Echelon LonTal Stack - Manual (Page 16)

4 Introduction to the LonTalk Stack
A L ON W ORKS device that uses a single processor chip is called a Neuron-hosted
device, which means that the Neuron-based processor (the Echelon Smart
Transceiver) runs both the application and the LonTalk protocol.
For a Neuron-hosted device that uses a Neuron Chip or Echelon Smart
Transceiver, the physical layer (layer 1) is handled by the Neuron Chip or
Echelon Smart Transceiver. The middle layers (layers 2 through 6) are handled
by the Neuron firmware. The application layer (layer 7) is handled by your
Neuron C application program. You can create the application program using the
Neuron C programming language in either the NodeBuilder ® FX Development
Tool or the Mini FX.
A L
ON
W
ORKS
Device with Two Processor Chips
Some L ON W ORKS devices run applications that require more memory or
processing capabilities than a single Neuron Chip or Echelon Smart Transceiver
can provide. Other L ON W ORKS devices are implemented by adding a transceiver
to an existing processor and application. For these applications, the device uses
two processor chips working together:
• An Echelon Smart Transceiver or Neuron Chip.
• A microprocessor, microcontroller, or embedded processor. This is
typically called the host processor.
A L ON W ORKS device that uses two processor chips is called a host-based device,
which means that the device includes an Echelon Smart Transceiver or Neuron
Chip plus a host processor.
Compared to the single-chip device, the Echelon Smart Transceiver or Neuron
Chip implements only a subset of the LonTalk protocol layers. The host
processor implements the remaining layers and runs the device’s application
program. The Echelon Smart Transceiver or Neuron Chip and the host processor
communicate with each other through a link-layer interface.
For a single-chip, Neuron-hosted, device you write the application program in
Neuron C. For a host-based device, you write the application program in ANSI C,
C++, or other high-level language, using a common application framework and
application programming interface (API). This API is called the LonTalk API. In
addition, for a host-based device, you select a suitable host processor and use the
host processor’s application development environment, rather than the
NodeBuilder FX Development Tool or the Mini FX application, to develop the
application.
Echelon provides the following solutions for creating host-based L ON W ORKS
devices:
• ShortStack Developer’s Kit
• LonTalk Stack Developer’s Kit
ShortStack Developer’s Kit
The ShortStack Developer’s Kit is a set of development tools, APIs, and firmware
for developing host-based L
ON
W
ORKS
devices that use the LonTalk Compact API
and a ShortStack Micro Server.