u-blox NEO-8Q, NEO-M8 User Manual
Abstract
This document describes the features and specifications of u-blox NEO-8Q and NEO-M8 series
modules.
www.u-blox.com
UBX-15029985 - R07
NEO-8Q / NEO-M8
u-blox 8 / M8 GNSS modules
Hardware integration manual
NEO-8Q / NEO-M8 - Hardware integration manual
Title
NEO-8Q / NEO-M8
Subtitle
u-blox 8 / M8 GNSS modules
Document type
Hardware integration manual
Document number
UBX-15029985
Revision and date
R07
26-May-2020
Document status
Production Information
Product status
Corresponding content status
In Development /
Prototype
Objective Specification
Target values. Revised and supplementary data will be published later.
Engineering Sample
Advance Information
Data based on early testing. Revised and supplementary data will be published later.
Initial Production
Early Production Information
Data from product verification. Revised and supplementary data may be published later.
Mass Production /
End of Life
Production Information
Document contains the final product specification.
European Union regulatory compliance
NEO-8Q and NEO-M8N/M/Q/T modules comply with all relevant requirements for RED 2014/53/EU. The NEO-8Q and NEOM8N/M/Q/T Declaration of Conformity (DoC) is available at www.u-blox.com in Support > Product resources > Conformity
Declaration.
Product name
Type number
ROM/FLASH version
PCN reference
NEO-M8N
NEO-M8N-0-11
FLASH FW SPG 3.01
UBX-20013367
NEO-M8M
NEO-M8M-0-10
ROM SPG 3.01
UBX-16013121
NEO-M8Q
NEO-M8Q-0-11
ROM SPG 3.01
UBX-20013367
NEO-M8T
NEO-M8T-0-11
FLASH FW3.01 TIM 1.10
UBX-20013367
NEO-8Q
NEO-8Q-0-11
ROM SPG 3.01
UBX-20013367
u-blox or third parties may hold intellectual property rights in the products, names, logos and designs included in this
document. Copying, reproduction, modification or disclosure to third parties of this document or any part thereof is only
permitted with the express written permission of u-blox.
The information contained herein is provided “as is” and u-blox assumes no liability for its use. No warranty, either express or
implied, is given, including but not limited to, with respect to the accuracy, correctness, reliability and fitness for a particular
purpose of the information. This document may be revised by u-blox at any time without notice. For the most recent
documents, visit www.u-blox.com.
Copyright © u-blox AG.
Document information
This document applies to the following products:
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Contents
Document information ................................................................................................................................ 2
Contents .......................................................................................................................................................... 3
1 Hardware description ........................................................................................................................... 5
1.1 Overview ........................................................................................................................................................ 5
1.2 Configuration ............................................................................................................................................... 5
1.3 Connecting power ....................................................................................................................................... 5
1.3.1 VCC: Main supply voltage ................................................................................................................. 5
1.3.2 V_BCKP: Backup supply voltage ...................................................................................................... 5
1.3.3 VDD_USB: USB interface power supply ......................................................................................... 6
1.3.4 VCC_RF: Output voltage RF ............................................................................................................. 6
1.4 Interfaces ...................................................................................................................................................... 6
1.4.1 UART ..................................................................................................................................................... 6
1.4.2 USB ........................................................................................................................................................ 7
1.4.3 Display Data Channel (DDC) ............................................................................................................. 7
1.4.4 SPI .......................................................................................................................................................... 8
1.4.5 TX_READY ............................................................................................................................................ 8
1.5 I/O pins ........................................................................................................................................................... 8
1.5.1 RESET_N: Reset .................................................................................................................................. 8
1.5.2 EXTINT: External interrupt ............................................................................................................... 8
1.5.3 SAFEBOOT_N ...................................................................................................................................... 9
1.5.4 D_SEL: Interface select ..................................................................................................................... 9
1.5.5 TIMEPULSE (TIMEPULSE1 on NEO-M8T) .................................................................................... 9
1.5.6 TIMEPULSE2 ....................................................................................................................................... 9
1.5.7 LNA_EN: LNA enable .......................................................................................................................... 9
1.6 Electromagnetic interference on I/O lines ...........................................................................................10
