Product Manual

The $SL WAKE,<cause> message is emitted after the Tile wakes from a user commanded 
sleep mode (as opposed to the Tile waking to perform internal housekeeping and then returning
to sleep). The value of cause will be one of the following:
Cause
Description
GPIO
GPIO input changed from inactive to active state
SERIAL
Activity was detected on the RX pin of the Tile's UART
TIME
The S or U parameter time has been reached
If UART activity wakes the Tile, the TIMEOUT message will not be emitted as the Tile is now
awake.
In sleep mode, the real-time clock is not GPS disciplined, and is therefore subject to some
degree of drift. The longer the Tile is asleep, the more the drift will accumulate. The user should
be aware of this when selecting a sleep with a long duration.
If the GPIO1 pin is configured as an input to wake the Tile, the sleep mode will be terminated if
activity occurs on GPIO1.
If the GPIO1 pin is configured as an output that indicates the Tile's sleep mode, GPIO1 will
transition to the appropriate state if the $SL OK message is emitted.
Example:
Commanding the Tile to sleep for 1 minute:
$SL S=60*57
$SL OK*3b
$SL WAKE,TIME @ 2019-04-11 18:58:03*77
If the Tile receives any serial input before the planned wake time, then the Tile will wake with a
message such as:
$SL WAKE,SERIAL @ 2019-04-11 18:57:45*6f
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