NXP Semiconductors JN516x-EK001, Руководство пользователя, Страница: 41 / 86

JN516x-EK001 Evaluation Kit
User Guide
JN-UG-3093 v1.5 © NXP Laboratories UK 2015 41
2.5 Wireless Network Protocol Stack
The software which runs on a wireless network node deals with both application-
specific tasks (e.g. temperature measurement) and networking tasks (e.g. assembling
a message to send to another node). The software on a node is organised as a
number of layers, forming a stack, with the user application at the top. The basic layers
of a wireless network protocol stack are typically as illustrated in
Figure 31 below.
The stack layers are outlined below, from top to bottom:

Application layer: Contains the user applications which run on the network
node and provides an interface to the lower layers

Network layer: Provides the networking functionality and an interface to the
IEEE 802.15.4 layers (see below) - for example, this layer could be provided by
the ZigBee PRO protocol, but is not required for a pure IEEE 802.15.4 network

Data Link layer: Provided by the MAC (Media Access Control) layer of the
IEEE 802.15.4 standard, and responsible for message assembly/disassembly
and addressing (e.g. specifying the destination of outgoing messages)

Physical layer: Provided by the PHY (Physical) layer of the IEEE 802.15.4
standard and concerned with interfacing to the physical transmission medium
(radio, in this case)
A number of C APIs (Application Programming Interfaces) are provided to allow a user
application to easily interact with the layers of the stack. The required APIs depend on
the protocol used (IEEE 802.15.4, JenNet-IP, ZigBee PRO or ZigBee RF4CE) and are
supplied in the relevant NXP Software Developer’s Kit (SDK) - see
Section 4.1 .
The software components that implement the Data Link and Physical layers of the
stack are pre-programmed in on-chip ROM. The user application is developed and
built on a PC. The resulting application binary file also incorporates the Network layer
of the stack and is loaded into the Flash memory of the node.
In order to use the JenNet-IP Smart Home Demonstration which is pre-loaded in the
JN516x-EK001 Evaluation Kit boards, no knowledge of the JenNet-IP software is
required. However, you should familiarise yourself with the software for your chosen
protocol before starting your own application development - refer to
Section 4.3 for
details of the user documentation for the different protocols.
Figure 31: Basic Layers of Stack
Data Link layer
Network layer
Application layer
Physical layer