NEO-M8P - Hardware Integration Manual
UBX-15028081 - R05
Early Production Information
Hardware description
Page 8 of 27
1.5
I/O pins
1.5.1
RESET_N: Reset input
Driving
RESET_N
low activates a hardware reset of the system. Use this pin only to reset the module. Do not use
RESET_N
to turn the module on and off, since the reset state increases power consumption. With NEO-M8P
module
RESET_N
is an input only.
1.5.2
EXTINT: External interrupt input
EXTINT
is an external interrupt pin with fixed input voltage thresholds with respect to
VCC
(see the
NEO-M8P
Data Sheet
[1] for more information). It can be used for functions such as accurate external frequency aiding and
ON/OFF control. Leave open if unused, this function is disabled by default.
1.5.3
SAFEBOOT_N: input
If the
SAFEBOOT_N
pin is “low” at power up, the NEO-M8P module starts in Safe Boot Mode and doesn’t begin
GNSS operation. The Safe Boot Mode can be used to recover from situations where the Flash has become
corrupted.
1.5.4
D_SEL: input
The
D_SEL
pin selects the available interfaces between SPI and UART/DDC operation.
If open, the UART and DDC ports are active. If pulled low, the SPI interface is available. See the
NEO-M8P Data
Sheet
1.5.5
LNA_EN: Antenna ON (LNA enable), output
In Power Save Mode, the system can turn on/off an optional external LNA using the LNA_EN signal in order to
optimize power consumption.
1.5.6
TIMEPULSE: output
A configurable time pulse signal is available with NEO-M8P modules. The time pulse signal is configured as one
pulse per second by default. For more information on programming this function, see the
u-blox 8 / u-blox M8
Receiver Description including Protocol Specification
1.5.7
RTK_STAT: output
The
RTK_STAT
pin provides an indication of the RTK positioning status. At start up this pin is set high. When
receiving a valid stream of RTCM 3 messages the pin alternates between high and low at the navigation rate, e.g.
the default rate is 1Hz. It is set into a continuous low output when the receiver is operating in RTK fixed mode.
1.5.8
GEOFENCE_STAT: output
This pin indicates the current geofence status, if activated. The pin active polarity and geofence locations are preset
using the UBX-NAV-GEOFENCE message allowing up to four circular areas to be defined. Once activated, the
receiver continuously compares its current position with the preset geofenced areas. The pin state reflects the
current Geofence status as to whether the receiver is inside any of the active areas. See the
u-blox 8 / u-blox M8
Receiver Description including Protocol Specification
[2] for more information.
1.5.9
Electromagnetic interference on I/O lines
Any I/O signal line with a length greater than a ~3 mm can act as an antenna and may pick up arbitrary RF signals
transferring them as noise into the GNSS receiver. This specifically applies to unshielded lines, in which the
corresponding GND layer is remote or missing entirely, or lines close to the edges of the printed circuit board.
If, for example, a cellular signal radiates into an unshielded I/O line, it is possible to generate noise of the order of
many volts which not only distort receiver operation but can also damage it permanently.
