SIM2 C3X LINK
3. Communication Protocol
The communication protocol is packet oriented. Packets consists of Header and Payload.
There are two types of packets: Event and Operation.
The packet header size is fixed (7 bytes), while the packet payload type and content varies based on the type of packet: Event payload size is 6 bytes, while Operation payload size is 25 bytes.
The entire packet size is variable, being the sum of the
Header
All Packets use the same Packet Header format.
The Packet Header size is fixed at seven bytes.
0
BE
1
EF
2
Packet Type
34
Packet Payload Size
56
Packet Checksum (CRC)
0xEFBE is a fixed value that is used to insure packet alignment if there are partial packets received or byte lost. The
The Packet Type is a number (a byte in length) that defines the type of data in the packet.
The Packet Payload Size is a number (two bytes) that defines the size of the payload portion of the packet. For a given Packet Type, Packet Size is fixed.
The Packet Checksum (two bytes) is the CRC value for the entire packet (Header and Payload).
Payload
The packet payload format depends on the packet type.
The Event packet payload size is 6 bytes, while the Operation packet payload size is 25 bytes.
Event Packet Format:
01
Event
2
00
3
00
4
00
5
00
Operation Packet Format:
0
Op Type
1 2
Op ID
3
00
4
00
5 6
Op Target
7
00
8
00
9 10 11
Op Value | 00 |
|
|
12
00
13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 |
|
|
|
|
|
|
|
|
|
|
|
|
00
00
00
00
00
00
00
00
00
00
00
00
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