Ublox NINA-B222-04B Quick setup guide

UBX-18011096 - R05
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NINA-B2 series
Stand-alone dual-mode Bluetooth modules
System integration manual
Abstract
This document describes the system integration of NINA-B2 series stand-
alone Bluetooth®
modules. The NINA-B2 modules come with pre-flashed application software and support dual-mode
Bluetooth (Bluetooth BR/EDR and Bluetooth low energy). The
module has many important security
features embedded, including secure boot, which ensures that only authenticated software can run
on the module. This makes NINA-B2 ideal for critical IoT applications where security is important.


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Document information
Title NINA-B2 series
Subtitle Stand-alone dual-mode Bluetooth modules
Document type System integration manual
Document number UBX-18011096
Revision and date R05 1-Nov-2021
Disclosure Restriction C1- Public
Product status Corresponding content status
Functional Sample Draft For functional testing. Revised and supplementary data will be published later.
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.
This document applies to the following products:
Product name Product status
NINA-B221 Initial Production
NINA-B222 Initial Production
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 info
rmation. 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.

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Contents
Document information .............................................................................................................................2
Contents .......................................................................................................................................................3
1System description ............................................................................................................................5
1.1 Overview........................................................................................................................................................5
Block diagram......................................................................................................................................5
1.2 Product description ....................................................................................................................................6
Radio in NINA-B2 series.....................................................................................................................6
1.3 CPU.................................................................................................................................................................6
1.4 Operating modes.........................................................................................................................................6
Power modes .......................................................................................................................................6
1.5 Supply interfaces ........................................................................................................................................6
Module supply design (VCC).............................................................................................................6
Digital I/O interfaces reference voltage (VCC_IO)........................................................................7
VCC application circuits ....................................................................................................................7
1.6 System function interfaces ......................................................................................................................7
Boot strapping pins............................................................................................................................7
1.7 Serial Interfaces ..........................................................................................................................................8
Universal asynchronous serial interface (UART) .........................................................................8
Serial peripheral interface (SPI).......................................................................................................8
1.8 Antenna interfaces.....................................................................................................................................9
Antenna pin – NINA-B221 .................................................................................................................9
Integrated antenna – NINA-B222....................................................................................................9
1.9 Reserved pins (RSVD) ................................................................................................................................9
1.10GND pins .....................................................................................................................................................10
2Software ............................................................................................................................................. 11
2.1 NINA-B2 u-connectXpress software.....................................................................................................11
2.2 s-center evaluation software..................................................................................................................11
2.3 Updating NINA-B2 ....................................................................................................................................11
2.4 Updating u-connectXpress software with s-center ..........................................................................12
2.5 Updating u-connectXpress software from host/AT Commands....................................................13
Setting up the serial port ................................................................................................................14
Updating u-connectXpress connectivity software....................................................................15
3Design-in............................................................................................................................................. 17
3.1 Overview......................................................................................................................................................17
3.2 Supply interfaces ......................................................................................................................................17
Module supply (VCC) design...........................................................................................................17
Digital I/O interfaces reference voltage (VCC_IO)......................................................................17
3.3 Antenna interface.....................................................................................................................................18
RF transmission line design (NINA-B221 only) ..........................................................................18
Antenna design (NINA-B221).........................................................................................................20
On-board antenna design (NINA-B222).......................................................................................23
3.4 Data communication interfaces ............................................................................................................23

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Asynchronous serial interface (UART) design............................................................................23
3.5 General High Speed layout guidelines ..................................................................................................23
General considerations for schematic design and PCB floor-planning.................................24
Module placement ............................................................................................................................24
Layout and manufacturing.............................................................................................................24
3.6 Module footprint and paste mask .........................................................................................................24
3.7 Thermal guidelines ...................................................................................................................................25
3.8 ESD guidelines ...........................................................................................................................................25
4Handling and soldering................................................................................................................... 26
4.1 ESD handling precautions.......................................................................................................................26
4.2 Packaging, shipping, storage, and moisture preconditioning .........................................................26
4.3 Reflow soldering process.........................................................................................................................27
Cleaning ..............................................................................................................................................28
Other notes ........................................................................................................................................28
5Approvals............................................................................................................................................ 29
5.1 General requirements ..............................................................................................................................29
5.2 FCC/IC End-product regulatory compliance........................................................................................29
NINA-B2 series FCC ID and IC certification number..................................................................29
Antenna requirements ....................................................................................................................29
6Product testing................................................................................................................................. 31
6.1 u-blox in-line production testing............................................................................................................31
6.2 OEM manufacturer production test .....................................................................................................32
“Go/No go” tests for integrated devices ......................................................................................32
Appendix .................................................................................................................................................... 33
Related documents ................................................................................................................................ 34
Revision history ....................................................................................................................................... 34
Contact....................................................................................................................................................... 35

