NimbeLink Skywire NL-SWNDK User manual

Skywire® Nano Development Kit
User Manual
NimbeLink Corp
Updated: July 2020

PN 1002398 rev 1 © NimbeLink Corp. 2020. All rights reserved. 1

Table of Contents

Table of Contents 2
Introduction 3
Scope 3
Orderable Devices 3
Product Overview 3
Important Note on the included SIM cards 4
Connect to the Development Kit 5
Unpack the Kit 5
Connecting the Modem to the Development Kit 6
Communicating with the Skywire Nano 11
Install a Terminal Emulator Program 11
Default Serial Port Settings 11
Modem Enumeration on the Host PC 11
Test Serial Communication 13
Disable Cellular Functionality 14
Set the Desired SIM Interface 14
Activate Modem (One-Time Step) 15
Configure the PDP Context 16
Enable Cellular Functionality 17
Verify the Network Registration Status 17
Test Signal Strength 19
Common Next Steps 21
Appendix 22
APN Configuration 22
Overview 22
Common APN's and Their Respective Carriers 22
 
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1. Introduction
1.1 Scope
This document serves as the user manual for the Skywire Nano Development Kit.
1.2 Orderable Devices
Orderable Device
Description
Carrier
NL-SWNDK
Skywire Nano Development Kit
Any
NL-SWN-LTE-NRF9160
Skywire Nano, Global, CAT M1, NBIoT, GPS
Any

1.3 Product Overview
The NL-SWNDK is a development kit made for use specifically with the Skywire Nano             
embedded cellular modem that enables easy development and integration of the          
Skywire® Nano into a custom design.
The NL-SWNDK offers the following critical features and functionality:
●One micro-USB connector, J2, that provides 5V, 500mA power to the board, and            
enables easy communication between the host PC and the modem.
●Two SMA to U.FL connectors for cellular and GPS antennas
●Two 20-pin headers for connection to modem's GPIO pins, and other signals.
●3FF SIM slot that adds support for various other SIM cards and cellular carriers.
For more information regarding the development kit, please refer to the NL-SWNDK           
datasheet and design files:
Datasheet: Coming Soon
Design Files:
https://nimbelink.com/Documentation/Development_Kits/NL-SWNDK/1002333_REVB_
NL-SWNDK_Design_Files.zip
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1.4 Important Note on the included SIM cards
The NL-SWNDK development kit includes two SIM card       
identities, a physical AT&T 3FF SIM card, and Verizon MFF2         
SIM chip which is soldered on the modem assembly.
The NL-SWN-LTE-NRF9160 modem is certified for use on       
Verizon network and carriers that honor PTCRB certifications. 
If you wish to use the Verizon cellular network, the soldered          
SIM chip can be activated. If you wish to use a different           
carrier network, a physical SIM card can be inserted into the          
3FF SIM card connector slot on the development kit baseboard.
At this time, the AT&T SIM card provided in the kit should not be used. The Nordic                
Semiconductor nRF9160 cellular module SiP (System in Package) has not completed          
AT&T's network certification. When the SiP and modem complete the AT&T          
certification, this document will be updated to include additional instructions for how           
to use the provided AT&T SIM card.
All questions can be sent to: [email protected] 
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2. Connect to the Development Kit
2.1 Unpack the Kit
The Skywire® Nano Development Kit includes an NL-SWN-LTE-NRF9160 Skywire Nano         
modem with soldered-down Verizon LTE-M SIM, mounting screws and tool, NL-SWNDK          
Development Kit baseboard, micro-USB cable, cellular antenna, and an AT&T SIM card.
The picture below shows the contents of the development kit when unboxed:

 
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2.2 Connecting the Modem to the Development Kit
For convenience, the NL-SWNDK ships pre-assembled with the modem already mated          
to the baseboard, and with the U.FL antenna connectors attached to the modem.
However, the instructions below explain how to install the modem into the baseboard:
1. Gather the following material that come with the kit:
a. Skywire Nano Development Kit PCB
b. Skywire Nano Cellular Modem
c. Mounting Screw(s)
d. Hex Key Tool
It is also strongly recommended to use a U.FL removal tool in order to prevent damage               
to the modem's U.FL connectors when unmating the connectors. The following part is a             
suitable tool for this purpose:
Hirose P/N: U.FL-LP(V)-N-2
2. Before connecting, ensure that the Skywire Nano is properly oriented with respect           
to the baseboard. See the image below for reference:


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3. Install the Skywire Nano onto the Skywire Nano interface.
a. Ensure that the modem is properly lined up with the 60-pin connector and            
the steel spacer on the baseboard before applying any force.
b. Once the modem is oriented properly, press down gently on the top of the             
modem, perpendicular to the surface of the modem.

