the year silicon that will support the newly minted USB on-the-go specification, which will allow mobile gear and peripherals to be connected without going through a PC.

ARC International and Seiko Epson Corp. promise delivery soon of USB on-the-go (OTG) silicon to meet what they call pent-up demand from mobile phone and peripheral-device makers for the point-to-point communications standard.

Their announcements come a month after TransDimension Inc. said it was shipping its single-chip OTG243 on-the-go controller to manufacturers of cellular phones, PDAs and MP3 players. Cypress Semiconductor Corp. has said that it intends to field an on-the-go USB device later this year.

"It's not easy for cellular phones to connect to other peripherals," said Tatsuo Asada, who manages strategic IC product planning in Epson's semicond uctor division. "With the USB OTG supplement, the situation will drastically change."

Full-service platform

ARC's USB 2.0 solution, which was been groomed for the point-to-point communications spec, includes a host controller, configurable RISC processor core and software package. Slated for August introduction, the USB Now platform marks ARC's shift from processor IP house to full-service platform provider, said Michael Gulett, the U.K. company's chief operating officer.

"Previously, at least three or four IP suppliers would be needed," Gulett said. "USB on-the-go is growing quite significantly by the usage of USB in portable handheld devices where you don't need a PC as a host."

ARC has been eyeing USB since its 2000 acquisition of VAutomation Inc., a developer of USB devices. The company also helped define the USB on-the-go specification, a subset of USB 2.0 that was ratified last December.

The platform's USB controller acts like a media-access controller that drives a phy sical-layer transceiver. The ARCtangent processor, meanwhile, handles the USB packets from the controller, though non-ARC CPUs can also be used. This kind of partitioning means the USB controller can do without large buffers, saving some 100,000 gates of silicon area, ARC said.

Typically, the USB software stack consumes less than 1 percent of the ARCtangent's horsepower. That frees the processor to handle system-level tasks like interrupt management and some heavy lifting like digital signal processing. An MP3 player using this approach, for example, could connect directly to a pair of speakers and decode the audio signals, said Brian Machesney, director of marketing for ARC.

To increase data throughput, ARC has added a direct memory access (DMA) engine that can autonomously transfer data to and from the host. ARC said it can reach the fastest, 480-Mbit/second, data transfer rate for the on-the-go spec, and hopes to convince others that it won't necessarily draw excessive power.

"There has been a lot of concern in the USB community about the power consumption in 480 Mbits/s, but our analysis shows that to transfer the same amount of data you take less energy transferring at the higher speed," Machesney said.

Meanwhile, Japan's Seiko Epson has developed a one-chip USB on-the-go controller, which is expected to find a place in mobile phones. Epson plans to begin volume production in September at 100,000 units a month, ramping to 500,000 a month by December. Sample pricing will be about $12.

"We believe that our OTG controller LSI is the first single-chip solution in Japan and the second in the world market. We expect that competitors' products will become available in the fourth quarter," said Yasuhide Fujiwara, general manager of Epson's chip marketing and promotion division.

Dubbed the SIR72005, this single-chip controller integrates USB host function, peripherals and on-the-go functions to let two devices communicate point-to-point, without a PC middleman.

It is fabricated in 0.25- micron CMOS, and operates at 3.3 volts at the I/O and 2.5 V internally. Housed in a 64-pin quad flat pack or 81-pin chip-scale package, it supports speeds to 12-Mbits/second.

The device is billed as suitable for mobile phones, PDAs, digital cameras, camcorders, storage devices and printers. With USB on-the-go, mobile phones will be able to exchange telephone directories, images or music files and will also be capable of communicating with peripherals like printers, storage devices, game controllers and speakers, the company said.

Epson officials said USB on-the-go will compete with IEEE 1394 and Bluetooth, especially in handheld applications. "OTG High Speed and IEEE 1394 at 400 Mbits/s are fast but not suitable for mobile communication in terms of power consumption. Bluetooth at 1 Mbit/s is too slow. OTG full speed is most suitable for mobile-gear communication," said Hideki Takei, general manager of the chip design department in Epson's semiconductor operations division.

"We put the priority on low power consumption and light load on the host system CPU when we designed the S1R-72005," Takei said. Though he did not disclose how much power the device consumes, he said that the IEEE 1394 technology "is several times" more power hungry than OTG at full speed.

The S1R72005 evaluation board contains the S1R72005 device, CPU, RAM, ROM to store test data and a receptacle for the USB Mini-A plug. An Epson color printer with USB 1.0 interface, now on the market at a volume-sale price, prints data directly sent from the board through a commercially available cable with the Mini-A plug and a standard USB-B plug.