Cellular and Positioning Shield - User’s Guide
Copyright 2014 © Embedded Artists AB
EA2-USG-0702 v1.0 Rev A
Cellular and Positioning Shield
User’s Guide
Get Up-and-Running Quickly and
Start Developing Your Application On Day 1!
Cellular and Positioning Shield - User’s Guide
Page 2
Copyright 2014 © Embedded Artists AB
Embedded Artists AB
Davidshallsgatan 16
211 45 Malmö
Sweden
info@EmbeddedArtists.com
http://www.EmbeddedArtists.com
Copyright 2014 © Embedded Artists AB. All rights reserved.
No part of this publication may be reproduced, transmitted, transcribed, stored in a retrieval system, or
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Embedded Artists AB.
Disclaimer
Embedded Artists AB makes no representation or warranties with respect to the contents hereof and
specifically disclaim any implied warranties or merchantability or fitness for any particular purpose.
Information in this publication is subject to change without notice and does not represent a
commitment on the part of Embedded Artists AB.
Feedback
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comments to support@EmbeddedArtists.com.
Trademarks
All brand and product names mentioned herein are trademarks, services marks, registered
trademarks, or registered service marks of their respective owners and should be treated as such.
Cellular and Positioning Shield - User’s Guide
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Copyright 2014 © Embedded Artists AB
Table of Contents
1 Document Revision History 4
2 Declaration of Conformity 5
3 Introduction 6
3.1 Features 6
3.2 ESD Precaution 6
3.3 General Handling Care 7
3.4 Other Products from Embedded Artists 7
3.4.1 Design and Production Services 7
3.4.2 OEM / LPCXpresso / QuickStart Boards and Kits 7
4 Getting Started 8
4.1 Preparations 8
4.2 m-center Application 9
4.2.1 Direct USB connection on 3G version 12
4.3 UART Pass-Through Applications 12
5 Cellular and Positioning Shield Design 13
5.1 Cellular Modem 13
5.2 GNSS/GPS Receiver 14
5.3 Power Supply 14
5.4 Level Shifters 14
5.5 ArduinoTM Shield Connector 14
5.6 Raspberry Pi Connector 16
5.7 USB Connector 16
5.8 LED 16
5.9 Locating Components 16
6 Things to Note 18
6.1 SIM Card not Found 18
7 Further Information 19
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1 Document Revision History
Revision
Description
PA1
First version.
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Copyright 2014 © Embedded Artists AB
2 Declaration of Conformity
We, Embedded Artists AB, Davidshallsgatan 16, 21145 Malmö, Sweden, declare under our sole
responsibility that our products:
Cellular and Positioning Shield - GSM/GPRS (2.5G), model: EAA00202
Cellular and Positioning Shield - UMTS (3G), model: EAA00215
to which this declaration relates, conforms to the following Product Specifications:
Health and Safety Standards: EN 60950-1:2006+A11:2009+A1:2010+A12:2011+AC:2011
(R&TTE article 3.1a) EN 62311:2008
EMC Standards: EN 301 489-24 V1.5.1
(R&TTE article 3.1b) EN 301 489-7 V1.3.1
EN 301 489-1 V1.9.2
EN 61000-6-3:2007
Radio Spectrum Efficiency Standard: EN 301 511 V9.0.2
(R&TTE article. 3.2) EN 301 908-2 V6.2.1
EN 301 908-1 V6.2.1
RoHS: EN 50581:2012
Concerning article 3.3 of the R&TTE directive, no additional requirements have been considered as
relevant for this class of apparatus.
Supplementary Information:
The products herewith complies with the requirements of the Low Voltage Directive 2006/95/EC, the
EMC Directive 2004/108/EC, the R&TTE Directive 1999/5/EC, the RoHS Directive 2011/65/EU and
carries the CE-marking accordingly.
Anders Rosvall, Technical Director of Embedded Artists AB
Malmö, November 4, 2014
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Copyright 2014 © Embedded Artists AB
3 Introduction
Thank you for buying Embedded Artists’ Cellular and Positioning Shield. The shield/board has been
designed for IoT applications. It builds around high-quality cellular and positioning modules from u-
blox and has been designed in cooperation with them.
