UG531: BRD4191A BG22 Direction Finding
Radio Board User's Guide
A Wireless Pro Kit with the BRD4191A BG22 Direction Finding
Radio Board enables developers to develop RF-based Real-Time
Locationing Systems and applications, utilizing the protocol level
support of Angle of Arrival (AoA) and Angle of Departure (AoD) in
Bluetooth 5. The board contains a 2.4 GHz EFR32BG22 Wireless
Gecko System-on-Chip, and an antenna array optimized for accurate direction finding performance.
The BRD4191A can be connected to the Wireless Starter Kit Mainboard (BRD4001A)
and the Wireless Pro Kit Mainboard (BRD4002A) through a BRD8010B STK/WSTK Debug Adapter board, and a Mini Simplicity+ cable. It is a complete HW design for the
EFR32BG22 Wireless SoC, with matching network, UFL connector and an antenna array
for 6 dBm output power in the 2.4 GHz band.
The mainboards contain an on-board J-Link debugger with a Packet Trace Interface and
a Virtual COM port, enabling application development and debugging of the connected
radio board as well as external hardware. The mainboard also contains sensors and peripherals for easy demonstration of some of the EFR32's many capabilities, but due to
the limited connectivity options of the Mini Simplicity+ interface, utilizing those peripherals with the BRD4191A is not supported.
This document describes how to use the BRD4191A BG22 Direction Finding Radio
Board together with a Wireless Starter Kit Mainboard or a Wireless Pro Kit Mainboard.
BRD4191A RADIO BOARD FEATURES
• EFR32 Wireless Gecko SoC with 512 kB
Flash and 32 kB RAM
(EFR32BG22C224F512IM40).
• Direction Finding Antenna Array (2.4 GHz
band)
• Mini Simplicity+ connector
• UFL connector (optional)
WIRELESS STK MAINBOARD FEATURES
• Advanced Energy Monitor
• Packet Trace Interface
• Virtual COM port
• SEGGER J-Link on-board debugger
• External device debugging
• Ethernet and USB connectivity
• Silicon Labs Si7021 relative humidity and
temperature sensor (not connected to
BRD4191A)
• Low power 128x128 pixel Memory LCDTFT (not connected to BRD4191A)
• User LEDs / pushbuttons (not connected
to BRD4191A)
• 20-pin 2.54 mm EXP header (not
connected to BRD4191A)
• Breakout pads for SoC I/O (not connected
to BRD4191A)
• CR2032 coin cell battery support
SOFTWARE SUPPORT
• Simplicity Studio™
• Energy Profiler
• Network Analyzer
ORDERING INFORMATION
• BG22-RB4191A
silabs.com | Building a more connected world.
Copyright © 2022 by Silicon Laboratories
Rev. 1.0-p27
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1 Radio Boards
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1.2 Mainboards .
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. 5
1.3 Ordering Information .
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. 6
1.4 Getting Started .
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. 6
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2. Hardware Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.1 Hardware Layout .
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. 7
2.2 Block Diagram .
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. 8
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3. Mainboard Connectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.1 J-Link USB Connector
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. 9
3.2 Ethernet Connector .
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.10
3.3 Debug Adapter .
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.10
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4. Radio Board Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.1 Breakout Pads .
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.12
4.2 Mini Simplicity+ Connector .
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.13
5. Power Supply and Reset . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.1 Radio Board Power Selection .
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.14
5.2 Kit Power . . . . . . .
5.2.1 Board Controller Power
5.2.2 AEM Power . . . .
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.15
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5.3 EFR32BG22 Reset
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.15
6. Peripherals
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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
6.1 Serial Flash (Not Mounted) .
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.16
6.2 Virtual COM Port . . .
6.2.1 Host Interfaces . .
6.2.2 Serial Configuration .
6.2.3 Hardware Handshake
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.17
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7. Board Controller
7.1 Introduction .
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.20
7.2 Admin Console . . . .
7.2.1 Connecting . . . .
7.2.2 Built-in Help . . .
7.2.3 Command Examples
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.20
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.21
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7.3 Virtual UART . .
7.3.1 Target to Host .
7.3.2 Host to Target .
7.3.3 Limitations . .
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.21
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silabs.com | Building a more connected world.