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1System description
1.1 Overview
The NINA-B2 series are small stand-alone dual-mode Bluetooth modules designed for ease-of-use
and integration in professional applications where security is important. The modules are delivered
with u-blox connectivity software, which provides support for both peripheral and central roles, Serial
Port Profile, GATT client and server, beacons, u-blox Bluetooth low energy Serial Port Service – all
configurable from a host using AT commands.
NINA-B222 comes with an internal antenna while NINA-B221 has a pin for use with an external
antenna. The internal PIFA antenna is specifically designed for the small NINA form factor and
provides an extensive range, independent of ground plane and component placement.
Block diagram
Figure 1: Block diagram of NINA-B2 series
Flash (16Mbit)
Linear voltage regulators
RF
ROM
IO buffers
2xXtensa 32-bit LX6 MCU
S
RAM (4Mbit)
Cryptographics
hardware
accelerations
Antenna
(NINA-B222)
PLL
Quad SPI
VCC_IO
VCC (3.0
- 3.6
V)
40 MHz
Reset
UART
EFUSE
GPIO
BPF
ANT (NINA-
B221)
Bluetooth
baseband

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1.2 Product description
Radio in NINA-B2 series
The NINA-B2 series modules support Bluetooth BR/EDR, and Bluetooth Low Energy as explained in
Table 1.
Bluetooth BR/EDR Bluetooth low energy
Bluetooth v4.2+EDR
Maximum number of slaves: 7
Bluetooth 4.2 Low Energy dual-mode
Band support
2.4 GHz, 79 channels
Band support
2.4 GHz, 40 channels
Typical conducted output power
- 1 Mbit/s: 6 dBm
- 2/3 Mbit/s: 8 dBm
Typical conducted output power
6 dBm
Typical conducted output power
- 1 Mbit/s: 6 dBm
- 2/3 Mbit/s: 8 dBm
Typical conducted output power
6 dBm
Typical radiated output power
- 1 Mbit: 9 dBm EIRP*
- 2/3 Mbit/s: 11 dBm EIRP*
Typical radiated output power
9 dBm EIRP*
Conducted sensitivity
-88 dBm
Conducted sensitivity
-88 dBm
Data rates:
1 / 2 / 3 Mbit/s
Data rates:
1 Mbit/s
* RF power including maximum antenna gain (3 dBi).
Table 1: NINA-B2 series - Bluetooth characteristics
1.3 CPU
The NINA-B2 series has a dual-core system with two Harvard Architecture Xtensa LX6 CPUs with
maximum 240 MHz internal clock frequency. The internal memory of NINA-B2 includes the following:
•448 Kbyte ROM for booting and core functions
•520 Kbyte SRAM for data and instruction
•16 Mbit FLASH for code storage including hardware encryption to protect programs and
data
•1 kbit EFUSE (non- erasable memory) for MAC addresses, module configuration, Flash-
Encryption, and Chip-ID
1.4 Operating modes
Power modes
The NINA-B2 series modules are power efficient devices capable of operating in different power
saving modes and configurations. Different sections of the module can be powered off when not
needed and complex wake up events can be generated from different external and internal inputs.
1.5 Supply interfaces
Module supply design (VCC)
The NINA-B2 series modules use an integrated Linear Voltage converter to transform the supply
voltage presented at the VCC pin into a stable system voltage.