4. Using the provided hex key tool, insert a mounting screw into the screw hole on              
the modem and baseboard. Gently tighten the screw until it meets resistance.

 
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5. Attach the female U.FL connectors on the baseboard to the male U.FL           
connectors on the modem.
a. Connector J12 on the baseboard should be mated with the LTE antenna           
connector, X1, on the modem.
b. Connector J13 on the baseboard should be mated with the GPS antenna           
connector, X3, on the modem.

 
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6. Attach the provided LTE Antenna to connector J12 on the development kit.
a. The antenna should be positioned such that it is sticking straight up,           
perpendicular to the development kit in order to ensure the best possible           
signal quality.

 
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7. If desired, attach a compatible GPS antenna to connector J13 on the           
development kit.
Do not attach a passive antenna (such as a cellular
antenna) to the modem's GPS connector X3. Doing so
may cause irreparable damage to the modem's GPS
interface.
The Skywire Nano datasheet has a list of recommended
active GPS antennas that are compatible with the modem.
See Section 4.13.4 at the link below for more details:
https://nimbelink.com/Documentation/Skywire/Nano/4G_LTE_Cat_M1_Nordic/1
002347_NL-SWN-LTE-NRF9160_Datasheet.pdf
8. Attach the provided USB cable to connector J2 on the development kit, and the             
other end to the host PC. This will cause the modem to power on and enumerate               
on the host PC.

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3. Communicating with the Skywire Nano
3.1 Install a Terminal Emulator Program
In order to communicate with the modem, a terminal emulator program such as Tera             
Term, PuTTY, or an equivalent must be used.
If the user does not have a preferred terminal emulator program, please refer to the              
following recommendations:
Windows Users:
●Download Tera Term at the following link:
○https://ttssh2.osdn.jp/index.html.en
Linux Users:
●Download PuTTY with the following terminal command:
○[sudo] apt install putty
3.2 Default Serial Port Settings
The Skywire Nano requires the following default serial port settings:
Parameter
Value
Default Baud Rate
115200 bps
Data Bits
8
Parity Bit
N
Stop Bit(s)
1
When setting up the connection to the modem in the chosen terminal emulator program,
make sure that everything is configured to match the default settings.
3.3 Modem Enumeration on the Host PC
When the NL-SWNDK is connected via the USB cable, it will enumerate differently            
depending on the OS of the host PC. Instructions for Linux and Windows users are              
found on the next two pages. 
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Windows Users:
The NL-SWNDK will enumerate on a Windows host PC as three COM ports. These COM              
ports will be named something like "JLink CDC UART Port".
The image below depicts the enumeration for the NL-SWNDK on a Windows 10 PC, as              
seen in the Tera Term "New Connection" menu:

The Segger J-Link drivers for the development kit should automatically install when the            
development kit is plugged into the test PC.
If this is not the case, please refer to the following link. Download and install the J-Link                
Software and Documentation Pack:
https://www.segger.com/downloads/jlink/#J-LinkSoftwareAndDocumentationPack
The COM port that is connected to the modem's AT command parser serial port             
(UART1) may vary from PC to PC. Using Tera Term, test out each COM port until the AT                 
interface is found. 
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Linux Users:
The NL-SWNDK will enumerate on a Linux PC as three ACM devices. The AT parser for               
the modem should be connected to /dev/ttyACM1, but this may vary from system to             
system.
The serial port settings in PuTTY may need to be adjusted before connecting the             
modem. These can be accessed in Tera Term by going to Setup -> Serial Port. The               
settings can be updated in Putty by navigating to Connection -> Serial.
The serial settings should be as follows:
Baud Rate: 115200 bps
Data: 8bit
Parity: none
Stop: 1bit
Flow Control: none