Rev. 1.0-p27 | 2
7.3.4 Troubleshooting .
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8. Advanced Energy Monitor
8.1 Introduction .
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.22
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.23
8.2 Code Correlation .
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.23
8.3 AEM Circuit . . .
8.3.1 AEM Details .
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.23
.24
9. On-Board Debugger . . . . . . . . . . . . . . . . . . . . . . . . . . . .
25
9.1 Host Interfaces . . . . . .
9.1.1 USB Interface . . . . .
9.1.2 Ethernet Interface . . .
9.1.3 Serial Number Identification
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.25
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9.2 Debug Mode.
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.25
9.3 Debugging During Battery Operation
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.26
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10. Radio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
10.1 RF Section . . . . . . . . .
10.1.1 Description of the RF Matching
10.1.2 RF Section Power Supply . .
10.1.3 RF Matching Bill of Materials .
10.1.4 Antenna . . . . . . . .
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.27
.27
.27
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10.3 Conducted Power Measurements . . . . . . . . . . .
10.3.1 Conducted Power Measurements with Unmodulated Carrier .
10.3.2 Relaxation with Modulated Carrier . . . . . . . . .
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.28
.28
.29
10.4 Radiated Power Measurements . . . . . . . . . . . .
10.4.1 Maximum Radiated Power Measurement . . . . . . .
10.5.1 Recommendations for 2.4 GHz ETSI EN 300-328 Compliance
10.5.2 Recommendations for 2.4 GHz FCC 15.247 Compliance . .
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.29
.30
.30
.30
11. Kit Configuration and Upgrades . . . . . . . . . . . . . . . . . . . . . . . 31
11.1 Firmware Upgrades .
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12. Schematics, Assembly Drawings, and BOM
13. Kit Revision History and Errata
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.31
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13.1 Revision History .
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13.2 Errata
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.33
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14. Board Revision History and Errata . . . . . . . . . . . . . . . . . . . . . . 34
14.1 Revision History .
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.34
14.2 Errata
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.34
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15. Document Revision History
silabs.com | Building a more connected world.
. . . . . . . . . . . . . . . . . . . . . . . . 35
Rev. 1.0-p27 | 3
UG531: BRD4191A BG22 Direction Finding Radio Board User's Guide
Introduction
1. Introduction
The EFR32BG22 Wireless Gecko System-on-Chip is featured on the that plugs into a Wireless Pro Kit (WPK) Mainboard. The mainboard features several tools for easy evaluation and development of wireless applications. An on-board J-Link debugger enables programming and debugging on the target device over USB or Ethernet. The Advanced Energy Monitor (AEM) offers real-time current and
voltage monitoring. A virtual COM port interface (VCOM) provides an easy-to-use serial port connection over USB or Ethernet. The
Packet Trace Interface (PTI) offers invaluable debug information about transmitted and received packets in wireless links.
All debug functionality, including AEM, VCOM, and PTI, can also be used towards external target hardware instead of a radio board
attached directly to the mainboard through the 2x40-pin connectors.
To further enhance its usability, the mainboard contains sensors and peripherals that demonstrate some of the many capabilities of the
EFR32BG22. The mainboard also has a 20-pin EXP header which can be used for connecting EXP boards to the kit or for easy connection to I/Os on the target IC on the radio board.
1.1 Radio Boards
A Wireless Pro Kit consists of one or more mainboards and radio boards that plug into the mainboard. Different radio boards are available, each featuring different Silicon Labs devices with different operating frequency bands. Because the mainboards are designed to
work with different radio boards, the actual pin mapping from a device pin to a mainboard feature is done on the radio board. This
means that each radio board has its own pin mapping to the Wireless Pro Kit features, such as buttons, LEDs, the display, the EXP
header and the breakout pads. Because this pin mapping is different for every radio board, it is important to consult the correct document, which shows the kit features in context of the radio board plugged in.
silabs.com | Building a more connected world.
Rev. 1.0-p27 | 4
UG531: BRD4191A BG22 Direction Finding Radio Board User's Guide
Introduction
1.2 Mainboards
The BG22 Direction Finding Radio Board (BRD4191A) can be used with either a Wireless Starter Kit Mainboard (BRD4001A) or a Wireless Pro Kit Mainboard (BRD4002A). The Wireless Pro Kit Mainboard is the successor to the Wireless Starter Kit Mainboard, which
comes with some improvements and added features including increased AEM measurement range and sample rate, variable VMCU
voltage, joystick, and a Mini Simplicity Connector. Kit features, such as the Si7021 sensor and the EXP header, are available on the
same EFR32 pins regardless of the mainboard being used, but the pinout to the breakout pads differs. The combination of the BG22
Direction Finding Radio Board with either one of these mainboards is hereby referred to as a Wireless Pro Kit as the figure below illustrates.