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Digital I/O interfaces reference voltage (VCC_IO)
All modules in the NINA-B2 series provide an additional voltage supply input for setting the I/O voltage
level.
The separate VCC_IO pin enables integration of the module in many applications with different
voltage levels (for example, 1.8 V or 3.3 V) without any level converters. The NINA-B2 modules support
only 3.3 V as IO voltage level currently.
VCC application circuits
The power for the NINA-B2 series modules is provided through the VCC pins, which can be one of the
following:
•Switching Mode Power Supply (SMPS)
•Low Drop Out (LDO) regulator
The SMPS is the ideal choice when the available primary supply source has higher value than the
operating supply voltage of the NINA-B2 series modules. The use of SMPS provides the best power
efficiency for the overall application and minimizes current drawn from the main supply source.
⚠While selecting SMPS, ensure that AC voltage ripple at switching frequency is kept as low as
possible. Layout shall be implemented to minimize impact of high frequency ringing.
The use of an LDO linear regulator is convenient for a primary supply with a relatively low voltage
where the typical 85-90% efficiency of the switching regulator leads to minimal current saving. Linear
regulators are not recommended for high voltage step-down as they will dissipate a considerable
amount of energy.
DC/DC efficiency should be evaluated as a tradeoff between active and idle duty cycle of the specific
application. Although some DC/DC can achieve high efficiency at extremely light loads, a typical
DC/DC efficiency quickly degrades as idle current drops below a few mA greatly reducing the battery
life.
It is considered as a best practice to have decoupling capacitors on the supply rails close to the
NINA-B2 series module, although depending on the design of the power routing on the host system,
capacitance might not be needed.
See the NINA-B2 series data sheet [2]
for electrical specifications.
1.6 System function interfaces
Boot strapping pins
There are several boot configuration pins available on the module that must have the correct settings
during boot (see Table 2). The boot strap pins are configured to the default state internally on the
module and must NOT be configured externally.
During boot, pin 32 controls if additional system information should be transmitted on the UART
interface during startup. After the system has booted, it is reconfigured to SPI_CS,the SPI chip select
signal.
During boot, pin 36 controls the voltage level of the internal flash during startup. After the system
has booted, it is reconfigured to the SPI slave data output signal, SPI_MISO. It must NOT be pulled
down by an external MCU or circuitry.

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Pin State during boot Default Behavior Description
27 0 ESP boot mode (factory boot) ESP Factory boot
Mode/RMII clock line.
1 Pull-up* Normal Boot from internal Flash
32 0 Silent Printout on UART0 TXD
during boot
1 Pull-up* UART0 TXD Toggling
36 0 VDD_SDIO=3.3V (Not allowed) Internal flash voltage
1 10 kΩpull-up VDD_SDIO=1.8V
(VDD_SDIO should always be at 1.8 V)
*About 30 kΩ
Table 2: NINA-B2 series boot strapping pins
1.7 Serial Interfaces
Universal asynchronous serial interface (UART)
The NINA-B2 series module provides a Universal Asynchronous Serial Interface (UART) for data
communication. The following UART signals are available:
•Data lines (RXD as input, TXD as output)
•Hardware flow control lines (CTS as input, RTS as output)
•DSR and DTS are used to set and indicate the system modes
The UART can be used as 4-wire UART with hardware flow control and 2-wire UART with only TXD and
RXD. In 2-wire mode, CTS must be connected to the GND on the NINA-B2 module.
The UART interface is also be used for firmware upgrade. See also Software.
The u-connectXpress software adds the DSR and DTR pins to the UART interface. These pins are not
used as they were originally intended but are used instead to control the state of NINA modules.
Depending on the configuration, DSR can be used to:
•Enter command mode
•Disconnect and/or toggle connectable status
•Enable/disable the rest of the UART interface
•Enter/wake up from the Stop mode
The functionality of the DSR and DTR pins are configured by AT commands. See also the
u-connectXpress AT commands manual [1] for more information.
See NINA-B2 series data sheet [2] for characteristic information about the UART interface.
Interface Default configuration
UART interface 115200 baud, 8 data bits, no parity, 1 stop bit, hardware flow control
Table 3: Default settings for the UART port while using the u-blox connectivity software
It is advisable to make the UART available either as test points or connected to a header for firmware
upgrade.
The IO level of the UART will follow the VCC_IO.
Serial peripheral interface (SPI)
⚠On NINA-B2, SPI is supported from software version 3.0.0 onwards.
In addition to UART support, NINA-B2 modules also include a Serial Peripheral Interface (SPI) for data
communication. The module acts as an SPI slave.

