Divio samples single-chip digicam device
eetimes.com
By Junko Yoshida
EE Times
(02/02/00, 12:22 p.m. EST)
SUNNYVALE, Calif. — Divio Inc. has introduced the NW820 single-chip imaging solution that can be used in digital still cameras or in video cameras with a Universal Serial Bus (USB) port.
The dual-mode chip "can function as an image compression/processing engine for both a USB-based desktop video camera when connected to a PC, and for a standalone digital still camera when detached from a PC," said Devang Patel, director of marketing at Divio, a fabless chip company based in Sunnyvale, Calif.
The chip integrates such functions as motion JPEG codec, image processing, auto exposure timing and sync generation.
The chip uses its motion JPEG engine to compress moving images on the fly, and streams desktop video over a standard USB connection at up to 30 frames per second.
The offering comes with a dynamic bit-rate control function, and adjusts its compression ratio depending on the available bandwidth on a USB at any given time, said Patel. The maximum 12-Mbit/second USB bandwidth usually needs to be shared with other peripheral devices such as a keyboard, joystick or speakers on a PC.
The company's motion JPEG codec, as well as its patent-pending image-processing and scaling technologies, make it possible to generate optimum video quality at higher frame rates, he said. While the chip typically compresses moving images in 352 x 288 Compact Image Format resolution, it is also capable of encoding video even in VGA resolution at up to 30 frames/second, Patel said.
PC gets the hand-off
However, when the chip is used in a desktop PC video camera, the task of video decoding must be handled by the host PC's CPU — at least a Pentium II running at 300 MHz or faster. In that case, it's the speed of the host CPU, and not the chip that determines the number of frames it can generate in decoding higher-resolution images, Patel said.
Meanwhile, when the chip is used in a standalone digital still camera, it can capture Web-ready 640 x 480 still images and decode them.
For OEMs interested in designing such a dual-mode camera, Patel said they will need, in addition to the NW820, an 8051 microcontroller, a bank of smart media NAND flash memory, a 1-Mbit x 16 SDRAM to hold images temporarily, a charge-coupled device (CCD) or CMOS sensor and a video encoder if the camera comes with a TV monitor to display pictures.
The chip features a glueless interface to all such components, as well as built-in USB interface support for off-the-shelf CCD and CMOS sensors. Powered via a USB port or external battery, it operates at 3.3 volts.
"Our chip is targeted for a digital camera market for teenagers — typically between 12 to 16 years old," Patel said. The chip is expected to be integrated into a $130 to $150 low-cost digital video/still camera, often manufactured by toy companies. It should enable teenagers to capture digital images, exchange them with friends or transmit them over the Internet, he said.
The NW820, priced at $10 to $15 in quantities of 100,000, is sampling now and is slated for volume production at the end of the second quarter. The chip is manufactured by Taiwan Semiconductor Manufacturing Co. using a 0.35-micron process.
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