BG22 Dual Polarized Antenna Array
Radio Board (BRD4191A)
STK/WSTK Debug Adapter
Board with Simplicity Mini+
Connector (BRD8010B)
+
Mini Simplicity+ Cable
+
+
Wireless Pro Kit
Mainboard (BRD4002A)
Wireless Starter Kit
Mainboard (BRD4001A)
=
=
+
1
Wireless Pro Kit
1
Figure 1.1. Wireless Pro Kit Combinations
Note: This document explains how to use the Wireless Pro Kit when the BG22 Direction Finding Radio Board (BRD4191A) is combined
with either a Wireless Starter Kit Mainboard (BRD4001A) or a Wireless Pro Kit Mainboard (BRD4002A). Since some of the functionality
silabs.com | Building a more connected world.
Rev. 1.0-p27 | 5
UG531: BRD4191A BG22 Direction Finding Radio Board User's Guide
Introduction
of the kit depends on the type of mainboard used, it is important to consult the right information in the user guide whenever there are
discrepancies.
1.3 Ordering Information
BRD4191A can be obtained as a separate radio board, BG22-RB4191A.
Table 1.1. Ordering Information
Part Number
Description
BG22-RB4191A BG22 Direction Finding Radio
Board
Contents
1x BRD4191A BG22 Direction Finding Radio Board
1x BRD8010B STK/WSTK Debug Adapter Board with Simplicity Mini+ Connector
1x 12-pin Mini Simplicity+ Ribbon Cable
BG22-PK6022A BG22 Direction Finding Pro Kit
1x BRD4191A BG22 Direction Finding Radio Board
1x BRD8010B STK/WSTK Debug Adapter Board with Simplicity Mini+ Connector
1x 12-pin Mini Simplicity+ Ribbon Cable
1x BRD4002A Wireless Pro Kit Mainboard
1.4 Getting Started
Detailed instructions for how to get started can be found on the Silicon Labs web pages: silabs.com/development-tools.
silabs.com | Building a more connected world.
Rev. 1.0-p27 | 6
UG531: BRD4191A BG22 Direction Finding Radio Board User's Guide
Hardware Overview
2. Hardware Overview
2.1 Hardware Layout
The layout of the BG22 Direction Finding Wireless Pro Kit when the radio board is combined with a Wireless Pro Kit Mainboard
(BRD4002A) or a Wireless STK Mainboard (BRD4001A) is shown below.
On-board USB and Ethernet
J-Link Debugger
- Virtual COM Port
- Packet-trace
- Advanced Energy
Monitoring
Radio Board
Breakout Pads
Logic Analyzer
(Planned feature)
Ultra-low power
128x128 pixel
memory LCD
(Not connected
to BRD4191A)
Joystick
(Not connected
to BRD4191A)
EXP-header
for expansion
boards
Si7021
Humidity
and
Temperature
Sensor
Battery or
USB power Buttons and LEDs
(Not connected
to BRD4191A)
Mini Simplicity
Connector
Simplicity Connector
Debug Adapter Board
with Mini Simplicity+
Connector (BRD8010B)
Breakout Pads
Direction Finding Antenna Array
ARM Coresight 19-pin
Trace/debug Header
12-pin Ribbon Cable
BG22 Direction Finding
Radio Board
(BRD4191A, Top Side)
Figure 2.1. Hardware Layout With A Wireless Pro Kit Mainboard (BRD4002A)
On-board USB and Ethernet
J-Link Debugger
- Virtual COM Port
- Packet-trace
- Advanced Energy
Monitoring
Radio Board
Breakout Pads
Battery or
USB power
Ultra-low power
128x128 pixel
memory LCD
(Not connected
to BRD4191A)
Buttons and LEDs
(Not connected
to BRD4191A)
Si7021
Humidity
and
Temperature
Sensor
EXP-header
for expansion
boards
Simplicity Connector
Debug Adapter Board
with Mini Simplicity+
Connector (BRD8010B)
Breakout Pads
Direction Finding Antenna Array
ARM Coresight 19-pin
Trace/debug Header
12-pin Ribbon Cable
BG22 Direction Finding
Radio Board
(BRD4191A, Top Side)
Figure 2.2. Hardware Layout With A Wireless STK Mainboard (BRD4001A)
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UG531: BRD4191A BG22 Direction Finding Radio Board User's Guide
Hardware Overview
2.2 Block Diagram
An overview of the BG22 Direction Finding Wireless Pro Kit is shown in the figure below.