There are two versions of the shield; one 2.5G (GSM/GPRS) and 3G (UMTS) version. This document
is a User’s Guide that describes the hardware design for both versions. The document use the
LPC4088 Experiment Bundle as example platform to describe how the shields operate. The shields
have a general design and can operate together with many different platforms.
3.1 Features
Embedded Artists Cellular and Positioning Shield lets you get up-and-running quickly with IoT
applications. The features of the shield/board are:
SARA-G350-0xS GSM/GPRS module on 2.5G shield version, or
Quad-band version for global connectivity
SARA-U270-0xS UMTS module on 3G shield version
Note: UMTS/HSPA frequency bands are 900/2100 MHz and GSM/EDGE frequency
bands are 900/1800 MHz, which are commonly used in Europe/Africa/Asia, but not in
North America.
MAX-7Q-0 GPS/GNSS module on 2.5G shield version, or
MAX-M8Q-0 GPS/GNSS module on 3G shield version
SMA connectors for both modules (right-angled female)
SIM card connector (note: SIM card not included)
ArduinoTM shield and Raspberry Pi (RPi) compatible connectors for external interface
UART interface to cellular module
I2C interface to positioning module
POWER_ON and GPS_EXTINT GPIO signals
Note that RPi pin header is not soldered - just pads on pcb
On-board power supply
Requires external 5-12V DC / 1Amp power supply
Input power via micro-B USB connector, Arduino shield connectors or RPi expansion
connector
Dimensions
Compact size: 54 x 66 mm (including SMA connectors)
Note that antenna connectors will build to the 66mm measure.
3.2 ESD Precaution
Please note that the Cellular and Positioning Shield come without a case/box
and all components are exposed for finger touches and therefore extra
attention must be paid to ESD (electrostatic discharge) precaution.
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Copyright 2014 © Embedded Artists AB
Make it a habit always to first touch the metal surface of one of the SMA connectors for a few
seconds with both hands before touching any other parts of the boards. That way, you will have
the same potential as the board and therefore minimize the risk for ESD.
In general touch as little as possible on the boards in order to minimize the risk of ESD damage.
Note that Embedded Artists does not replace boards that have been damaged by ESD.
3.3 General Handling Care
Handle the Cellular and Positioning Shield with care. The board is not mounted in a protective
case/box and is not designed for rough physical handling. Connectors can wear out after excessive
use. The Cellular and Positioning Shield is designed for prototyping use, and not for integration into an
end-product.
Note that Embedded Artists does not replace boards what have been improperly handled.
3.4 Other Products from Embedded Artists
Embedded Artists have a broad range of LPC based boards that are very low cost and developed for
prototyping / development as well as for OEM applications (i.e., for integration). Modifications for OEM
applications can be done easily, even for modest production volumes. Contact Embedded Artists for
further information about design and production services.
3.4.1 Design and Production Services
Embedded Artists provide design services for custom designs, either completely new or modification to
existing boards. Specific peripherals and I/O can be added easily to different designs, for example,
communication interfaces, specific analog or digital I/O, and power supplies. Embedded Artists has a
broad, and long, experience in designing industrial electronics in general and with NXP’s LPC
microcontroller families in specific. Our competence also includes wireless and wired communication
for embedded systems.
3.4.2 OEM / LPCXpresso / QuickStart Boards and Kits
Visit Embedded Artists’ home page, www.EmbeddedArtists.com, for information about other products
or contact your local distributor.
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Copyright 2014 © Embedded Artists AB
4 Getting Started
This chapter contains information about how to get acquainted with the Cellular and Positioning Shield.
Please read this section first before you start using the board - it will be well spent time!
4.1 Preparations
This section walks through the preparations that must be done to get the system (i.e., Cellular and
Positioning shield) up and running.
First, acquire a standard size SIM card (sometimes also called "mini SIM") and mount it in the SIM
card holder. Make sure the it supports data communication. The picture below illustrates how to mount
the SIM card.
Figure 1 Mounting SIM Card
Step 1) Push metal lock in red arrow direction
Step 2) Lift up the SIM card older
Step 3) Insert SIM card (contacts down, polarizing
corner as shown in picture)
Step 4) Push back the SIM card holder and push
metal lock in green arrow direction to secure the
SIM card in correct position.
