RF4CE And Other Wireless Tricks

Wireless design spans a wide range of technologies, including high-end software- defined radio, 802.11 Wi-Fi standards, and tiny 802.15.4-based systems that run off batteries for years or even scavenge power from local sources. Regardless of the technology, the resulting product must pass one or more RF-related approvals. In the U.S., designs must meet the standards of the Federal Communications Commission (FCC). The list of approval agencies gets longer when foreign destinations for the product are included.

One way around the cost and hassle of these approvals is to let someone else secure them. Developers often overlook key issues, especially in RF design, and pre-approved wireless modules can come in handy. For example, Microchip’s ZeroG WiFi is a small board with a ZeroG Wireless WiFi module (Fig. 1).

The module has two advantages. The first is a very fast design cycle for Microchip, since it’s just a board layout. Second, developers who put together a prototype using the board can do the same when laying out the final product. The module already has the required approvals, so developers do not need to get them again.

The cost of using modules can be significant. They cost more than the chips alone, even with the addition of bundled software protocol stacks. The trick is to know where the crossover point is when absorbing additional design and approval costs. Build 10, and modules are the obvious choice. The same is true when more than 100,000 devices are in play. Unfortunately, the boundary depends upon a number of factors, including the module and the module vendor.

The issue of wireless support is coming up more often for designers. Cellular and Wi-Fi communication are just a couple of examples. ZigBee is another.

ZigBee is based on the IEEE 802.15.4 standard. With the ZigBee RF4CE specification, the disadvantages of line-of-sight infrared remote controls goes away. The trick to remote controls is cost. Using a module is usually impractical, so designers can turn to development platforms like Freescale’s BeeKit (Fig. 2).

The BeeKit is typically used for software development. It can support a range of protocol stacks, including the ZigBee Pro-compatible BeeStack ZigBee, the RF4CE BeeStack Consumer, or Freescale’s own SynkroRF.

RF4CE could be widely adopted for TV remotes as well as other home control applications such as security and power management. It may also be something to include in your next product design.