Echelon Neuron C - Manual (Page 203)

Neuron C Programmer’s Guide 191
Application
Scheduler
Network
MAC
Hardware
Sender Device (writer)
Application
Scheduler
Network
MAC
Hardware
Receiver Device (reader)
= data
Figure 18. Application and Network Buffers
This section outlines a few guidelines for allocating buffers, depending on the
needs of an individual application.
Buffer Size
If you use application messaging, you must set the appropriate buffer sizes to
accommodate the largest message that the application or Neuron firmware could
generate or receive for processing. In some cases, this could require an increase
in buffer size. If you only use network variables, the compiler chooses buffer
sizes based on the size of the largest network variable that you declare and the
minimum sizes required by the Neuron firmware.
Figure 19 shows the basic components of an application buffer and a network
buffer. An application buffer contains application message data and system
overhead. A network buffer contains application message data, protocol layer 2
through layer 5 overhead, and system overhead.
Application
Message
Application
Message Protocol L2 - L5
System Overhead
Network Buffer
Application Buffer
System Overhead
Figure 19. System and Protocol Overhead in Application and Network
Buffers
Application Buffer Size
The size of an application buffer is equal to the following:
message_size + 5 bytes of system overhead