USB
Connector
Debug
Packet Trace
UART
AEM
Board
Controller
RJ-45 Ethernet
Connector
Debug
Packet Trace
AEM
UART
Mini Simplicity+
Connector
UART
Breakout Pads
SW CTRL
SW CTRL
Optional
8 Mbit
MX25R
2.4 GHz RF
SPI
Serial Flash
EFR32BG22
Wireless SoC
RF Switches
& Antenna
Array
Figure 2.3. Kit Block Diagram
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UG531: BRD4191A BG22 Direction Finding Radio Board User's Guide
Mainboard Connectors
3. Mainboard Connectors
This chapter gives you an overview of the mainboard connectivity. The placement of the connectors on the Wireless Pro Kit Mainboard
(BRD4002A) and the Wireless STK Mainboard (BRD4001A) is shown below.
5V GND P25 P27 P29 P31 P33 P35 P37 P39 P41 P43 P45 F20 GND 3V3 Rad
5V GND P24 P26 P28 P30 P32 P34 P36 P38 P40 P42 P44 F19 GND 3V3 Co io B
nn
ec oard
tor
s
t
e
rn tor
e
h
c
32
2
Lo
Et nne
31
1
Co gic A
Co
(Pl nne nal
y
c
an
ne tor zer
dF
B
S
e
U
atu
re)
ink tor
J-L nnec
o
C
EXP Header
P101
VMCU GND F1
VMCU GND F0
F3
F2
F5
F4
2
32
1
31
F7
F6
F9
F8
Mini Simplicty
Connector
1
F11 F13 P15 P17 P19 P21 P23 GND VRF
F10 F12 P14 P16 P18 P20 P22 GND VRF
Debug
Connector
Simplicity
Connector
Figure 3.1. Wireless Pro Kit Mainboard (BRD4002A) Connector Layout
5V GND P25 P27 P29 P31 P33 P35 P37 P39 P41 P43 P45
5V GND P24 P26 P28 P30 P32 P34 P36 P38 P40 P42 P44
NC GND 3V3
NC GND 3V3
Ra
Co dio B
nn
ec oard
tor
s
et
ern ctor
h
t
E nne
Co
EX
PH
ea
de
B
US
nk ctor
i
L
J- nne
Co
r
Sim
Co plic
nn ity
ec
tor
De
Co bug
nn
ec
tor
VMCU GND P1
VMCU GND P0
P3
P2
P5
P4
P7
P6
P9
P8
P11 P13 P15 P17 P19 P21 P23 GND VRF
P10 P12 P14 P16 P18 P20 P22 GND VRF
Figure 3.2. Wireless STK Mainboard (BRD4001A) Connector Layout
3.1 J-Link USB Connector
The J-Link USB connector is situated on the left side of the Wireless STK Mainboard. Most of the kit's development features are supported through this USB interface when connected to a host computer. Such features include:
• Debugging and programming of the target device using the on-board J-Link debugger
• Communication with the target device over the virtual COM port using USB-CDC
• Accurate current profiling using the AEM
In addition to providing access to development features of the kit, this USB connector is also the main power source for the kit. USB 5V
from this connector powers the board controller and the AEM. It is recommended that the USB host be able to supply at least 500 mA
to this connector, although the actual current required will vary depending on the application.
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UG531: BRD4191A BG22 Direction Finding Radio Board User's Guide
Mainboard Connectors
3.2 Ethernet Connector
The Ethernet connector provides access to all of the Wireless STK's development features over TCP/IP. The Ethernet interface provides some additional development features to the user. Supported features include:
•
•
•
•
•
•
Debugging and programming of the target device using the on-board J-Link debugger
Communication with the target device over the virtual COM port using TCP/IP socket 4901
"VUART" communication with the target device over the debug SWD/SWO interface using TCP/IP socket 4900
Accurate current profiling using the AEM
Real-time radio packet and network analysis using the Packet Trace Interface
Access to advanced configuration options using the admin console over TCP/IP socket 4902
Note: The Wireless STK cannot be powered using the Ethernet connector, so to use this interface, the USB connector must be used to
provide power to the board.
