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.
RF4CE TV
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.
FREESCALE
www.freescale.com
MICROCHIP
www.microchip.com
ZEROG WIRELESS
www.zerogwireless.com
ZIGBEE ALLIANCE
www.zigbee.com