Electronic Design

Ultra-Mobile PCs Become A "Hotspot" In Portable Electronics

Computing, connectivity, and keyboards form the foundation of the burgeoning UMPC consumer market.

It's no secret that compact, lightweight laptops have seen meteoric rises in popularity and functionality. The same can be said for portable computing platforms like the RIM Blackberry and the Treo 700w (see "Powerful Portables"). Now, the latest ultra-mobile PCs (UMPCs), such as Hanbit's Pepper Pad, are taking advantage of the new lightweight, low-power technology to deliver PC-level functionality in a handheld device (Fig. 1).

It's been more than 10 years since Zenith released the 3.2-lb CruisePad. It had limited wireless support, but came long before there were hotspots in every corner coffee shop. The CruisePad also was on the cusp of the Internet, yet it was a device in search of a market. Since then, tablet PCs have found success in a number of vertical markets, but they haven't made a significant dent in the consumer market for two reasons: price and power. That may soon change, however, as prices continue to fall and demand for low-power, high-performance computing platforms—for technology like smart phones and laptops—grows.

ARM and its licensees made quite a bit of money taking advantage of low-power 32-bit architectures. But x86 architectures, which are popular in PC-style applications, are hitting low-power targets as well. AMD's Geode and VIA Technologies' C7-M can be found in many of the UMPC platforms. Samsung almost doubled the battery life with its switch to the C7M for its Q1B UMPC (Fig. 2). Hardware acceleration to support services such as multimedia codecs are critical to delivering content as well as reducing power consumption.

Storage devices such as Seagate's 1.8-in. Lyrion hard drives pack 60 Gbytes of data sufficient for video streaming (Fig. 3). The move to hybrid drives mixes low-power, high-capacity NAND flash with higher-capacity magnetic media (see "Hybrid Drive Blends Flash And Magnetic Technologies,"). The scores of units being shipped target portable MP3 and video players like Apple's iPod.

Though compute power and storage statistics keep changing, sufficient performance and capability have been available for quite some time. What's been missing is low-cost, high-performance communication. The latest UMPCs sport 802.11b/g and Bluetooth support for access to the Internet, Internet Protocol TV (IPTV), Voice over Internet Protocol (VoIP), and a host of other communication services. Bluetooth provides access to wireless headsets, keyboards, and mice. Wireless communication can even connect these devices to portable projectors.

The importance of wireless and USB can't be understated. They eliminate the plethora of specialized connectors and power-hungry interfaces. The lack of additional hardware also reduces weight. The downside is power consumption. In fact, wireless and screen power consumption now exceed the processor's power consumption, which was initially the major power hog.

More efficient wireless support and the use of power cycling will help, though power cycling can't be used in streaming multimedia environments that require continuous connections. Wireless Wi-Fi support appears in a range of devices, including SanDisk's Sansa Connect (Fig. 4) and Microsoft's Zune (Fig. 5). The Zune uses Freescale's i.MX31, which incorporates a 533-MHz ARM11 processor.

The main power consumer for LCD displays tends to be the backlight. New light-source alternatives such LEDs will help. Even so, power continues to be the bane of all portable devices.

Thankfully, many of the new peripheral additions to portable devices aren't power drains. Digital cameras and fingerprint readers are just two of the options popping up on UMPCs.

The cell-phone industry is the main driver of low-power, low-cost camera chips. Their resolution tends to lag the clarity of dedicated digital cameras because cellphone cameras typically match the display resolution. UMPCs, on the other hand, typically have higher-resolution screens and more storage capacity, but most will often use existing camera chips.

These compute platforms and storage capacities exceed that of most laptops from only a couple of years ago. It isn't surprising, then, to find tiny clamshell portables like FlipStart running a stock version of Windows XP (Fig. 6).

The display size for UMPCs is typically on the order of 800 by 480 pixels—ideal for watching movies and enough resolution for detailed presentations. The FlipStart's resolution of 1024 by 600 falls just short of the usual 1024 by 768. It also has a small 5.6-in. screen, making resolution more important. In all cases, these screens are significantly larger and have higher resolution than cell phones or other handheld devices (e.g., Palm's Tungsten E2).

Systems such as Pepper Pad incorporate small keyboards. These systems are suitable for scanning and answering email, but not for writing the great American novel. Microsoft includes an application called DialKeys that puts up a pair of semi-circular, semitransparent areas on the outer edges of the touch-sensitive display. Higher-performance display chips and the higher screen resolution make transparency easy to employ.

The orientation permits thumb-typing, like on the Pepper Pad. However, the sensation is much different because of the lack of tactile feedback. I had a chance to use DialKeys on the Samsung Q1B. It works and is quite usable after a little practice.

The biggest problems surrounding the UMPC are a consistent use of applications designed for a larger screen and full keyboard, as well as those few applications designed specifically for the UMPC. Developers need to take a cue from GPS navigation systems, where fingers and simplicity matter. Embedded developers have the advantage of being able to customize applications in this fashion.

UMPCs are no longer a solution in search of a problem. The host of growing consumer markets includes video playback and Web browsing. Key challenges no longer involve hardware issues (e.g., battery life); rather, it's all about software and legal difficulties.

For example, now that ripping and downloading MP3 files has become commercially viable, video players need a data source. Moves to drop onerous copy protection, such as that proposed in the Apple and EMI agreement, is a step in that direction.

Many vertical markets are emerging as the prices of these systems decline. Point-of-sale systems, home-management control panels, and medical presentation and analysis are just a few. These markets benefit from features like fingerprint readers to provide a higher level of security necessary in these environments. Other applications, such as inventory control, are helped by additions such as barcode or RFID scanners.

Finally, there's the issue of price. For many consumer applications, the sweetspot is in the $200 to $500 range.

Flash-based solutions address the low end. These price points are easily attained using off-the-shelf parts, making these platforms ideal for custom embedded designs as well as general-purpose systems. While they aren't replacing laptop and desktop systems, UMPCs are a good complement to such systems as well as excellent platforms for standalone applications.

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