Ublox NEO-M8N - Safeboot_N; D_SEL: Interface Select; TIMEPULSE (TIMEPULSE1 on NEO-M8 T); Timepulse2

NEO-8Q / NEO-M8 - Hardware integration manual
UBX-15029985 - Production information Hardware description Page 9 of 10
C1-Public
Power control
The power control feature allows overriding the automatic active/inactive cycle of power save mode.
The state of the receiver can be controlled through the EXTINT (EXTINT0 on NEO-M8T) pin. The
receiver can also be forced OFF using EXTINT (EXTINT0 on NEO-M8T) when power save mode is not
active.
Frequency aiding
The EXTINT (EXTINT0 on NEO-M8T) pin can be used to supply time or frequency aiding data to the
receiver.
For time aiding, hardware time synchronization can be achieved by connecting an accurate time pulse
to the EXTINT (EXTINT0 on NEO-M8T) pin.
Frequency aiding can be implemented by connecting a periodic rectangular signal with a frequency up
to 500 kHz and arbitrary duty cycle (low/high phase duration must not be shorter than 50 ns) to the
EXTINT (EXTINT0 on NEO-M8T) pin. Provide the applied frequency value to the receiver using UBX
messages.
1.5.3 SAFEBOOT_N
The SAFEBOOT_N pin is for future service, updates and reconfiguration.
On the NEO-M8T module, a configurable TIMEPULSE2 signal can be programmed on
TP2/SAFEBOOT_N.
☞ Do not pull low during reset.
1.5.4 D_SEL: Interface select
The D_SEL pin selects the available interfaces. SPI cannot be used simultaneously with UART/DDC. If
open, UART and DDC are available. If pulled low, the SPI interface is available. See the corresponding
product data sheet.
1.5.5 TIMEPULSE (TIMEPULSE1 on NEO-M8T)
On NEO-8Q and NEO-M8 series modules, a configurable time pulse signal is available. By default, the
time pulse signal is configured to one pulse per second. For more information, see the u-blox 8 / u-blox
M8 Receiver Description including Protocol Specification [4].
1.5.6 TIMEPULSE2
On the NEO-M8T module, a configurable TIMEPULSE2 signal can be programmed on
TP2/SAFEBOOT_N.
For more information, see the u-blox 8 / u-blox M8 Receiver Description including Protocol
Specification [4].
☞ The TIMEPULSE2 output must not be held LOW during start-up.
1.5.7 LNA_EN: LNA enable
On NEO-M8N, NEO-M8J, NEO-M8Q, NEO-M8T and NEO-8Q modules, 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.
Signals: "high" = Turn ON LNA, "low" = Turn OFF LNA