2 Design ..................................................................................................................................................... 11
2.1 Pin description ...........................................................................................................................................11
2.1.1 Pin name changes.............................................................................................................................12
2.2 Minimal design...........................................................................................................................................12
2.3 Layout: Footprint and paste mask ........................................................................................................12
2.4 Antenna .......................................................................................................................................................13
2.4.1 Antenna design with passive antenna .........................................................................................13
2.4.2 Active antenna design .....................................................................................................................15
2.5 Layout design-in: Thermal management .............................................................................................16
3 Migration to u-blox 8 / M8 modules .............................................................................................. 17
3.1 Migrating u-blox 7 designs to NEO-8Q and NEO-M8 series modules ............................................17
3.2 Hardware migration of NEO-6 to NEO-8Q and NEO-M8 series .......................................................17
3.3 Software migration ...................................................................................................................................18
4 Product handling ................................................................................................................................. 19
4.1 Packaging, shipping, storage and moisture preconditioning ..........................................................19
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4.2 Soldering .....................................................................................................................................................19
4.3 EOS/ESD/EMI precautions ......................................................................................................................22
4.4 Applications with cellular modules ........................................................................................................25
Appendix ....................................................................................................................................................... 27
A Glossary ................................................................................................................................................. 27
B Recommended parts ......................................................................................................................... 27
Related documents ................................................................................................................................... 29
Revision history .......................................................................................................................................... 30
Contact .......................................................................................................................................................... 31
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1 Hardware description
1.1 Overview
u-blox NEO-8Q, NEO-M8N, NEO-M8Q, and NEO-M8M standard precision GNSS modules, and the
NEO-M8T timing GNSS module, all feature the high performance u-blox M8 GNSS engine. Available
in the industry standard NEO form factor in a leadless chip carrier (LCC) package, they are easy to
integrate and combine exceptional positioning performance with highly flexible power, design, and
connectivity options. SMT pads allow fully automated assembly with standard pick & place and
reflow-soldering equipment for cost-efficient, high-volume production enabling short time-tomarket.
☞ For product features, see the corresponding product data sheet in the Related documents section.
☞ To determine which u-blox product best meets your needs, see the product selector tables on the
u-blox website www.u-blox.com.
1.2 Configuration
The configuration settings can be modified using UBX protocol configuration messages, see the ublox 8 / u-blox M8 Receiver Description including Protocol Specification [4]. The modified settings
remain effective until power-down or reset. If these settings have been stored in BBR (Battery Backed
RAM), then the modified configuration will be retained, as long as the backup battery supply is not
interrupted.
For the NEO-M8N module, configuration can be saved permanently in SQI flash.
1.3 Connecting power
The u-blox NEO-8Q and NEO-M8 series modules have three power supply pins: VCC, V_BCKP, and
VDD_USB.
1.3.1 VCC: Main supply voltage
The VCC pin provides the main supply voltage. During operation, the current drawn by the module can
vary by some orders of magnitude, especially if enabling low-power operation modes. For this reason,
it is important that the supply circuitry be able to support the peak power for a short time (for the
specifications, see the corresponding product data sheet in the Related documents section).
☞ When switching from backup mode to normal operation or at start-up, u-blox NEO-8Q and NEO-
M8 series modules must charge the internal capacitors in the core domain. In certain situations,
this can result in a significant current draw. For low power applications using Power Save and
backup modes, it is important that the power supply or low ESR capacitors at the module input
can deliver this current/charge.
☞ Use a proper GND concept. Do not use any resistors or coils in the power line.
1.3.2 V_BCKP: Backup supply voltage
If the module supply has a power failure, the V_BCKP pin supplies the real-time clock (RTC) and
battery backed RAM (BBR). Use of valid time and the GNSS orbit data at start up will improve the
GNSS performance, as with hot starts, warm starts, AssistNow Autonomous and AssistNow Offline.