Mounted SIM card
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Copyright 2014 © Embedded Artists AB
Next, connect the shield to a system. It can be via the Arduino, Raspberry Pi connectors or, in the case
of the 3G version, a direct USB connection to a PC. As an illustrated example, the picture below shows
the shield mounted on the LPC4088 Experiment Bundle.
Figure 2 Shield Mounted on LPC4088 Experiment Bundle
The next step is to mount the antennas. Only use the antennas that are shipped with the shield. The
picture above also shows where the GPS/GNSS and cellular antennas shall be mounted. The
GPS/GNSS antenna has a big puck/box at the very end and a long antenna cable. The cellular
antenna is short and connects directly to the SMA connector.
The final step is to provide an external power source to the shield. A 5-12V DC / 1Amp supply is
suitable. Three options exist:
Power the shield via the micro-B USB connector. This will by default be a 5V supply, for
example a USB charger.
Power the shield via the Arduino connectors; either the +5V power supply or the VIN (12V
max) power supply can power the shield, whichever has highest voltage.
Power the shield via the Raspberry Pi connector; pin 2, 4 are +5V input and pin 6, 9, 14, 20,
25 are ground.
4.2 m-center Application
u-box has created a (Windows) PC application for direct evaluation, configuration and testing of the
cellular modem. The application is called m-center. The PC application communicates with the
cellular modem via the UART channel. The application can be downloaded from here: http://www.u-
GPS/GNSS antenna
connector
Cellular and
Positioning shield
Cellular antenna
connector
micro-B USB
connector for
powering
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Copyright 2014 © Embedded Artists AB
blox.com/en/evaluation-tools-a-software/u-center/m-center.html and there is also an associated user's
manual for the application. This section will just describe how to get the initial connection. The rest of
the details can be found in the m-center manual.
Embedded Artists has created a 'UART pass-through' application on the LPC4088 QuickStart Board. It
can be downloaded from the LPC4088 Experiment Base Board project page:
https://developer.mbed.org/users/embeddedartists/notebook/lpc4088-experiment-base-board---
projects/
When the m-center application has started the main window looks like below. Start with selecting the
virtual COM port to connect to. In this case, the virtual OCM port that the HDK on the LPC4088
QuickStart board creates.
Figure 3 m-center Main Window
Select the HDK COM port and set 115200 bps, 8N1, no flow control.
Figure 4 m-center Set COM Port
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Next, press the Connect-button and then the Initialization-button. The cellular modem information will
be displayed in the lower left corner.
Figure 5 m-center Main Window, Modem Connected
In the upper right corner it is possible to click on AT Terminal-button to open a terminal window where
direct AT commands can be sent. Consult the cellular modem AT command manual for details.
Figure 6 m-center, AT Terminal
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4.2.1 Direct USB connection on 3G version
The 3G version of the cellular modem has direct USB support, so connecting the a PC to the micro-B
USB connector on the shield will give a direct access (via virtual COM ports) to the cellular modem. No
'UART pass-through' application is needed (and no base board either).
4.3 UART Pass-Through Applications
Embedded Artists has created a 'UART pass-through' application on the LPC4088 QuickStart Board. It
can be downloaded from the LPC4088 Experiment Base Board project page:
https://developer.mbed.org/users/embeddedartists/notebook/lpc4088-experiment-base-board---
projects/
The application can be used to allow the m-center PC application to communication with the cellular
modem via the mbed HDK virtual COM port.
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5 Cellular and Positioning Shield Design
This chapter contains information about the hardware design of the Cellular and Positioning Shield and
the different options on the board. The schematic can be downloaded in pdf format from the product
page, and is recommended to have printed out while reading this chapter.
The picture below gives an overview of the Cellular and Positioning Shield design.
Figure 7 Cellular and Positioning Shield Overview
5.1 Cellular Modem
The cellular modem from u-blox is one of two versions (SARA-G350 or SARA-U270, depending on
shield version). The modules are pin compatible. A SIM card connector with ESD protection and
antenna connector (SMA) are connected to the modem.