3.3 Debug Adapter
The BRD8010B STK/WSTK Debug Adapter is an adapter board which plugs directly into the debug connector and the Simplicity Connector on the mainboard. It combines selected functionality from the two connectors to smaller footprint 10 and 12-pin connectors,
which are more suitable for space-constrained designs.
For versatility, the debug adapter features three different debug connectors:
• 12-pin Silicon Labs Mini Simplicity+ Connector
• 10-pin ARM Cortex 10-pin Debug Connector (not mounted)
• 10-pin Silicon Labs ISA3 Packet Trace (not mounted)
The ARM Cortex 10-pin Debug Connector follows the standard Cortex pinout defined by ARM and allows the Wireless Pro Kit to be
used to debug hardware designs that use this connector.
The ISA3 connector follows the same pinout as the Packet Trace connector found on the Silicon Labs Ember Debug Adapter (ISA3).
This enables using the Wireless Pro Kit to debug hardware designs that use this connector.
The Mini Simplicity+ Connector is designed to offer advanced debug features from the kit on a 12-pin connector. The connector has the
same pinout and functionality as described in 4.2 Mini Simplicity+ Connector.
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UG531: BRD4191A BG22 Direction Finding Radio Board User's Guide
Radio Board Connectors
4. Radio Board Connectors
The Wireless Pro Kit features a Mini Simplicity+ connector, and 13 breakout pads. The Mini Simplicity+ connector is placed on the bottom side of the board, the placements and the breakout pads pinout are shown in the figure below. For additional information on the
connectors, see the following sub chapters.
Breakout Pads
VMCU
GND
PA05 - VCOM_TX
PA06 - VCOM_RX
PA07 - VCOM_RTS
PA08 - VCOM_CTS
PC00 - CTRL1
PC01 - CTRL2
PC02 - CTRL3
PC03 - CTRL4
Mini Simplicity+
Connector
PC04 - CTRL5
PC05 - CTRL6
PC06 - CTRL7
Figure 4.1. Wireless Pro Kit Connectors (Bottom Side)
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UG531: BRD4191A BG22 Direction Finding Radio Board User's Guide
Radio Board Connectors
4.1 Breakout Pads
Twenty breakout pads are provided and allow connection of external peripherals. There are 10 pads on the left side of the board, and
10 pads on the right. The breakout pads contain a number of I/O pins that can be used with most of the EFR32BG22 Wireless Gecko's
features. Additionally, the VMCU (main board power rail), 3V3 (LDO regulator output), and 5V power rails are also exposed on the
pads.
The pin-routing on the Wireless Gecko is very flexible, so most peripherals can be routed to any pin. However, pins may be shared
between the breakout pads and other functions on the Wireless Pro Kit. The table below includes an overview of the breakout pads and
functionality that is shared with the kit.
Table 4.1. Breakout Pads Pinout
Pin
Connection
Shared Feature
1
VMCU
Target voltage on the debugged application. Supplied and monitored by the
AEM when powered by a Wireless STK with its power selection switch in
the "AEM" position.
2
GND
Ground
3
PA05
Virtual COM TX
4
PA06
Virtual COM RX
5
PA07
Virtual COM RTS
6
PA08
Virtual COM Port CTS
7
PC00
RF Switch Control Signal 1
8
PC01
RF Switch Control Signal 2
9
PC02
RF Switch Control Signal 3
10
PC03
RF Switch Control Signal 4
11
PC04
RF Switch Control Signal 5
12
PC05
RF Switch Control Signal 6
12
PC06
RF Switch Control Signal 7
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UG531: BRD4191A BG22 Direction Finding Radio Board User's Guide
Radio Board Connectors
4.2 Mini Simplicity+ Connector
The Mini Simplicity+ connector featured on the Wireless Pro Kit is a 12-pin 1.27 mm pitch connector that allows the use of an external
debugger such as the one found on a Silicon Labs Wireless Pro Kit (WPK) Mainboard. In addition to providing serial wiredebug (SWD)
and virtual COM port functionality with flow control, the WPK can also support advanced energy profiling, wireless network analysis and
debugging tools.
The Mini Simplicity+ connector pinout is illustrated in the figure below.
