Echelon FTXL - Manual (Page 17)

FTXL User’s Guide 5
Compared to the single-chip device, the Smart Transceiver implements only a
subset of the LonTalk protocol layers. The host processor implements the
remaining layers and runs the device’s application program. The Smart
Transceiver 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 Development Tool or the Mini EVK application, to develop the
application.
Echelon provides the following solutions for creating host-based L ON W ORKS
devices:
• The LonTalk Platform for ShortStack Micro Servers
• The LonTalk Platform for FTXL Transceivers
LonTalk Platform for ShortStack Micro
Servers
The LonTalk Platform for ShortStack Micro Servers 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.
A ShortStack Micro Server is a Smart Transceiver with firmware, the
ShortStack
firmware , that implements layers 2 to 5 (and part of layer 6) of the LonTalk
protocol, as shown in Figure 2 on page 6. The host processor implements the
application layer (layer 7) and part of the presentation layer (layer 6).
The ShortStack firmware allows you to use almost any host processor for your
device’s application and I/O. The Smart Transceiver implements layers 2 to 5
(and part of layer 6) of the LonTalk protocol and provides the physical interface
for the L
ON
W
ORKS
communications channel.
A simple serial communications interface provides communications between the
ShortStack Micro Server and the host processor. Because a ShortStack Micro
Server can work with any host processor, you must provide the serial driver
implementation, although Echelon does provide the serial driver API and an
example driver for some host processors. Currently, example drivers are
available for an Atmel ® ARM7 microprocessor and an Altera Nios II embedded
processor.
For ShortStack device development, you use the C programming language 1 . You
use the Echelon LonTalk Interface Developer utility to create the application
framework. Your application uses an ANSI C API, the Echelon LonTalk
Compact API, to manage communications with the ShortStack Micro Server and
devices on the L ON W ORKS network.
1 For ShortStack device development, you could alternatively use any programming language
supported by the host processor if you port the LonTalk Compact API and the application framework
generated by the LonTalk Interface Developer utility to that language.