The last feature accessible through this port is the "Easy IP config" that is used
in the "Quick start" chapter of this document.
Registers access feature
TCP/IP works in big endian: most significant byte first, followed by least
significant byte.
The access to the data is done through an easy (6 byte header) protocol
over TCP.
Structure of each packet:
1.
Function ID (2 bytes),
2.
Transaction ID (2 bytes)
3.
Length of the parameters (2 bytes)
4.
Parameters (X byte)
5.
Checksum (2 bytes) (described later in this chapter)
The user (sender) defines the values of the Transaction IDs himself. The
module that receives a command sends back an answer (for every
command). The answer contains the same Transaction ID as the
corresponding command sent. The user is also able to check execution of
each command.
Warning
:
The maximum length of parameters is 172
on this board! Pay
attention to not exceed this value in question AND answer frame. This
implies that the maximum registers that can be read at one time are almost
30 (depending on registers size). If the number of registers is too big, the
FMod-TCP DB will answer only with the value of some of them.
It is also
mandatory that the command has to be transmitted within one TCP
packet.
Otherwise, the FMod-TCP DB will ignore it.
Read register(s) command:
Byte#
Number of bits
Example
0x00
Read (0x0021)
16 bits
0x0021
0x02
TransactionID
16 bits
0x1B34
0x04
Number of registers to
read (X)
16 bits
0x0001
0x06
X * Registers Addresses
X * 8 bits
0x02
0x06+X Checksum
16 bits
0x…