VMCU
RESET
VCOM_TX
SWDIO
PTI_FRAME
VCOM_CTS
1
3
5
7
9
11
2
4
6
8
10
12
GND
VCOM_RX
SWO
SWCLK
PTI_DATA
VCOM_RTS
Figure 4.2. Mini Simplicity+ Connector
Note: Current drawn from the VMCU voltage pin is included in the AEM measurements. When monitoring the current consumption of
the Wireless Pro Kit with the AEM, unplug any radio board from the WPK Mainboard to avoid adding the radio board's current consumption to the measurements.
Table 4.2. Mini Simplicity+ Connector Pin Descriptions
Pin Number(s)
Function
Connection
Description
1
AEM
VMCU
2
GND
GND
3
RST
RESET
4
VCOM_RX
PA06
Virtual COM Rx
5
VCOM_TX
PA05
Virtual COM Tx
6
SWO
PA03
Serial Wire Output
7
SWDIO
PA02
Serial Wire Data
8
SWCLK
PA01
Serial Wire Clock
9
PTI_FRAME
PD03
Packet Trace Frame
10
PTI_DATA
PD02
Packet Trace Data
11
VCOM_CTS
PA08
Virtual COM Port CTS
12
VCOM_RTS
PA07
Virtual COM Port RTS
Target voltage on the debugged application. May be supplied and
monitored by the AEM on an external debugger.
Ground
EFR32BG22 reset
Note: Mini Simplicity+ Connector pin-out is referenced from the device target side.
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UG531: BRD4191A BG22 Direction Finding Radio Board User's Guide
Power Supply and Reset
5. Power Supply and Reset
5.1 Radio Board Power Selection
The EFR32BG22 on a Wireless Pro Kit can be powered by one of these sources:
• The debug USB cable
• A 3 V coin cell battery
• A USB regulator on the radio board (for devices with USB support only)
PO
S3
PO
S2
PO
S1
The power source for the radio board is selected with the slide switch in the lower left corner of the Wireless STK Mainboard or the
Wireless Pro Kit Mainboard. The figure below shows how the different power sources can be selected with the slide switch.
USB
Connector
5V
LDO
VOUT
Advanced
Energy
Monitor
POS1
POS2
VMCU
POS3
EFR32
3 V Lithium Battery
(CR2032)
Figure 5.1. Power Switch
Note: The middle position is denoted by "USB" on the Wireless STK Mainboard, while it is denoted by "SELF" on the Wireless Pro Kit
Mainboard. The slide switch functions the same on both mainboards.
Note: The AEM can only measure the current consumption of the EFR32BG22 when the power selection switch is in the AEM position.
AEM position: With the switch in the AEM position, a low noise LDO on the mainboard is used to power the radio board. This LDO is
again powered from the debug USB cable. The AEM is now also connected in series, allowing accurate high speed current measurements and energy debugging/profiling.
USB position: With the switch in the USB position, radio boards with USB-support can be powered by a regulator on the radio board
itself. BRD4191A does not contain a USB regulator, and setting the switch in the USB position will cause the EFR32BG22 to be unpowered.
BAT position: With the switch in the BAT position, a 20 mm coin cell battery in the CR2032 socket can be used to power the device.
With the switch in this position, no current measurements are active. This is the switch position that should be used when the radio
board is powered with an external power source. The Wireless Pro Kit Mainboard (BRD4002A) features an additional 2-pin JST connector connected in paralell to the CR2032 socket that can be used with an external power source between 1.8 V and 3.6 V instead of
a coin cell. The coin cell battery is not protected from reverse current, and it is therefore important to remove the coin cell battery from
the CR2032 socket if applying external power.
Note: The current sourcing capabilities of a coin cell battery might be too low to supply certain wireless applications.
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UG531: BRD4191A BG22 Direction Finding Radio Board User's Guide
Power Supply and Reset
5.2 Kit Power
There are normally two main contributions to the power consumption from the mainboard USB connector, i.e., two main current paths:
• One being monitored by the AEM that goes to the target power domain (VMCU)
• One that goes to the board controller power domain
While the current consumption of the board controller section is fairly deterministic and stable, the current consumption connected to
the target’s power domain (VMCU) varies widely depending on the application and the slide switch position. Typically, the board controller power domain draws 200 mA on the Wireless Starter Kit Mainboard (BRD4001A) and 250 mA on the Wireless Pro Kit Mainboard
(BRD4002A). The mainboards use linear regulators, and the recommended input voltage is 4.4 - 5.25 V. Use a USB host or power
supply and cables that can deliver at least the total amount of current required by the kit.
