Philips Semiconductors is hoping to liberate peripheral devices from the PC by extending the use of USB into embedded systems.
The chip division of Philips Electronics N.V. today will unveil a single-chip controller that allows a universal serial bus peripheral, such as a PDA or digital still camera, to simultaneously act as a USB host.
For example, a PDA that today connects with a PC to synchronize data in the future can interface directly to a printer, CD-ROM, or other Internet appliance, said Tee Chee Yen, technical marketing manager for USB products at Philips, Sunnyvale, Calif.
The idea is similar to what is being promoted by backers of FireWire for such high-speed peripherals as professional audio and video equipment. USB will enable a FireWire-like connection in everyday consumer devices like set-top boxes, MP3 players, or game consoles, and as the USB standard evolves to faster bus speeds, the interface may even compete with FireWire, Tee said.
"Some OEMs have been envisioning a USB host function on things like cameras for a long time, but there was no chip to enable it," he said.
USB host-controller functions are typically built into the "glue" chipsets that connect a microprocessor to all of the PC's subsystems, such as memory, storage, graphics, or communications, Tee said. But these chipsets are not easily designed into peripherals or Internet appliances that are built around RISC processors.
The ISP1161 and ISP1162 chips will allow embedded systems to operate as a stand-alone USB host, an interface device, or both simultaneously, simply by reconfiguring the software, according to the company. Each chip's generic 16- or 32-bit parallel I/O and direct memory access (DMA) interface circuitry simplify the connection to most RISC, DSP, and microcontroller devices on the market, the company said.
The potential market for a USB host function in embedded systems is significant. In Japan, where digital cameras are popular, Philips estimates the market at about 1 million units per month. Chips sold into set-top boxes in Europe could number 500,000 a month. In the United States, PDAs may consume 1 million to 2 million units per month, according to the company.
So far, Philips may share this total available market with only one other chip supplier.
ScanLogic, Burlington, Mass., this spring began sampling a pair of similar devices, a single- and dual-port USB master/slave combination chip.
Either offering's success will depend on the uptake of USB outside conventional PC peripherals; however, the ubiquity of USB in PCs today almost ensures its acceptance in the embedded space, Tee said.
"USB's popularity in PCs is driving down cost, so it's much cheaper than FireWire," he said. "I believe USB will be the dominant bus for PCs, and will be successful in replacing FireWire in embedded systems as well."
The company's ISP1161 and ISP1162 conform to the USB 1.1 specification for the host and device function, but diverge slightly by customizing the controller's interface to the system processor to eliminate PCI-interface overhead associated with the traditional OpenHCI host-controller specification.
The devices adopt the core of Philips' original peripheral controller, the ISP1181, which has 16 configurable end points to allow for interrupt, bulk, control, and isochronous USB transfers; a parallel interface of 1.11 Mbytes/s or 90-ns read/write cycles; 16-bit parallel I/O ports; and local DMA transfer support.
The chips also build in low-power circuitry to enable compliance with ACPI, OnNow, and USB power-management requirements.
The company's Networking Software group offers the host stack for the ISP1162/2, supporting a range of real-time operating systems.
Philips will demonstrate the ISP1161 in mouse and keyboard implementations at the Intel Developer Forum in San Jose on Aug. 17. Samples of the chip, which supports the USB 1.1 specification and a 16-bit data bus, will be available in August. Housed in a 64-pin LQFP, pricing will be $4.90 in 10,000s.
The ISP1162, supporting USB 2.0 and a 32-bit bus, is slated to sample in the fourth quarter. In an 80-pin LQFP, pricing will be $5.30 in similar quantities. Evaluation kits for both devices will also be available.