If no backup battery is connected, the module performs a cold start at power up.
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Figure 1: Backup battery and voltage (for exact pin orientation, see the corresponding product data sheet)
☞ Avoid high resistance on the V_BCKP line: During the switch from main supply to backup supply,
a short current adjustment peak can cause high voltage drop on the pin with possible
malfunctions.
☞ If no backup supply voltage is available, connect the V_BCKP pin to VCC.
☞ As long as power is supplied to the NEO-8Q and NEO-M8 series modules through the VCC pin, the
backup battery is disconnected from the RTC and the BBR to avoid unnecessary battery drain (see
Figure 1). In this case, VCC supplies power to the RTC and BBR.
Real-Time Clock (RTC)
The RTC is driven by a 32 kHz oscillator using an RTC crystal. If the main supply voltage fails, and a
battery is connected to V_BCKP, parts of the receiver switch off, but the RTC still runs providing a
timing reference for the receiver. This operating mode is called Hardware Backup Mode, which enables
all relevant data to be saved in the backup RAM to allow a hot or warm start later
1.3.3 VDD_USB: USB interface power supply
VDD_USB supplies the USB interface. If the USB interface is not used, the VDD_USB pin must be
connected to GND. For more information about correctly handling the VDD_USB pin, see section 1.4.
1.3.4 VCC_RF: Output voltage RF
The VCC_RF pin can supply an active antenna or external LNA. For more information, see section 2.4.
1.4 Interfaces
1.4.1 UART
The NEO-8Q and NEO-M8 series modules include a Universal Asynchronous Receiver Transmitter
(UART) serial interface RXD/TXD supporting configurable baud rates. The baud rates supported are
specified in the corresponding product data sheet.
The signal output and input levels are 0 V to VCC. An interface based on RS232 standard levels (+/12 V) can be implemented using level shifters such as Maxim MAX3232. Hardware handshake signals
and synchronous operation are not supported.
☞ Designs must allow access to the UART pin for future service and reconfiguration.
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Module
VDD_USB
LDO
VDD_USB
R4
USB_DP
USB_DM
R5
C24 C23
D2
VBUS
DP
DM
GND
USB
Device Connector
U1
EN R11
EN
Name
Component
Function
Comments
U1
LDO
Regulates VBUS (4.4 …5.25 V)
down to a voltage of 3.3 V.
Almost no current requirement (~1 mA) if the GNSS receiver is
operated as a USB self-powered device.
C23, C24
Capacitors
Required according to the specification of LDO U1
D2
Protection
diodes
Protect circuit from overvoltage /
ESD when connecting.
Use low capacitance ESD protection such as ST Microelectronics
USBLC6-2.
R4, R5
Serial
termination
resistors
Establish a full-speed driver
impedance of 28…44
A value of 27 is recommended.
R11
Resistor
100 k is recommended for USB self-powered setup.
1.4.2 USB
A USB version 2.0 FS (Full Speed, 12 Mbit/s) compatible interface is available for communication as
an alternative to the UART. The USB_DP integrates a pull-up resistor to signal a full-speed device to
the host. The VDD_USB pin supplies the USB interface.
u-blox provides Microsoft® certified USB drivers for Windows Vista, Windows 7, Windows 8 and
Windows 10 operating systems. These drivers are available at our website at www.u-blox.com
USB external components
The USB interface requires some external components to implement the physical characteristics
required by the USB 2.0 specification. These external components are shown in Figure 2 and listed in
Table 1. To comply with USB specifications, VBUS must be connected through an LDO (U1) to pin
VDD_USB on the module.
In USB self-powered mode, the power supply (VCC) can be turned off and the digital block is not
powered. In this case, since VBUS is still available, the USB host would still receive the signal indicating
that the device is present and ready to communicate. This should be avoided by disabling the LDO
(U1) using the enable signal (EN) of the VCC-LDO or the output of a voltage supervisor. Depending on
the characteristics of the LDO (U1) it is recommended to add a pull-down resistor (R11) at its output
to ensure VDD_USB is not floating if the LDO (U1) is disabled or the USB cable is not connected, that
is, VBUS is not supplied.
