Zigbee is moving to single-chip solutions that combine a Zigbee transceiver with a microcontroller. However, this does not give the flexibility that a two-chip solution provides. I’ll be taking a look at single-chip development kits in the future, but right now we examine three development kits from Ember, Silicon Labs, and Microchip.
Ember is a company targeting the Zigbee market with its own Zigbee transceiver while Silicon Labs and Microchip are microcontroller vendors. The design of the kits reflect this. For example, Ember’s kit is designed around a module that contains an Atmel Mega128L microcontroller and Ember’s EM2420 ZigBee chip suitable for deployment. The base board can support different modules because Ember provides single-chip solutions as well as support for other microcontrollers.
Silicon Labs’ and Microchip’s offerings are tied to their microcontrollers. Microchip’s board puts the ZigBee chip on a plug-in module that could, in theory, be used in a product but is really intended to provide designers with the ability to check out additional ZigBee chips. Silicon Labs has a single board designed to highlight one combination of chips.
One major implication about the offerings is based on the amount of time the vendors have been dealing with ZigBee. Ember’s offering is the most mature, since they were in on the ground level. Silicon Labs and Microchip waited for the standard and transceiver chip availability, so their offerings are not as polished.
Still, a developer’s choice will be dictated by a range of issues, including experience with the microcontroller. Likewise, most everyone’s experience with ZigBee will be minimal. So read on and see what may be the best fit for you.
Ember Development Kit
Ember’s QuickStart kit contains half a dozen sophisticated boards (see Fig. 1) making the kit rather expensive ($4995). It also comes with a pair of ZigBee stacks that are very mature and provide support for the range of ZigBee network configurations, including mesh support. It also comes with Ember Studio (see Fig. 2), a sophisticated Java-based diagnostic, programming, and network-management tool. If you are pushing the envelope on ZigBee flexibility, then put Ember at the top of your list.
The development boards are actually rather large but designed for use with a number of different configurations. This makes Ember’s offering one of the most flexible around. The base board has Ethernet support along with jumpers and connectors for development purposes, including a JTAG interface for the ZigBee module. The board supports two modules: a ZigBee module and a Rabbit Semiconductor RCM3400 with a Rabbit 3000 microcontroller. The latter is not the microcontroller that supports ZigBee. Rather, the Rabbit 3000 is used to program and manage the microcontroller on Ember’s ZigBee module.
This combination of modules and Ethernet has a number of implications that greatly simplify development. For example, it is possible to connect all the boards to an Ethernet network, which provides a very fast interface for reprogramming the ZigBee modules. This time can be significant when working with a large number of modules. Even half a dozen will be a lot. It is also possible to reprogram the ZigBee module even if the code in the module has a problem. Many kits require reprogramming on an individual module basis using JTAG or other debug interfaces. Finally, debugging a ZigBee network configuration problem is significantly easier if there is another way to get to the board. In this case, it is through Ethernet and the Rabbit Semiconductor module.