Tech Primer
ZigBee is an IEEE 802.15.4-compliant technology used to build mesh networks for general purposes with low-cost and self-management function. This technology is prevalent in areas like home and building automation, smart power supply, and health care. For more details about ZigBee, please refer to the technology introduction on element14 website by clicking:
http://www.element-14.com/community/docs/DOC-13585
The coordinator (FFD – Full Function Device), router (FFD) and end devices (FFD or RFD – Reduced Function Devices) are three key devices in a ZigBee network. Only coordinator can start and manage a network. It provides address table service, maintains binding between devices, and saves messages before delivery. Router routes messages, assigns a block of addresses given by coordinator, and allows other devices connect to its own network. End devices can only scan and find a single device (router or coordinator) and then connect to it. The group of devices on the right part of the figure shows the topology of ZigBee mesh network. In order to communicate with external networks, an Ethernet or a GSM protocol has to be enabled in coordinator. As a result, this device is also called ZigBee gateway through which we can send or receive message or command remotely.
Theoretically a ZigBee gateway solution need to use a high-performance microcontroller to implement both TCP/IP and ZigBee protocol stacks, or GSM/GPRS and ZigBee protocol stacks. In practice, we usually use ZigBee SoC (for example Texas Instruments CC2430, Freescale’s MC13224 and Jennic’s JN5148 to reduce the OEM time to market.
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