Modules Make The World Go Around

July 9, 2009

Need to get a project done quickly? Modules can save time and money, especially when you’re working with wireless technologies. They often provide a family of solutions for upgrading a system with a single platform. Modules can be tiny

William G. Wong

Modules can be tiny but pack a punch. The Gumstix Overo Fireo puts more on a gumstick-size circuit board than many larger systems (Fig. 1). It includes a 600-MHz OMAP 3530 processor from Freescale with a Cortex-A8 processor and a C64x+ DSP. The board has 256 Mbytes of flash, 256 Mbytes of RAM, Bluetooth, 802.11g, and an SD card slot. A pair of high-density sockets provides access to most peripheral interfaces.

Micro/sys offers an array of tiny StackableUSB modules including a host of hosts, from 8-bit micros to x86 processors (Fig. 2). They work in a stack or connected to a PC or laptop. Embedded USB is more common, but communication standards are still lacking (see “Embedded USB Tower Of Babel”).

SYSTEM MODULES The processor complex often is the hardest thing to design, especially as highspeed interfaces like PCI Express come into play. Adlink’s Express-ATC COM Express Type 2 provides a standard platform with a 1.6-GHz Atom, three 1x PCI Express connections, SATA, Gigabit Ethernet, high-resolution video, and even a 4-Gbyte flash drive (Fig. 3).

Standard platforms such as AdvancedTCA, VME, VPX, and CompactPCI sport a range of standard headers and connectors for modules like Curtiss-Wright Controls Embedded Computing’s ADC513 FPGA mezzanine card. Its pair of National Semiconductor two-channel, 8-bit analogto- digital converters (ADCs) runs up to 1 Gsample/s. The FPGA is found on the host board (Fig. 4).

WIRELESS MODULES Wireless modules are a good choice for a variety of reasons, from addressing complex antenna issues to obtaining Federal Communications Commission (FCC) approval. RF design is the forte of few designers, though modules make shortwave simple.

The Linx Technologies GPS provides high-gain, low-noise performance with on-board antennas (Fig. 5). Just solder the surfce-mount device (SMD) package to the host board, and you’re ready to read the position of the device.

Adding 802.15.4 or ZigBee support is just as easy using Atmel’s ZigBit modules (Fig. 6). High-performance units can provide line-of-sight links up to 4000 m. Smaller units run up to 1000 m but only draw 6 µA in sleep mode. Best of all, they already have FCC approvals. No additional work is necessary.

M2M MODULES Machine-to-machine (M2M) is often a secondary design issue, so self-contained packages like pluggable ConnectOne’s wired/Wi-Fi solutions (Fig. 7) or Lantronix’s MatchPort b/g Pros Wi-Fi module (Fig. 8) are the way to go. They have a simple serial interface and can operate with or without a host.

Most modules of this type use a simple serial interface and provide access to a plethora of Internet communication protocols, including secure linkage and roaming options not found in basic Wi-Fi stacks. Overall, the biggest challenge for designers is picking the right module from a wide range of options.