Globalstar SmartOne - Manual (Page 66)

SmartOne Manual Rev 1.4 DOC# 9100-0268-01 p.66
Message Priorities
It is possible that message types may collide. Whenever feasible, the
SMARTONE will examine its known schedule and reschedule lower priority
messages to occur after higher priority ones. If there is not enough time in
the known schedule for all scheduled messages to be transmitted in a
reasonable time, or there is insufficient memory to queue them, the lowest
priority message(s) could be dropped. In any case, unscheduled messages (for
example, Input Status Changed) shall cancel pending messages of lower
priority and not cancel pending messages of higher priority. The following
list shows the priority of message types, with the highest priority being
listed first.
• Contact Service Provider
• User Defined Raw message. *
• User Defined Truncated message. *
• Change of Location Area
• Replace Battery
• Undesired Input State
• Re-Center
• Diagnostics
• Accumulate/Count
• Input Status Changed
• Device Turned On
• Normal Location (In-Motion or At-Rest).
* The two user defined message types actually have equal priority. Either one
will cancel the other one. If, for example, the user interface commands the
device to send a Truncated message, and then, before it has time to obtain a
fix and send the message, the user commands a Raw message, the raw will be
sent.
Serial Commands
The SMARTONE uses the I/O port for unit configuration as well as interface to remote passive
and smart sensors. Two commands are provided in the unit interface to support smart sensors.
External sensors that can format and communicate to the SMARTONE can send user data
through the SMARTONE by using these two commands.
This section describes the serial interface between the SMARTONE and a
computer or other programming device. SMARTONE will respond to any
command that contains fields with invalid values with a NAK response
(command field set to 0xFF).
Serial Packet Format (commands and answers)
Communication to the SMARTONE will follow the following specific format:
Preamble
1 byte Length
1 byte Cmd
1 byte Data
Variable length 0 – 54 bytes CRC
2 byte