Note that ALL time representations now use the T date and time delimiter as indicated in ISO
8901
EXCEPT FOR THE $DT COMMAND.
Ex. 2022-01-26T08:30:00.
Messages
All messages sent to or from the Hive have an
Application ID
tag associated with them. The
Application ID
can be an arbitrary number from 0 to 64999, and may be used by the user to
organize messages (ex:
Application ID
1000 could be used for device telemetry, 2000 for
commands to the device and 3000 for emergencies). Swarm reserves
Application ID
values
65000 to 65535 for internal use. Specifying an
Application ID
in the reserved range will result
in unexpected operation and the messages may be lost.
See the
command section in the command directory below for an example
implementation of the Application ID.
Implementation of NMEA checksum in C
uint8_t nmeaChecksum (const char *sz, size_t len)
{
size_t i = 0;
uint8_t cs;
if (sz [0] == '$')
i++;
for (cs = 0; (i < len) && sz [i]; i++)
cs ^= ((uint8_t) sz [i]);
return cs;
}
© 2022 SWARM TECHNOLOGIES
SWARM M138 MODEM PRODUCT MANUAL · REV 1.20 · FEBRUARY 2022
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36