3.4 Test Serial Communication
In the terminal program, type the command:
AT
followed by the Enter key, and the terminal should respond with:
OK 
Note: The modem will output "ERROR" when a command is entered incorrectly. To
enable verbose error mode to see what error is occuring issue AT+CMEE=2 to the
modem. 
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
3.5 Disable Cellular Functionality
As soon as power is applied to the NL-SWNDK, the Skywire          
Nano will boot up, and attempt to connect to the cellular          
network using the on-board soldered-down SIM by default.
Since the soldered-down SIM is not currently activated, the        
modem should be unable to connect to the network. This will          
trigger the automatic backoff sequence on the modem, which        
delays the next network connection for a certain amount of time          
as per GSMA standards.
After the backoff timer expires, the modem will attempt to connect to the network once              
more. If the connection fails again, the timer is reset for a longer period of time, and the                 
process continues.
To prevent subsequent failed connections while the modem's soldered-down SIM is          
inactive, the modem's cellular functionality should be disabled temporarily. Type the          
following command:
AT+CFUN=4
followed by the Enter key, and the modem should respond with:
OK
3.6 Set the Desired SIM Interface
By default, the modem uses the soldered-down SIM card. However, users can swap            
between the soldered-down SIM card, and the external SIM interface on the NL-SWNDK            
using the AT#SIMSELECT command.
Note: The #SIMELECT setting is saved by the modem, and will persist across reboots.
To use the external SIM card connector with a compatible SIM card of your choice, type               
the command:
AT#SIMSELECT=1
followed by the Enter key, and the terminal should respond with:
OK
To use the onboard solder-down SIM chip, type the command:
AT#SIMSELECT=0
followed by the Enter key, and the terminal should respond with:
OK
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To query which SIM interface is being used, issue the command:
AT#SIMSELECT?
followed by the Enter key, and the terminal should respond with:
#SIMSELECT: x
OK
where xis either 0or 1. 0means the onboard soldered-down SIM is selected, and 1                
means the external SIM connector is selected.
3.7 Activate Modem (One-Time Step)
If you are using a new Skywire Nano cellular modem, it does
not have an active cellular plan.
To activate the modem's soldered-down Verizon SIM, visit
https://go.nimbelink.com, create an account, and activate the
SIM with a cellular data plan.
Alternatively, a SIM from a cellular carrier that honors PTCRB
certifications can also be used.
The AT&T SIM card that is included with the development kit must not be used, as per
the guidance in Section 1.4.
To activate a new plan for the modem's soldered-down SIM, the International Mobile
Equipment Identity (IMEI) of the modem and the Integrated Circuit Card Identifier
(ICCID) of the SIM must be recorded.
First, select the soldered-down SIM interface as outlined in Section 3.6. Query the ICCID
of this SIM with the following command:
AT#ICCID?
followed by the Enter key, and the modem will reply with:
#ICCID: <ICCID>
OK
where <ICCID> is the ICCID of the soldered-down SIM.
 
