Open the Source Code (Rev 1.1)

Many RF technologies are competing on 2.4GHz. The WLAN and Bluetooth have dominated the consumer wireless market. Zigbee is getting hotter in the mesh network application as well. More and more chip vendors have released their new products for Zigbee. TI/Chipcon, Freescale, Microchip, Atmel, Slilabs and Amber are active in Zigbee market. Zigbee is a wireless mesh network; its initial investment is much higher than an individual microcontroller based application. A serious development on a Zigbee project must include ICs, the Zigbee stack, the application software in the network nodes and the network administration software for the control terminals.

In September 2007, TI announced that it would offer its fully functional Zigbee stack, Z-stack to the developers free of charge. Every registered developer can download the source code from the web site. It was a shock to this market. Before this open source promotion, the quotation of this certificated Z-Stack was 100K USD.

Z-Stack can be downloaded in two formats: a "core" stack installer or a "full" stack installer. The "core" installer is targeted to experienced Z-Stack users who only need updated library and source files. The "full" installer is intended for users who would like additional application examples.

Z-Stack has two releases. One release is Zigbee 2007 (Zigbee PRO), which is available for CC2520+MSP430 microcontroller. The other release is Zigbee 2006, which supports CC2420+MSP430 microcontroller and 80C51 based SoC CC2430/2431. IAR C/C++ is the preferred compiler for both releases. The developer can download 30-day IAR compiler for free of charge. It is a fully functional compiler. A 30-day evaluation license for the Sensor Network Analyzer from Daintree is available to new users. In order to use the Daintree Sensor Network Analyzer (SNA) software, a packet sniffer compliant hardware module is needed. the SNA software works with hardware included in the CC2520DK, CC2430(Z)DK, and CC2431(Z)DK.

TI and its partners have offered everything for free of charge, at least in 30 days. As a result, you can simply order a Zigbee starter kit and start the project.

Here I must correct my description for TI's Z-stack offering. The Z-stack is freely available, but it is not an open source project. The Zigbee stack is deliveried in form of libraries. In Z-stack, there are some source files in the name of MAC. But these files are not MAC component, but a "glue" driver to hook the library and user application software. Since it is a library, it is hard to use another compiler and port to another architecture. If you just want to develop your own application code, the Z-stack is good.

As same as TI, Microchip also offers its free downloadable Zigbee stack on its site. This Zigbee stack has three versions for PIC18, PIC24 and dsPIC33. I inspected the code. The software from Microchip is much simpler than the counterpart from TI, and with some limitations. However, the source seems fully opened. Obviously, TI's stack is much better than Microchip's. At least TI claims its Z-stack is certificated.

Thanks to Akiba's feedback, here I offers a link to its his open source blog.

Freaklabs, open source Zigbee blog by Akiba, with open source Zigbee project: FreakZ.

Zigbee is not popular enough, why?

The ecosystem of Zigbee is different than Bluetooth. Most of the Bluetooth products are consumer electronics. The application profiles are well defined. These Bluetooth devices have been tested and certificated for interoperability. The Zigbee products are designed for the industrial or business applications, from AMR/AMI to access control. The application profiles of Zigbee have not been defined as well as Bluetooth SIG did. Most of the customers of Zigbee are the system integrators for certain projects, instead of the consumer electronics manufacturers for Bluetooth. These SIs only care about if their project can run or not, rather than the device interoperability.

A fully functional Zigbee requires 40KB ROM in the 8-bit microcontrollers. Actually some of these projects are using proprietary protocols, which only take about 4KB ROM. All of the silicon suppliers are also offering proprietary RF protocols as alternative solutions. TI has SimpliciTI, and Microchip has MiWi, and Amber and Freescale have their own protocols. Obviously, some of the wireless applications need extreme low cost P2P protocol to reduce the BOM cost. The CE giant, SONY uses Freescale' Zigbee as RF remote control for its LCD TVs. They did not use the standard Zigbee protocol. Of course, a simple P2P protocol is good enough for a TV set. The legacy consumer IR remote control is even a one-way communication product.

If there are no standard products in the market, how can Zigbee be popular? Up to now, the most promising Zigbee application is AMR, the metering market. The mesh network can not be widely deployed in the home. Home automation is not a big market. The X-10 has proved this point for years. Zigbee can only be deployed in building automation, security surveillance systems and RFID systems in offices and workshops. The mesh network is too complex for the consumer electronics.

After all, now Zigbee is available for every system integrators. The development effort and investment are reduced because of the open source stack and free tools. More and more features including OTA download, voice message and static picture delivery have been demonstrated on Zigbee. You can unleash yourself in wireless applications. They free the source, you free yourself.

Read the Italian version: Lo stack zigbee open source