Embedded Computing Design October 2011 : Page 11[Figure 2 | A typical OEM portable memory system consists of (1) a receptacle and (2) a memory key or token.] consumer memory device would likely become obsolete over the controllers’ lifespan. Portable memory applications that require rugged construction, a high mating cycle life, secure form factors, or long-term availability best exemplify when consumer memory devices should not be considered for embedded designs. Benefits of OEM portable memory In response to the unmet needs of many embedded systems, a less familiar cate-gory of portable memory devices – OEM portable memory – is emerging with a unique focus on OEMs. These devices provide the rugged construction, high mating cycle life, secure form factors, and long-term availability that consumer memory products do not deliver. Some portable memory manufacturers produce “industrial” versions of con-sumer memory products such as indus-trial CompactFlash cards or industrial SD cards. These so-called “industrial” devices might offer an extended tem-perature range, use slightly more robust materials, and support a higher number of write cycles. However, they still share many of the drawbacks associated with consumer memory devices: non-robust low cycle life connectors, non-secure form factors, potential obsolescence issues, and a lack of harsh environment ratings. For the purpose of this discussion, true OEM portable memory devices are defined as purpose-built systems that provide the following features. Unique form factors and controlled availability for baseline (physical) security OEM portable memory is most accu-rately described as a memory system as opposed to a singular device. Figure 2 shows an example of a typical OEM por-table memory system, which consists of a receptacle that integrates into a host system and a memory key or token that plugs into the mating receptacle. The token or key will only interface with its unique mating receptacle, which means OEMs only have to test and support one approved device. www.embedded-computing.com Figure 2 | A typical OEM portable memory system consists of (1) a receptacle and (2) a memory key or token. Figure 3 | A memory token with solid over-molded construction can meet harsh environmental requirements. Additionally, unique form factors prevent most unauthorized data transfers, help protect the host system from malicious files, and provide a new potential rev-enue stream when an OEM becomes the exclusive source of new/replacement keys or tokens. Truly rugged construction for harsh environments and long-lasting designs Truly rugged portable memory can withstand extreme temperatures, rough use, sterilization, chemical exposure, static electricity, dust, dirt, moisture, shock, and vibration. To meet these harsh envi-ronmental requirements, some manufac-turers use a solid over-molding process that encases the electronic components in specially engineered composite plastic materials (see Figure 3). [Figure 3 | A memory token with solid over-molded construction can meet harsh environmental requirements.] receptacle is also protected. Receptacles in OEM memory systems should also carry ratings consistent with the harsh environments in which they will operate, including IP ratings such as IP65 or IP67 or military environmental ratings such as MIL-STD-810. These environmental ratings allow OEM memory systems to operate in harsh environments where con-sumer memory devices would not survive. High mating cycle life OEM memory systems offer a higher number of mating cycles than consumer memory devices, ranging from 50,000 cycles to 200,000 cycles for certain OEM receptacles. For example, an OEM memory receptacle rated at 50,000 inser-tion cycles would last a minimum of 13.5 years if used 10 times per day. To put that into perspective, a typical USB connector rated at 1,500 insertion cycles that sees the same 10 insertions per day October 2011 | 11 The environmental capabilities of portable memory devices do little good unless the Embedded Computing Design Publication List |
