SL871 Family Product User Guide
1VV0301170 Rev. 9
Page 48 of 89
2021-07-15
Not Subject to NDA
9.3.3.2.
FORCE-ON (SL871 and SL871L only).
For typical
operation
, connect this pin through
a 10 K
Ω
resistor to ground to create a
pulldown (which will prevent noise from accidentally activating this pin).
Upon command, the module will enter the backup (low power) state.
To exit this
state
, drive the Force-on signal high (true) to force the module to return to the
full power state.
Force-on should be held high until the PMTK101 message is received (about 1 second),
then be returned to logic low.
If Force-on is high when a low-power command is received, the module will enter the
Standby (stop) state rather than the Backup state, since the PMU is still on.
This signal is only available on the SL871 (Gen 2) and SL871L.
Warning: Note that this pin has a maximum input voltage of 3.4 V
(which is lower than the max for Vcc or Vbatt).
The logic levels are shown in Table 25: Input Logic Levels: Force-On.
Output Signals
9.3.4.1.
1PPS
1PPS is a one pulse per output second signal. Its default characteristics are:
•
Pulse duration: 100 ms
•
Active: during 3D navigation.
The pulse availability and duration can be configured via the $PMTK285 command.
Options for availability are:
•
Disable
•
After 1st fix
•
3D Fix only
•
2D/3D Fix only
•
Always.
NMEA output (timestamp) can be configured to have a fixed latency behind the 1PPS
pulse of 460 to 485 ms via the $PMTK255 command. Default is variable latency.
Содержание SL871
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