In order to achieve economical and standardized deployment, Echelon designed the Neuron Chip. The Neuron name was chosen to point out the similarities between proper network control implementation and the human brain. There is no central point of control in the brain. Millions of neurons are networked together, each providing information to others through numerous paths. Each neuron is typically dedicated to a particular function, but loss of any one does not necessarily affect the overall performance of the network.
To the developer and the integrator, the beauty of the Neuron Chip lies in its completeness. The built-in communication protocol and processors removes the need for any development or programming in these areas. To refer back to the ISO/OSI reference model of a communication protocol, the Neuron Chip provides the first 6 layers. Only the application layer programming and configuration needs to be provided. This standardizes implementation and makes development and configuration relatively easy.
Most LonWorks devices take advantage of the functions of the Neuron Chip and use it as the control processor. The Neuron Chip is a semiconductor device specifically designed for providing intelligence and networking capabilities to low-cost control devices. The Neuron Chip includes three processors that provide both communication and application processing capabilities. The device manufacturer provides application code to run on the Neuron Chip and I/O devices to be connected to the Neuron Chip. Echelon Corporation designed the original Neuron Chip, and successor members of the family now designed and manufactured by Echelon’s manufacturing partners. Cypress Semiconductor and Toshiba are all current producers of Neuron Chips. Multiple suppliers create a competitive environment for the Neuron Chips, provide reliable sources for the chips, and help drive prices down.
The Neuron Chip is a system-on-a-chip with multiple processors, read-write and read-only memory (RAM and ROM), and communication and I/O subsystems. The read-only memory contains an operating system, the LonWorks protocol, and an I/O function library. The chip has non-volatile memory for configuration data and for the application program, both of which are downloaded over the LonWorks network. At the time of manufacture, each Neuron Chip is given a permanent unique-in-all-the-world 48-bit code, called the Neuron ID. A large family of Neuron Chips is available with differing speeds, memory type and capacity, and interfaces. Approximately 54 million Neuron Chips had been shipped as of mid 2004.
A complete operating system including an implementation of the LonWorks protocol, called Neuron Chip Firmware, is contained in ROM on, or attached to, every Neuron Chip. Most LonWorks devices include a Neuron Chip, which has an identical, embedded implementation of the LonWorks protocol. This approach eliminates the “99% compatibility” problem and assures that connecting LonWorks devices together on the same network requires little or no additional hardware. The Neuron Chip is actually three, 8-bit inline processors in one. Two execute the LonWorks protocol; the third is for the device’s application. The chip is, therefore, both a network communications processor and an application processor, significantly reducing the implementation cost for most LonWorks devices.