The cellular module is accessed via the UART interface per default design of the shield. Only RXD and
TXD are connected but by mounting configuration resistors R62/R63 RTS and CTS signals can be
added to the interface.
Signal MDM_PWR_ON controls the PWR_ON signal on the cellular modem.
Normally the UART channel of the modem is used to communicate with it. The SARA-U270 modem
also has a USB channel, as an alternative communication channel.
Arduino shield
connectors
SIM card connector
Cellular modem
module
Raspberry Pi
connector pads
micro-B USB
connector
Cellular antenna
connector
GPS/GNSS antenna
connector
GPS/GNSS
positioning module
Status LEDs
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5.2 GNSS/GPS Receiver
The position module from u-blox is one of two versions (MAX-7Q or MAX-M8Q, depending on shield
version). The modules are pin compatible. An antenna connector (SMA) is connected to the module. A
0.22F super capacitor can power the positioning module for some time to keep time.
The position module is accessed via the I2C interface per default design of the shield. There is
configuration resistors that are not mounted that allows for UART access (by mounting R68/R69) or
letting the cellular modem communicate with the module (mount R78/R79). U-blox cellular modems
has a positioning tunneling mode for simpler access of both a cellular and positioning module via just
one serial interface.
The positioning module directly controls one LED for the once-a-second pulse. The signal can be
made accessible via a configuration resistor (mount R66).
5.3 Power Supply
The power supply on the board is straight forward and simple, yet flexible. An external supply (5-14V
DC / 1Amp min) is converted to 3.8V for the cellular modem. A switched DC/DC converter is used,
switching at 2.5 MHz. The external power supply comes from:
+5V on Arduino or Raspberry Pi connectors, or
VIN pin on Arduino connector, or
micro-B USB connector
An LDO created a 3.3V (from the 3.8V supply) to power the positioning module.
5.4 Level Shifters
The level shifters translate between the 3.3V I/O voltage of the shield and the cellular modem I/O
voltage (1.8V).
5.5 ArduinoTM Shield Connector
There are four male/female connectors around the board edge that together form an Arduino UNO R3
compatible shield connector.
Arduino Signals
RPi Signals
Usage
Note
SCL
Pin 5,
SCL/GPIO1
I2C communication with
positioning module
Input to shield.
SDA
Pin 3,
SDA/GPIO0
I2C communication with
positioning module
Bidirectional signal.
D13: GPIO/SPI-SCK
Not connected
Not connected
D12: GPIO/SPI-MISO
Not connected
Not connected
D11: GPIO/PWM/SPI-MOSI
Not connected
Not connected
D10: GPIO/PWM/SPI-SSEL
Not connected
Not connected
D9: GPIO/PWM
Not connected
Normally not connected
Connected to positioning
module RXD if
configuration resistor
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R69 is mounted.
Input to shield.
D8: GPIO
Not connected
Normally not connected
Connected to positioning
module TXD if
configuration resistor
R68 is mounted.
Output from shield.
D7: GPIO
Pin 13,
GPIO21
Connected to positioning
module, signal:
GPS_EXTINT
Input to shield.
D6: GPIO/PWM
Pin 15,
GPIO22,
normally not
connected
Normally not connected
Connected to positioning
module, signal:
GPS_PPS (one-a-
second pulse signal).
Output from shield.
D5: GPIO/PWM
Not connected
Not connected
D4: GPIO
Pin 16,
GPIO23
Connected to cellular
module PWR_ON
D3: GPIO/PWM
Pin 12,
GPIO18,
normally not
connected
Normally not connected
Connected to cellular
module CTS if
configuration resistor
R63 is mounted.
Output from shield.
D2: GPIO
Pin 11,
GPIO17,
normally not
connected
Normally not connected
Connected to cellular
module RTS if
configuration resistor
R62 is mounted.
Input to shield.
D1: GPIO/UART-TXD
Pin 8,
TXD/GPIO14
Connected to cellular
module RXD
Input to shield.
D0: GPIO/UART-RXD
Pin 10,
RXD/GPIO15
Connected to cellular
module TXD
Output from shield.
