sparkfun NEO-M8P-2 Hook-Up Manual page 6

These pins are used for various extra control of the NEO-M8P:
FENCE: Geofence output pin. Configured with U-Center. Will go high or low when a geofence is setup.
Useful for triggering alarms and actions when the module exits a programmed perimeter.
RTK: RTK output pin. Remains high when module is normal GPS mode. Begins blinking when RTCM
corrections are received and module enters RTK float mode. Goes low when module enters RTK fixed
mode and begins outputting cm-level accurate locations.
PPS: Pulse-per-second output pin. Begins blinking at 1Hz when module gets basic GPS/GNSS position
lock.
RST: Reset input pin. Pull this line low to reset the module.
SAFE: Safeboot input pin. This is required for firmware updates to the module and generally should not be
used or connected.
INT: Interrupt input/output pin. Can be configured using U-Center to bring the module out of deep sleep or to
output an interrupt for various module states.
Antenna
The NEO-M8P requires a good quality GPS or GNSS (preferred) antenna. A U.FL connector is provided. Note:
U.FL connectors are rated for only a few mating cycles (about 30) so we recommend you set it and forget it. A
U.FL to SMA cable threaded through the mounting hole provides a robust connection that is also easy to
disconnect at the SMA connection if needed. Low-cost magnetic GPS/GNSS antennas can be used (checkout the
ublox white paper) but a 4" / 10cm metal disc is required to be placed under the antenna as a ground plane.