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The following SPI signals are available:
•Chip select as input (SPI_CS)
•Data lines (SPI_MOSI as input, and SPI_MISO as output)
•Clock (SPI_SCLK as input)
•Optional hardware flow control lines (SPI_NORX and SPI_DRDY as output)
For details on SPI operation, see the Communicating with a u-blox module over SPI bus, application
note [7].
1.8 Antenna interfaces
The antenna interface is different for each module variant in the NINA-B2 series.
Antenna pin – NINA-B221
NINA-B221 modules are equipped with an RF pin. The RF pin has a nominal characteristic impedance
of 50 Ωand must be connected to the antenna through a 50 Ωtransmission line to allow reception of
radio frequency (RF) signals in the 2.4 GHz frequency band.
Choose an antenna with optimal radiating characteristics for the best electrical performance and
overall module functionality. An internal antenna, integrated on the application board or an external
antenna that is connected to the application board through a proper 50 Ωconnector can be used.
While using an external antenna, the PCB-to-RF-cable transition must be implemented using either a
suitable 50 Ωconnector, or an RF-signal solder pad (including GND) that is optimized for 50 Ω
characteristic impedance.
1.8.1.1 Antenna matching
The antenna return loss should be as good as possible across the entire band when the system is
operational to provide optimal performance. The enclosure, shields, other components, and
surrounding environment will impact the return loss seen at the antenna port. Matching components
are often required to retune the antenna to bring the return loss within an acceptable range.
It is difficult to predict the actual matching values for the antenna in the final form factor. Therefore,
it is a good practice to have a placeholder in the circuit that includes a ”pi” network, with two shunt
components and a series component in the middle. This provides maximum flexibility while the tuning
is matched to the antenna feed.
1.8.1.2 Approved antenna designs
NINA-B2 modules come with a pre-certified design that can be used to save costs and time during the
certification process. To take advantage of this service, you have to implement the antenna layout
according to the u-blox reference designs. The reference design is available on request from u-blox.
The designer integrating a u-blox reference design into an end-product is solely responsible for the
unintentional emission levels produced by the end product.
The module may be integrated with other antennas. In this case, the OEM installer must certify his
design with respective regulatory agencies.
Integrated antenna – NINA-B222
NINA-B222 modules are equipped with an integrated antenna on the module for simpler integration.
1.9 Reserved pins (RSVD)
RSVD pins should be left unconnected.

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1.10 GND pins
Good connection of the module GND pins, with solid ground layer of the host application board, is
required for correct RF performance. This significantly reduces the EMC issues and provides a
thermal heat sink for the module.

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2Software
2.1 NINA-B2 u-connectXpress software
NINA-B2 is delivered with the u-blox connectivity software.
Using industry-standard AT commands, this is the software that manages the combination of
Bluetooth and Bluetooth Low Energy connectivity supported in NINA-B2 standalone modules.
The u-blox connectivity software enables the use of Bluetooth, controlled by the AT commands over
the UART interface. For more information on the features and capabilities of the u-blox connectivity
software and how to use it, see also the u-connectXpress AT commands manual [1] and
u-connectXpress user guide [5]
.
Figure 2 shows the structure of the embedded u-connectXpress software delivered in NINA-B2
standalone modules.
Figure 2: NINA-B2 u-connectXpress software structure
2.2 s-center evaluation software
u-blox s-center client software provides a convenient tool with which to configure u-blox standalone
modules. It runs on PCs running Windows XP onwards (x86 and x64) with Net Framework 4.5 or later
and is available for download from www.u-blox.com. For further information about how to use this tool,
see also the s-center user guide [6].
2.3 Updating NINA-B2
To ensure that the module only boots with the original u-blox software, the secure bootloader initiates
a signature verification on the flashed software binary before it is booted.
NINA-B2 u-connectXpress software can be re-flashed over the UART interface using AT commands
or the s-center client software available from the u-blox website. The flash procedure uses the
XMODEM protocol.
The following pins should be made available as either headers or test points to flash the module:
•UART (RXD, TXD, CTS, RTS)
•Pin 27