A5: GPIO/AIN/I2C-SCL
Not used
Not used
A4: GPIO/AIN/I2C-SDA
Not used
Not used
A3: GPIO/AIN
Not connected
Not connected
A2: GPIO/AIN
Not connected
Not connected
A1: GPIO/AIN
Not connected
Not connected
A0: GPIO/AIN
Not connected
Not connected
IOREF
Not connected
Not connected
RESET
Pin 7, normally
not connected
Normally not connected
Can control reset of the
positioning module if
configuration resistor
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Copyright 2014 © Embedded Artists AB
R91 is mounted.
Can control reset of the
cellular module if
configuration resistor
R90 is mounted.
VIN
Does not exist
Can power the shield if
highest voltage is present
on this net.
Note: 5-14V DC, 1Amp
5V
Can power the shield if
highest voltage is present
on this net.
3.3V
Not connected
Not connected
5.6 Raspberry Pi Connector
The Raspberry Pi (RPi) connector pads are compatible with the 2x13 pos expansion connector found
on the RPi. The shield and RPi can easily be connected with the help of a 26-pos flat cable. Note that
pin headers must be soldered.
The RPi connections are placed in parallel over the Arduino connectors and are numbered according
to the Arduino pins. See table under Arduino pinning for details.
An external power supply is needed in most cases since the RPi cannot deliver enough current for the
cellular modem.
5.7 USB Connector
This is a micro-AB connector. When SARA-G350 is mounted this connector can only be used for
powering the shield. When SARA-U270 is mounted it is an optional USB interface that can connect to
a PC or an embedded system with a USB Host interface (and appropriate software driver). In the latter
case, the USB connector can also be used to just power the shield.
5.8 LED
There are three LEDs:
Yellow - signals presence of 3.3V, i.e. the shield is powered.
Green - the once per second pulse from the GPS/GNSS module.
Red - is a configurable indicator connected to GPIO1 on the cellular module.
5.9 Locating Components
There are nine configuration resistors on the board. The picture below shows their location. Normally
there is no need to change the default setting but for prototyping situations, some of them can be
mounted.
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Figure 8 Configuration Resistor Locations
R90
R91
R62
R63
R69
R68
R66
R79
R78
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6 Things to Note
This chapter contains information that can be relevant to check in case some problems or issues
appear when using the shield.
6.1 SIM Card not Found
If the cellular modem gives a message that the SIM cards cannot be found it is likely that a power
cycle is needed - not just removing and inserting the SIM card again. Remember that all supply
voltages to the shield must be removed during the power cycle.
In the system integration manuals for the cellular modems it is clearly stated in section 2.5 that the
modules do not support SIM hot insertion / removal.
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7 Further Information
The LPC4088 microcontroller is a complex circuit and there exist a number of other documents with a
lot more information. The following documents are recommended as a complement to this document.
[1] u-blox SARA-U270 UMTS/HSPA/GSM modem information
http://www.u-blox.com/en/wireless-modules/umtshsdpa-modules/sara-u2-series.html
[2] u-blox SARA-G350 GSM/GPRS modem information
http://www.u-blox.com/en/wireless-modules/gsm-gprs-modules/sara-gsm-module-family.html
[3] u-blox MAX-7M GPS/GNSS module
http://www.u-blox.com/en/gps-modules/pvt-modules/max-7.html
[4] u-blox MAX-M8 GPS/GNSS module
http://www.u-blox.com/en/gps-modules/pvt-modules/max-m8-series-concurrent-gnss-
modules.html
[5] LPCware, NXP's community for developers
http://www.lpcware.com/
[6] LPCXpresso IDE: NXP's low-cost development platform for LPC families, which is an Eclipse-
based IDE.
http://www.lpcware.com/lpcxpresso
[7] LPCOpen - a Software Development Platform for NXP's LPC Microcontrollers
http://www.lpcware.com/lpcopen
[8] mbed.org, the official site for mbed development and gives access to all documentation and
the on-line compiler.
http://mbed.org
Note that there can be newer versions of the documents/links than the ones listed above. Always
check for the latest information/version.
Mouser Electronics
Authorized Distributor
Click to View Pricing, Inventory, Delivery & Lifecycle Information:
Embedded Artists:
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