Globalstar STX3 - Serial Packet Format; Serial Packet Commands; Send Data Command (0 x00)

8545-0198-01 Revision 1.9 STX3 Users Manual
9/24/2020 Globalstar, Inc. Confidential and Proprietary Page | 16
5.2.1 Serial Packet Format
Preamble
Fixed pattern 0xAA
Length
Total number of bytes in the serial packet including the preamble
Command
Command type (See Table 5 Serial Packet Type). Responses to
commands carry the same command type as the command that
initiated the answer
Data
Data associated with the command or answer
CRC
16 bit CRC
Figure 12 Serial Packet Format
5.2.2 Serial Packet Commands
For all serial packet commands as described below:
• AA is the Preamble.
• NN is the Length.
• XX is an unspecified byte value
• CLSB is the least significant CRC byte
• CMSB is the most significant CRC byte
• If an improperly formatted command is received, the STX3 will return a NAK response:
AA 05 FF A1 CB
5.2.2.1 Send Data (0x00)
The Send Data command requests the STX3 to send from 1 to 144 data bytes over the Globalstar Simplex network.
0x00
header
len
cmd
payload
1
payload
2
payload
3
..
payload
N
CRC1
CRC2
AA
NN
00
XX
XX
XX
XX
XX
CLSB
CMSB
Example Command: AA 0E 00 01 02 03 04 05 06 07 08 09 BE E8
Response: AA 05 00 D9 C4
The example above commands the STX3 to send 9 bytes of user defined data over the Globalstar Simplex network. If the STX3
receives a properly formatted Send Data command, it returns an acknowledge response as shown above. If the command is not
properly formatted, it will return the NAK response AA 05 FF A1 CB.