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Next, query the IMEI of the modem with the following command:
AT+CGSN
followed by the Enter key, and the modem will reply with:
<IMEI>
OK
where <IMEI> is the IMEI of the modem.
Use these two values to activate the Skywire Nano on https://go.nimbelink.com or
directly with your desired cellular carrier partner.
3.8 Configure the PDP Context
Before the modem can successfully register on the cellular network, a Packet Data            
Protocol (PDP) context may need to be configured on the modem.
The PDP context is used to set up the connection between the modem and the network,               
including specifying the Access Point Name (APN) that the modem should use for the             
connection.
Verizon Users:
Mobile equipment using Verizon's LTE network will have their APN's automatically          
pushed to them during the network registration process. Therefore, setting up a PDP            
context is not usually required.
Verizon users should skip the setting of the PDP context, and attempt to connect             
without setting one. If for some reason the modem cannot connect with the automatic             
APN push, refer to the AT+CGDCONT command below for PDP context configuration.
Non-Verizon Users:
Networks other than Verizon typically require that a PDP context be configured before            
attempting to register on the network.
In the terminal program, type the command:
AT+CGDCONT=0,“IPV4V6”,”APN”
where APN is the individual APN for the chosen network. To find the network’s APN              
please see Section 4.2.
Press the Enter key, and the terminal program should respond with:
OK
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To verify that the APN was set correctly, in the terminal program type the command:
AT+CGDCONT?
followed by the Enter key, and the terminal should respond with:
+CGDCONT: 0,”IPV4V6”,”APN”
OK
Section 5.1 contains further information regarding APN's, and some common APN's         
that users may encounter.
3.9 Enable Cellular Functionality
After the chosen SIM card has been activated, and the PDP context is configured (if
applicable) the modem is ready to connect to the network.
To instruct the modem to enable its cellular radio and attempt to connect to the network,
send the following command:
AT+CFUN=1
followed by the Enter key, and the modem should respond with:
OK
3.10 Verify the Network Registration Status
To test whether the modem has registered on the network, the AT+CEREG command
can be used. To query the current registration status, send the following command:
AT+CEREG?
followed by the Enter key, and the modem should respond with:
+CEREG: 0,<n>
OK
Where <n> is replaced with the current network registration status.
If the modem is registered on the network, the response to the AT+CEREG? command             
should be:
+CEREG: 0,1
OK
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If the modem is still searching for the network, the response to the AT+CEREG?             
command should be:
+CEREG: 0,2
OK
If the modem's registration was denied, the response to the AT+CEREG? command           
should be:
+CEREG: 0,3
OK
A "registration denied" status is a good indication that the PDP context was set             
incorrectly, or that the SIM is not active. Verify that the APN was set correctly (if               
applicable), and that the SIM is indeed activated with your cellular carrier.
If the modem's registration status is unknown or indeterminable, the response to the            
AT+CEREG? command should be:
+CEREG: 0,4
OK
This status is a good indication that the signal quality conditions are too low, and the               
modem is unable to connect.
Verify that the J12 antenna connector is properly seated in the modem's X1 connector,             
and ensure that the testing area has acceptable signal quality. Moving closer to a             
window, or outdoors can help to improve LTE signal quality.
Section 3.11 also has information on the signal quality AT command that can help to             
identify low signal quality problems.
If the modem is registered and roaming, the response to the AT+CEREG? command            
should be:
+CEREG: 0,5
OK
Please refer to the Skywire Nano AT Command Manual for more information regarding            
the AT+CEREG command and all others:
https://nimbelink.com/Documentation/Skywire/Nano/4G_LTE_Cat_M1_Nordic/100239
9_NL-SWN-LTE-NRF9160_AT-Command-Manual.pdf
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3.11 Test Signal Strength
To check the signal strength on any LTE modem the user should refer to the RSRP               
(Reference Signal Received Power) & RSRQ (Reference Signal Received Quality) values          
reported by the modem.
These signal measurements will accurately reflect the quality of the cellular link for LTE             
modems. Typical values are as follows:
Values of <rsrq>
RSRQ (Reference Signal Received Quality)
0
RSRQ < -19.5 dB
1
-19.5 dB ≤ RSRQ < -19 dB
2
-19 dB ≤ RSRQ < -18.5 dB
...
...
32
-4 dB ≤ RSRQ < -3.5 dB
33
-3.5 dB ≤ RSRQ < -3 dB
34
-3 dB ≤ RSRQ
255
Not known or detectable

Values of <rsrp>
RSRP (Reference Signal Received Power)
0
RSRP < -140 dBm
1
-140 dBm ≤ RSRP < -139 dBm
2
-139 dBm ≤ RSRP < -138 dBm
...

95
-46 dBm ≤ RSRP < -45 dBm
96
-45 dBm ≤ RSRP < -44
97
-44 dBm ≤ RSRP
255
Not known or not detectable

 
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The table below contains estimated signal qualities base on the values in the previous
tables:

<rsrq>
RSRQ
<rsrp>
RSRP
Quality
0
RSRQ < -19.5 dB
0 - 40
RSRP < -100 dBm
Marginal
1 - 9
-19.5 dB ≤ RSRQ < -15 dB
41 - 50
-100 dBm ≤ RSRP < -90 dBm
Fair
10 - 19
-15 dB ≤ RSRQ < -10 dB
51 - 59
-90 dBm ≤ RSRP < -80 dBm
Good
20 - 34
≥ -10 dB
60 - 97
≥ -80 dBm
Excellent

To query the current signal strength seen by the modem, type this command:
AT+CESQ
followed by the Enter key, and the terminal should respond with:
+CESQ: <rxlev>,<ber>,<rscp>,<ecno>,<rsrq>,<rsrp>
Where <rsrq>,<rsrp> are the RSRP/RSRQ values as defined by the modems AT           
command manual.
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