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•RESET_N
•SWITCH_1 and SWITCH_2 (optional)
To enable re-programming of the module, UART signals connected to host must not interfere with
the flashing procedure. UART pins must be put in tri-state by host or have the possibility to
disconnect completely. Another option is to let host software handle the update procedure (e.g.,
implement the XMODEM protocol or a UART pass-through function).
2.4 Updating u-connectXpress software with s-center
The u-connectXpress software, flashed into NINA-B2 module prior to delivery, is used to validate the
hardware, bootloader, and binary image. The u-connectXpress software runs only on validated
hardware.
Updates of the u-connectXpress software is available for download from www.u-blox.com. Distributed
in a single ZIP container, the software includes one binary file and one JSON file that contains the
software label, software description, file name, version, flash address, image size, image id, file
permissions, and signature file for the Connectivity Software application:
•Java Script Object Notation:
NINA-B22X-CF-<version>.json. For example: NINA-B22X-CF-1.0.json
•Connectivity Software:
NINA-B22X-SW-x.y.z-<build>.bin. For example: NINA-B22X-SW-4.0.0-003.bin
•Signature File: NINA-B22X-SI-4.0.0-003.bin
⚠To update NINA-B2 u-connectXpress requires s-center software version 4.7 or later. See also the
s-center user guide [5].
Procedure:
1. Connect the supplied serial cable on EVK-NINA-B2 to the USB port your computer. For further
information about setting up EVK-NINA-B2, see also EVK-NINA-B2 user guide [5].
2. Download and the latest version of the s-center and u-connectXpress software from u-blox
Product Resources. See also the EVK-NINA-B2 user guide [5] and s-center user guide [5].
3. Start s-center and choose "USB Serial Port (COMx)" in the drop-down “COM Port” menu. All other
dialog settings are set to default.
4. Select Open Port. A series of AT commands and response are shown in the “Console Window”.
5. Select Tools > Software Update.

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☞Secure boot functionality is supported in u-connect v4.7 and above.
7. Select Update. The module then reboots using the secure bootloader and application starts
automatically.
2.5 Updating u-connectXpress software from host/AT
Commands
☞You can send AT commands to NINA-B2 to execute certain tasks over the serial interface, using
open-source terminal emulator software that supports XMODEM, like TeraTerm or ExtraPuTTy.
Alternatively, you can send all AT commands described in this section using the s-center
software in AT mode. The examples given in this procedure have been created and tested on
EVK-NINA-B2 using TeraTerm. See also the u-connectXpress AT command manual [5] and
Bootloader protocol specification [5].
The bootloader must be running when the software is “sent” to the module. You start the bootloader
using either:
•AT commands
•Pressing the SWITCH_1 and SWITCH_2 simultaneously during a module reset (initiated by setting
RESET_N low).
☞In contrast to the s-center configuration, UART hardware flow is not used for updating software
using AT commands. The file download uses standard XMODEM-CRC16 protocol and 128 bytes
packets.
Prerequisites
As a prerequisite to updating software using AT commands, you must open the JSON file included in
the download container and make note of the defined values to be parsed with the update command
as shown in Figure 3. You also need to copy the signature given in the related txt files, as shown in
Figure 4. This information is needed during the install. The defined values to include in the command,
together with the signature file (NINA-B22X-SI-x.x.x-xxx.txt), are shown in Table 4.

