Echelon Neuron C - Manual (Page 136)

124 How Devices Communicate Using Application Messages
Type of Message Message Code Description
Responder Offline 63
(0x3F)
Used by application message
responses. Indicates that the
sender of the response was in an
offline state and could not process
the request.
Foreign Frames 64 to 78
(0x40..0x4E) Used by application-level gateways
to other networks. The
interpretation of the message code
is left to the application.
Foreign Responder
Offline
79
(0x4F)
Used by foreign frame responses.
Indicates that the sender of the
response was in an offline state
and could not process the request.
Network Diagnostic
Messages
80 to 95
(0x50..0x5F)
Used by network tools for network
diagnostics.
Network Management
Messages
96 to 127
(0x60..0x7F)
Used by network tools for network
installation and maintenance.
Network Variables 128 to 255
(0x80..0xFF) The lower six bits of the message
code contain the upper six bits of
the (14-bit) network variable
selector. The first data byte
contains the lower eight bits of the
selector.
Example of building an application message:
msg_tag motor;
#define MOTOR_ON 0
#define ON_FULL 100
msg_out.tag = motor;
msg_out.code = MOTOR_ON;
msg_out.data[0] = ON_FULL;
Block Transfers of Data
You can use the C memcpy( ) function to transfer blocks of message data into the
msg_out or resp_out objects (see Using the Request/Response Mechanism on page
136). You can also use memcpy( ) to copy a block of data from the msg_in or
resp_in objects. Using this function is the only case where you can use the
address of the msg_out, resp_out, msg_in, or resp_in objects.
For messages of an unknown or variable length, use msg_in.len or resp_in.len,
limited by the sizeof( s ) to prevent writing past the end of s .