☞ USB bus-powered mode is not supported.
Figure 2: USB interface
Table 1: Summary of USB external components
1.4.3 Display Data Channel (DDC)
An I2C compatible Display Data Channel (DDC) interface is available on NEO-8Q and NEO-M8 series
modules for serial communication with an external host CPU. The interface only supports operation
in slave mode (master mode is not supported). The DDC protocol and electrical interface are fully
compatible with the Fast-Mode of the I2C industry standard. DDC pins SDA and SCL have internal
pull-up resistors.
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For more information about the DDC implementation, see the u-blox 8 / u-blox M8 Receiver
Description Including Protocol Specification [4]. For bandwidth information, see the corresponding
product data sheet. For timing parameters, consult the I2C-bus specification [7].
☞ The NEO-8Q and NEO-M8 series DDC interface supports serial communication with most u-blox
cellular modules. See the specification of the applicable cellular module to confirm compatibility.
1.4.4 SPI
An SPI interface is available for communication to a host CPU.
☞ SPI is not available in the default configuration, because its pins are shared with the UART and
DDC interfaces. The SPI interface can be enabled by connecting D_SEL to ground. For speed and
clock frequency, see the corresponding product data sheet.
1.4.5 TX_READY
The TX_READY function is used to indicate when the receiver has data to transmit. A listener can wait
on the TX_READY signal instead of polling the DDC or SPI interfaces. The UBX-CFG-PRT message lets
you configure the polarity and the number of bytes in the buffer before the TX READY signal goes
active. The TX_READY function can be mapped to TXD (PIO 06). The TX_READY function is disabled
by default.
☞ The TX_READY functionality can be enabled and configured by AT commands sent to the u-blox
cellular module supporting the feature. For more information, see the GPS Implementation and
Aiding Features in u-blox wireless modules [8].
1.5 I/O pins
All I/O pins make use of internal pull-ups. Thus, there is no need to connect unused pins to VCC_IO.
1.5.1 RESET_N: Reset
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-8Q and NEO-M8 series modules RESET_N is an input only.
☞ The RTC time is also reset (but not BBR).
1.5.2 EXTINT: External interrupt
EXTINT (EXTINT0 on NEO-M8T), PIO 13 is an external interrupt pin with fixed input voltage
thresholds with respect to VCC (see the corresponding product data sheet for more information). It
can be used for wake-up functions in power save mode on NEO-8Q and NEO-M8 series modules and
for aiding. Leave open if unused. The function is disabled by default.
If the EXTINT is not used for an external interrupt function, it can be used for some other purpose. For
example, as an output pin for the TX_READY feature to indicate that the receiver has data to
transmit.
EXTINT1 is an external interrupt pin on NEO-M8T with fixed input voltage thresholds with respect to
VCC (see the corresponding product data sheet for more information). It can be used for wake-up
functions in Power Save Mode on NEO-M8T module and for aiding. Leave open if unused. The function
is disabled by default.
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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-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
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1.6 Electromagnetic interference on I/O lines
Any I/O signal line with a length greater than approximately 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, and lines close
to the edges of the printed circuit board.
If, for example, a cellular signal radiates into an unshielded high-impedance line, it is possible to
generate noise in the order of volts and not only distort receiver operation but also damage it
permanently.
On the other hand, noise generated at the I/O pins will emit from unshielded I/O lines. Receiver
performance may be degraded when this noise is coupled into the GNSS antenna (see Figure 15).
To avoid interference by improperly shielded lines, it is recommended to use resistors (e.g. R>20 ),
ferrite beads (e.g. BLM15HD102SN1) or inductors (e.g. LQG15HS47NJ02) on the I/O lines in series.
These components should be chosen with care because they will affect also the signal rise times.
Figure 3 shows an example of EMI protection measures on the RXD/TXD line using a ferrite bead. For
more information, see section 4.3.
Figure 3: EMI precautions
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