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Figure 3: Defined values for Connectivity Software as shown in the JSON file
Figure 4: Typical Connectivity Software signature file
Command syntax
You use the software update command AT+UFWUPD with following syntax to update the
u-connectXpress software.
AT+UFWUPD=<mode>,<baud_rate>[,<id>,<size>,<signature>,<name>,<flags>]
The defined values for each parameter are shown in Table 4.
Parameter Type Description
<mode>
Enumerator Download mode:
0: Update mode for the Connectivity Software through the serial port
1: Bootloader mode for update of the SoftDevice through the serial port.
<baud rate>
Enumerator Baud rate in bits per second: 115200 (default), 230400, 460800, or 921600
<id>
Integer ID number of the software image.
<size>
Integer Size of the firmware image. Enter the size integer for the respective software as
defined in the NINA-B22X-SI-x.x.x-xxx.txt file. Shown in hex format in the JSON
file but must entered as bytes in decimal notation in the command.
<signature>
String RSA signature of the firmware image as base64-encoded string.
Enter the 344-character text string defined in the
NINA-B22X-SI-x.x.x-xxx.txt
file.
<name>
String The name of the firmware. Maximum string length is 22.
<flags>
String Permissions for using the firmware image. Permission flags are marked in UNIX style:
"rwx" is the default flag for the u-connectXpress software.
"
rw
" is the default flag for other binary images.
Table 4: Defined values for update parameters
Setting up the serial port
☞You can send AT text commands to NINA-B2 to execute tasks using open-source terminal
emulator software that supports XMODEM like TeraTerm or ExtraPuTTy. Alternatively, you can
send all AT commands described in this section using the s-center software in AT mode.
[
{
"Label": "ConnectivitySoftware",
"Description": "NINA-B22X u-blox connectivity software",
"File": "NINA-B22X-SW-4.0.0-003.bin",
"Version": "NINA-B22X-SW-4.0.0-003",
"Address": "0x20000",
"Size": "0xA1740",
"Id": "0x0",
"Permissions": "rwx",
"SignatureFile": "NINA-B22X-SI-4.0.0-003.txt"
}
]
Oduj9zhDz1QX+r2wnRmxy7m7d8SW5mkou9Xwph2cuifeOu7Rz8tU1E31cSyX4BSRE6uEnHFADPKo88yZT+7rAYo3W37b
5Q5pVE/zazwPq80tX4oJoROTmDItU9pj64Ygt84MqVsv+Aq576oDw/wjplSUnyc8apS5UjWacutQYSJNYtc5DV7kCjnM
ul75GxzWgiwOKiFYC8cutklHQyKbFvd/oHhwyZbllQNI5Z1J6FXcZg0lw+NdiUP85gR5nSIGngjew9iKHozLX90Zpj/2
kQtxRGbsGcGtWzJXVMtY+K+B9qAMBsmBx3NofACcB6vA3Gi3dPv+/L0ggiTf3fG6CQ==

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Procedure:
The examples in this procedure have been created and tested on EVK-NINA-B2 using TeraTerm.
1. Connect the supplied serial cable from the J8 connector on EVK-NINA-B2 to the USB port your
computer. For more information about setting up EVK-NINA-B2, see also EVK-NINA-B2 user
guide [4].
2. Download and unzip the latest u-connectXpress software from u-blox Product Resources.
3. Discover the COM port number for the USB Serial Port on your computer (MS Windows:
Start>Device Manager>Ports). See also “Setting up the evaluation board” in the EVK-NINA-B2
user guide [5].
Updating u-connectXpress connectivity software
Procedure:
The examples in this procedure have been created and tested on EVK-NINA-B2 using TeraTerm.
1. Setup the serial port connection as described in Setting up the serial port.
2. Enter Software version identification AT+GMR command to find out the current version of your
u-connectXpress software.
AT+GMR
"2.0.0-025"
OK

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3. Prepare the module to accept a binary file for download and start the bootloader at the
appropriate baud rate. Enter the Update software AT+UFWUPD command together with the
Connectivity Software values defined in the NINA-B22X-CF-<version>.json file and the signature
in the NINA-B22X-SI-x.x.x-xxx.txt file. The bootloader must be running when the software is
“sent” to the module in the next step. Note particularly that <mode>=0,
<name>=ConnectivitySoftware, and <flags>=rwx.
NINA-B2 returns a series of “C” characters for as long as the bootloader is running. The XMODEM
download is ready to begin from the host.
4. While the bootloader is running, send the u-connectXpress NINA-B22X-SW-4.0.0-0.003.bin file
to NINA-B2.
5. Once the binary file has been sent, NINA-B2 displays the greeting text +STARTUP. Enter the
Software version identification AT+GMR command again to make sure that the latest software
version is now installed.
For more information about the parameters, see the Software update +UFWUPD command in
u-connectXpress AT Commands Manual [1], u-connectXpress bootloader protocol specification [8],
and u-connectXpress user guide [5].
AT+UFWUPD=0,115200,0,651840,jzlRIkg37ir/pVpDKVrPot2ZdsaNvUtSYP2pDAUVJc7iQI9yzIo8VF
v8C1olP/9I4UJ4WmgC5oRay4AC0V8jRJSFFX/wop6x/sBJGOeDEu7yC/s0+Oj7CLs4TzNbiRqK0zLwKRiH
ohgVyzWqhwKFpmcxcDXphjkCTIvpffY8TwDLzkowuuD59R+sQCueJtBHBg9KDB3TOs8bsXLaVtT2x1rLfM
g8/pb+BPQEK9NcNB4hbp693ATivYE3cmxzWykIjEje819SIRGhHFt0wAsqh7WFgSJYNgDi5cLdOYz+r1+j
7+l4RqrMl/A/QYyWS9z0Q15QcJ3GlAJlXYa5v/ISjA==,nina-b2-debug,rwx
CCCCCCCCCCCCCCCCCCCCCCCCCC
+STARTUP
AT+GMR
"4.0.0-003"
OK

