Instrumentation • Electronics
Fig. 1. Nexus GB has supplied data keys to Bambardier as part of a project to help monitor and manager the location of trains on the track.
4 Victoria James explains that choosing consumer focused portable memory can be a big mistake. Here she provides a series of guidelines to follow when choosing portable memory devices for use in embedded systems.
4 Victoria James explique que choisir une mémoire portable focalisée sur le consommateur peut se révéler être une erreur. Elle propose ici une série conseils à suivre lors du choix d’un outil de mémoire portable pour l’utilisation dans les systèmes intégrés.
4 Victoria James erklärt, warum die Wahl von Speichermedien, die für Konsumenten entwickelt wurden, ein großer Fehler sein kann. Sie präsentiert eine Reihe von Richtlinien, die bei der Wahl von tragbaren Speichermedien für die Verwendung in eingebetteten Systemen beachtet werden sollten.
Choose portable memory for embedded systems
W
hile most embedded system components are sourced from OEM focused manufacturers, portable memory devices are a grey area. The high-
volume consumer electronics market is estimated at £129billion
annually.This creates significant demand for USB flash drives, SD cards and other consumer-focused portable memory devices and for embedded system designers the economies of scale these devices offer can be appealing. Manufacturers of consumer memory devices are
primarily focused on the needs of the fast-changing consumer electronics market and this doesn’t suit the design engineer. In response, a lesser-known category of OEM focused portable memory systems is providing alternatives that meet requirements unique to non-consumer embedded designs. These two categories of portable memory
devices offer unique advantages and disadvantages. The most important thing for engineers though, is how the two categories perform when integrated into embedded designs in commercial, industrial, government, military, medical and other demanding OEM environments. Typical applications for portable memory in embedded systems include access control and rights
management, usage monitoring, data logging, in-field firmware updates and product authentication. The environmental factors and typical usage of the system influence which kind of portable memory solution is the best fit for the application.
Consumer memory
As a result, the potential design considerations for portable memory systems are extensive, ranging from the communications interface/protocol, connector durability, cost and data throughput speed to product life cycle and ruggedness. Some of these design considerations may be
mutually exclusive. For example, small size typically precludes rugged construction. Prioritising these design considerations makes it easier to determine which features are most important for a particular application. In addition to SD cards and USB flash drives,
other consumer memory devices used in OEM designs may include SDHC, microSD and CompactFlash cards. While these NAND-flash- based devices are primarily designed for PCs laptops, digital cameras, mobile phones and MP3 players, the principal benefits that are intended for consumer electronics can also apply to non- consumer embedded devices:
www.engineerlive.com 21
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68