Handheld games, voice, camcorders all point toward flash cards

Electronic News, Nov 16, 1998 by Samuel Nakhimovsky

Silicon Storage Technology

sunnyvale, calif.-The CompactFlash Association recently disclosed that the CompactFlash form factor is designed in over 100 different consumer platforms. The rapid rise of this flash card form factor can be attributed to the convenience of the IDE standard ATA interface that guarantees operability for all the host platforms using CompactFlash. This standard allows the same memory card to be used in a variety of platforms and applications, making it useful not only for today's products, but also for the consumer products of the future. In addition, with memory technology advances, CompactFlash cards will contain sufficient memory density not only for current, but also for next-generation consumer products.

Since the proliferation of Internet-enabled real-time exchange of information, individual consumers have discovered a convenient method to distribute photographs to their loved ones across the globe. The same consumers, while fascinated by the new digital technology, are not willing to accept lower image quality for their digital pictures. A typical 35mm 200 ASA film has a resolution of about 4,000x,4000 pixels. Currently, the higher-end consumer digital cameras only offer resolutions of 1,278x1,024 pixels. In the near future a 2,000x2,000 pixel (almost film quality) resolution digital camera will be within the average consumer's price range.

In order to achieve this image quality, many semiconductor companies have invested a significant number of resources into designing CCDs or CMOS sensors to capture the high-resolution image. Other companies are developing specific DSP-imaging ASICs to compress this huge stream of data into smaller and more manageable files. The same requirement is posed on the CompactFlash card-to be able to store large files, up to 12MBytes, conveniently and efficiently. A typical conventional roll of film stores 24 images. For an equivalent number of shots with an image quality similar to conventional film, a CompactFlash card needs to contain at least 200MB of memory and be able to write 12MB of memory in a few seconds. This memory density can be achieved in the CompactFlash form factor by early 2000 using 256Mbit flash memory technology with a multi-level cell memory structure.

The toughest requirement for CompactFlash cards will be to achieve at least 4Mbyte/sec. sustained-write throughput in order to keep the image storing process down to one second. For the future digital cameras to be equivalent to a conventional film camera, the image resolution will need to be 4 megapixels (2,000x2,000). With a high-quality (true color) 24bit A/D converter to digitize the image, a typical uncompressed file size can become as large as 12MB. With a 5:1 average fine quality compression, the typical high-resolution image file will be in the neighborhood of 2.4MB. The one-second write-specification is imposed by the consumer who will demand the set-up time between shots be no greater than a few seconds, a typical delay between shots in a conventional film camera. The CompactFlash card suppliers are researching innovative ways to achieve this high level of data transfer to flash media. Currently, the average CompactFlash card performance has been at 400KB/sec. Silicon Storage Technology, Inc., recently announced its highest performance CompactFlash card with sustained write performance of 1.4MB/sec.

With the digital still camera industry firmly embracing the CompactFlash card storage medium, the next logical expansion for flash memory cards will be into moving video. Current digital video cameras use magnetic tape to record video images. While magnetic tape is inexpensive, it is also bulky, causing digital video cameras to be physically large, susceptible to damage and difficult to duplicate. Besides, with a multitude of different formats such as VHS, Super VHS, 8mm cassettes, etc., film exchange is problematic.

A CompactFlash card format will enable much smaller digital video camera design, standardize the fragmented industry and offer superior reliability of recording. Since moving video consists of multiple still images, the memory demand for digital video recording will be substantially greater than that for still photography. Therefore, the acceptance of flash cards as a storage media for digital video imaging will greatly depend on the cost per megabyte of media storage. Using multilevel-cell flash memory architecture, future CompactFlash cards will be able to integrate large memory density affordably.

There are many other innovative consumer products being designed around the CompactFlash form factor. The newest generation of handheld PDAs, the PalmPilot look-alikes, built under Windows CE operating system, incorporate CompactFlash slots for memory expansion. To make these devices more portable, designers eliminated hard disk drive storage in favor of flash memory storage. The memory requirements of these new electronic gadgets exceed what could be easily integrated into the devices' Printed Circuit Board (PCB). With the data processing capabilities of these devices approaching conventional desktop computer systems, users will soon be able to perform tasks on the smaller PDAs similar to those on their desktops, such as creating Power Point presentations or developing extensive Excel spreadsheets.