The 5V net exposed on the breakout pads, EXP header and radio board is also sourced from the mainboard USB connector when the
power select switch is in the AEM position. The 3V3 net exposed on the same peripherals is always sourced from the mainboard USB
connector. The current consumption of these nets must be included in the total current consumption of the kit if these are utilized.
5.2.1 Board Controller Power
The board controller is responsible for important features, such as the debugger and the AEM, and is powered exclusively through the
USB port in the top left corner of the board. This part of the kit resides on a separate power domain, so a different power source can be
selected for the target device while retaining debugging functionality. This power domain is also isolated to prevent current leakage
from the target power domain when power to the board controller is removed.
The board controller power domain is not influenced by the position of the power switch.
The kit has been carefully designed to keep the board controller and the target power domains isolated from each other as one of them
powers down. This ensures that the target EFR32BG22 device will continue to operate in the BAT mode.
5.2.2 AEM Power
The supply for the target power domain (VMCU) is a linear regulator integrated with the AEM described in Section when the power
select switch is in the AEM position. The output voltage of the regulator is fixed to 3.3 V on the Wireless STK Mainboard (BRD4001A),
while it can be adjusted between 1.8 V and 3.6 V on the Wireless Pro Kit Mainboard (BRD4002A) using the .
The output current on the Wireless Pro Kit Mainboard (BRD4002A) is limited by an overcurrent protection (OCP) function, which depends on the programmed VMCU voltage: OCP (A) ≈ VMCUSET (V) x 0.2 (A/V). Approaching or exceeding the OCP limit is not recommended as the output voltage will be pulled low, which causes loss of function.
The maximum recommended output current on the Wireless STK Mainboard (BRD4001A) is 300 mA.
5.3 EFR32BG22 Reset
The EFR32BG22 SoC can be reset by a few different sources:
• A user pressing the RESET button
• The on-board debugger pulling the #RESET pin low
• An external debugger pulling the #RESET pin low
In addition to the reset sources mentioned above, a reset to the EFR32BG22 will also be issued during board controller boot-up. This
means that removing power to the board controller (unplugging the J-Link USB cable) will not generate a reset but plugging the cable
back in will as the board controller boots up.
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UG531: BRD4191A BG22 Direction Finding Radio Board User's Guide
Peripherals
6. Peripherals
The Wireless Pro Kit has a set of peripherals that showcase some of the EFR32BG22 features.
6.1 Serial Flash (Not Mounted)
The BRD4191A Radio Board has an option to mount an 8 Mbit Macronix MX25R SPI flash that is connected directly to the
EFR32BG22. The figure below shows how the serial flash is connected to the EFR32BG22.
VMCU
VDD
PB02 (US0_CLK)
SCLK
PB00 (US0_TX)
MOSI
PB01 (US0_RX)
MISO
PA00 (GPIO)
SCS
8 Mbit
MX25R8035F
EFR32
Figure 6.1. Radio Board Serial Flash
The MX25R series are ultra low power serial flash devices, so there is no need for a separate enable switch to keep current consumption down. However, it is important that the flash is always put in deep power down mode when not used. This is done by issuing a
command over the SPI interface. In deep power down, the MX25R typically adds approximately 100 nA to the radio board current consumption.
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UG531: BRD4191A BG22 Direction Finding Radio Board User's Guide
Peripherals
6.2 Virtual COM Port
An asynchronous serial connection to the board controller is provided for application data transfer between a host PC and the target
EFR32BG22. This eliminates the need for an external serial port adapter.
Isolation & Level Shift
PA05 (US1_TX)
PA06 (US1_RX)
PA08 (US1_CTS)
PA07 (US1_RTS)
VCOM_TX
VCOM_RX
Board
Controller
VCOM_CTS
USB
or
ETH
Host
PC
VCOM_RTS
pin_vcom_enable
EFR32
VCOM_ENABLE
Figure 6.2. Virtual COM Port Interface
The virtual COM port consists of a physical UART between the target device and the board controller and a logical function in the board
controller that makes the serial port available to the host PC over USB or Ethernet. The UART interface consists of four pins and an
enable signal.