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3Design-in
3.1 Overview
For an optimal integration of NINA-B2 series modules in the final application board, it is recommended
to follow the design guidelines stated in this chapter. Every application circuit must be properly
designed to guarantee the correct functionality of the related interface; however, several points
require high attention during the design of the application device.
The following list provides important points sorted by rank of importance in the application design,
starting from the highest relevance:
1. Module antenna connection: Ant pad
Antenna circuit affects the RF compliance of the device integrating NINA-B221 modules with
applicable certification schemes. Follow the schematic and layout design recommendations
described in Antenna interface.
2. Module supply: VCC, VCC_IO, and GND pins
The supply circuit affects the performance of the device integrating NINA-B2 series module.
Follow the schematic and layout design recommendations described in Supply interfaces.
3. High speed interfaces: UART pins
High speed interfaces can be a source of radiated noise and can affect compliance with regulatory
standards for radiated emissions. Follow the schematic and layout design recommendations
described in Asynchronous serial interface (UART) design.
4. System functions: RESET_N, GPIO and other System input and output pins
Accurate design is required to guarantee that the voltage level is well defined during module boot.
Other pins: Accurate design is required to guarantee proper functionality.
3.2 Supply interfaces
Module supply (VCC) design
Good connection of the module’s VCC pin with DC supply source is required for correct RF
performance. The guidelines are summarized below:
•The VCC connection must be as wide and short as possible.
•The VCC connection must be routed through a PCB area separated from sensitive analog
signals and sensitive functional units. It is a good practice to interpose at least one layer of the
PCB ground between VCC track and other signal routing.
There is no strict requirement of adding bypass capacitance to the supply net close to the module.
But depending on the layout of the supply net and other consumers on the same net, bypass
capacitors might still be beneficial. Though the GND pins are internally connected, connect all the
available pins to solid ground on the application board, as a good (low impedance) connection to an
external ground can minimize power loss and improve RF and thermal performance.
Digital I/O interfaces reference voltage (VCC_IO)
Good connection of the module’s VCC_IO pin with DC supply source is required for correct
performance. The guidelines are summarized below:
•The VCC_IO connection must be as wide and short as possible.
•The VCC_IO connection must be routed through a PCB area separated from sensitive analog
signals and sensitive functional units. It is a good practice to interpose at least one layer of
PCB ground between VCC_IO track and other signal routing.

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There is no strict requirement of adding bypass capacitance to the supply net close to the module.
But depending on the layout of the supply net and other consumers on the same net, bypass
capacitors might still be beneficial. Though the GND pins are internally connected, connect all the
available pins to solid ground on the application board, as a good (low impedance) connection to an
external ground can minimize power loss and improve RF and thermal performance.
3.3 Antenna interface
As the unit cannot be mounted arbitrarily, the placement should be chosen with consideration so that
it does not interfere with radio communication. The NINA-B222 modules with an internal surface
mounted antenna cannot be mounted in a metal enclosure. No metal casing or plastics using metal
flakes should be used. Avoid metallic based paint or lacquer as well. The NINA-B222 modules offer
more freedom as an external antenna can be mounted further away from the module.
⚠According to the FCC regulations, the transmission line from the module’s antenna pin to the
antenna or antenna connector on the host PCB is considered part of the approved antenna
design. Therefore, module integrators must either follow exactly one of the antenna reference
design used in the module’s FCC type approval or certify their own designs.
RF transmission line design (NINA-B221 only)
RF transmission lines, such as the ones from the ANT pad up to the related antenna connector or up
to the related internal antenna pad, must be designed so that the characteristic impedance is as close
as possible to 50 Ω. Figure 5 shows the design options and the main parameters to be taken into
account when implementing a transmission line on a PCB:
•The microstrip (a track coupled to a single ground plane, separated by dielectric material)
•The coplanar microstrip (a track coupled to the ground plane and side conductors, separated
by dielectric material)
•The stripline (a track sandwiched between two parallel ground planes, separated by dielectric
material).
Figure 5: Transmission line trace design

