Globalstar SmartOne - Manual (Page 68)

SmartOne Manual Rev 1.4 DOC# 9100-0268-01 p.68
Serial Packet Types
Cmd Description / Usage / Comment Command Data
Bytes Acknowledge Data Bytes
0x01
User requests the SMARTONE to
reply with integral ESN (Electronic
Serial Number). This is the ID used
by Globalstar to identify the unit.
None
Four data bytes, which contain the
unit ID as an unsigned integer.
The MSByte is sent first. Only the
27 LSbits are non-zero.
0x26 Send Truncated message.
See Truncated
Message section
below
None
0x27 Send Raw Message
See Raw Message
Section below
None
Send Truncated Message (serial message type 0x26)
The SMARTONE will perform a GPS location and append user data passed to the
unit via the Truncated Message command 0x26.
Two bytes plus 6 bits of user data may be sent with the standard GPS location
information in a messaging burst. Two bits are set in the on-air message by
the SmartOne informing the recipient that the message is the Truncated type.
The following table defines the message structure of the “data” portion of
the command used to send a Truncated message.
Truncated Serial Message
Byte Bit Parameter Description Default
Value
0 7:2 Submask Bits User data bits. Bits 1:0 are reserved and will be
masked by SmartOne. 0x00
Variable. User Data Any user data
Firmware version 2.0 supports a maximum of 2 total
bytes of data in this field. Version 2.1 and higher
supports a maximum of 47 total bytes in this field.
User application (smart sensor) should transmit only
as many bytes as needed (don’t “pad” the message) in
order to keep on air packets to a minimum.
Example of sending a “Truncated” user message
The host sends:
AA 08 26 10 22 33 <CRC-low> <CRC-High>
The SmartOne would respond:
AA 05 26 <CRC-Low> <CRC-High>
What would go out over the air is:
11 Lat-3 Lat-2 Lat-1 Lon-3 Lon-2 Lon-1 22 33