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To properly design a 50 Ωtransmission line, the following remarks should be taken into account:
•The designer should provide enough clearance from surrounding traces and ground in the
same layer; in general, a trace to ground clearance of at least two times the trace width should
be considered, and the transmission line should be ‘guarded’ by a ground plane area on each
side.
•The characteristic impedance can be calculated as first iteration using tools provided by the
layout software. It is advisable to ask the PCB manufacturer to provide the final values that
are usually calculated using dedicated software and available stack-ups from production. It
could also be possible to request an impedance coupon on panel’s side to measure the real
impedance of the traces.
•FR-4 dielectric material, although its high losses at high frequencies can be considered in RF
designs provided that:
oRF trace length must be minimized to reduce dielectric losses.
oIf traces longer than few centimeters are needed, it is recommended to use a coaxial
connector and cable to reduce losses
oStack-up should allow for thick 50 Ωtraces and at least 200 µm trace width is
recommended to assure good impedance control over the PCB manufacturing process.
oFR-4 material exhibits poor thickness stability and thus less control of impedance over
the trace length. Contact the PCB manufacturer for specific tolerance of controlled
impedance traces.
•The transmission lines width and spacing to the GND must be uniform and routed as smoothly
as possible: route RF lines in 45 °C angle or in arcs.
•Add GND stitching vias around transmission lines.
•Ensure solid metal connection of the adjacent metal layer on the PCB stack-up to main ground
layer, providing enough vias on the adjacent metal layer.
•Route RF transmission lines far from any noise source (as switching supplies and digital lines)
and from any sensitive circuit to avoid crosstalk between RF traces and Hi-impedance or
analog signals.
•Avoid stubs on the transmission lines, any component on the transmission line should be
placed with the connected pad over the trace. Also avoid any unnecessary component on RF
traces.
Figure 6: Example of RF trace and ground design from NINA-B2 Evaluation Kit (EVK)

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Antenna design (NINA-B221)
Designers must take care of the antennas from all perspective at the beginning of the design phase
when the physical dimensions of the application board are under analysis/decision, as the RF
compliance of the device integrating NINA-B2 module with all the applicable required certification
schemes heavily depends on the radiating performance of the antennas. The designer is encouraged
to consider one of the u-blox suggested antenna part numbers and follow the layout requirements.
•External antennas such as linear monopole:
oExternal antennas basically do not imply physical restriction to the design of the PCB
where the module is mounted.
oThe radiation performance mainly depends on the antennas. It is required to select
antennas with optimal radiating performance in the operating bands.
oRF cables should be carefully selected with minimum insertion losses. Additional insertion
loss will be introduced by low quality or long cable. Large insertion loss reduces radiation
performance.
oA high quality 50 Ωcoaxial connector provides proper PCB-to-RF-cable transition.
•Integrated antennas such as patch-like antennas:
oInternal integrated antennas imply physical restriction to the PCB design:
Integrated antenna excites RF currents on its counterpoise, typically the PCB ground
plane of the device that becomes part of the antenna; its dimension defines the minimum
frequency that can be radiated. Therefore, the ground plane can be reduced down to a
minimum size that should be similar to the quarter of the wavelength of the minimum
frequency that has to be radiated, given that the orientation of the ground plane related
to the antenna element must be considered.
The RF isolation between antennas in the system has to be as high as possible and the
correlation between the 3D radiation patterns of the two antennas has to be as low as
possible. In general, an RF separation of at least a quarter wavelength between the two
antennas is required to achieve a maximum isolation and low pattern correlation;
increased separation should be considered, if possible, to maximize the performance and
fulfil the requirements in Table 5.
As a numerical example, the physical restriction to the PCB design can be considered as
shown below:
Frequency = 2.4 GHz Wavelength = 12.5 cm Quarter wavelength = 3.125 cm1
oRadiation performance depends on the whole product and antenna system design,
including product mechanical design and usage. Antennas should be selected with
optimal radiating performance in the operating bands according to the mechanical
specifications of the PCB and the whole product.
1Wavelength referred to a signal propagating over the air.