Table 6.1. Virtual COM Port Interface Pins
Signal
Description
VCOM_TX
Transmit data from the EFR32BG22 to the board controller
VCOM_RX
Receive data from the board controller to the EFR32BG22
VCOM_CTS
Clear to Send hardware flow control input, asserted by the board controller when it is ready to receive more data
VCOM_RTS
Request to Send hardware flow control output, asserted by the EFR32BG22 when it is ready to receive more data
VCOM_ENABLE Enables the VCOM interface, allowing data to pass through to the board controller
The parameters of the serial port, such as baud rate or flow control, can be configured using the . The default settings depend on which
radio board is used with the mainboard.
Note: The VCOM port is only available when the board controller is powered, which requires the J-Link USB cable to be inserted.
Note: There may be slight differences on the terminal prompt and settings between the Wireless Starter Kit Mainboard and the Wireless Pro Kit Mainboard.
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UG531: BRD4191A BG22 Direction Finding Radio Board User's Guide
Peripherals
6.2.1 Host Interfaces
Data can be exchanged between the board controller and the target device through the VCOM interface, which is then available to the
user in two different ways:
• Virtual COM port using a standard USB-CDC driver
• TCP/IP by connecting to the Wireless STK on TCP/IP port 4901 with a Telnet client
When connecting via USB, the device should automatically show up as a COM port. The actual device name that is associated with the
kit depends on the operating system and how many devices are or have been connected previously. The following are examples of
what the device might show up as:
• JLink CDC UART Port (COM5) on Windows hosts
• /dev/cu.usbmodem1411 on macOS
• /dev/ttyACM0 on Linux
Data sent by the target device into the VCOM interface can be read from the COM port, and data written to the port is transmitted to the
target device. Connecting to the Wireless STK on port 4901 gives access to the same data over TCP/IP. Data written into the VCOM
interface by the target device can be read from the socket, and data written into the socket is transmitted to the target device.
Note: Only one of these interfaces can be used at the same time, with the TCP/IP socket taking priority. This means that if a socket is
connected to port 4901, no data can be sent or received on the USB COM port.
6.2.2 Serial Configuration
By default, the VCOM serial port is configured to use 115200 8N1 (115.2 kbit/s, 8 data bits, 1 stop bit), with flow control disabled/ignored. The configuration can be changed using the admin console:
WPK> serial vcom config
Usage: serial vcom config [--nostore] [handshake ] [speed ]
Using this command, the baud rate can be configured between 9600 and 921600 bit/s, and hardware handshake can be enabled or
disabled on either or both flow control pins.
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UG531: BRD4191A BG22 Direction Finding Radio Board User's Guide
Peripherals
6.2.3 Hardware Handshake
The VCOM peripheral supports basic RTS/CTS flow control.
VCOM_CTS (target clear to send) is a signal that is output from the board controller and input to the target device. The board controller
de-asserts this pin whenever its input buffer is full and it is unable to accept more data from the target device. If hardware handshake is
enabled in the target firmware, its UART peripheral will halt when data is not being consumed by the host. This implements end-to-end
flow control for data moving from the target device to the host.
VCOM_CTS is connected to the RTS pin on the board controller and is enabled by setting handshake to either RTS or RTSCTS using
the "serial vcom config" command.
VCOM_RTS (target request to send) is a signal that is output from the target device and input to the board controller. The board controller will halt transmission of data towards the target if the target device de-asserts this signal. This gives the target firmware a means
to hold off incoming data until it can be processed. Note that de-asserting RTS will not abort the byte currently being transmitted, so the
target firmware must be able to accept at least one more character after RTS is de-asserted.
VCOM_RTS is connected to the CTS pin of the board controller. It is enabled by setting handshake to either CTS or RTSCTS using the
"serial vcom config" command in the admin console. If CTS flow control is disabled, the state of VCOM_RTS will be ignored and data
will be transmitted to the target device anyway.
Table 6.2. Hardware Handshake Configuration
Mode
Description
disabled
RTS (VCOM_CTS) is not driven by the board controller and CTS (VCOM_RTS) is ignored.
rts
RTS (VCOM_CTS) is driven by the board controller to halt target from transmitting when input buffer is full. CTS
(VCOM_RTS) is ignored.
cts
RTS (VCOM_CTS) is not driven by the board controller. Data is transmitted to the target device if CTS
(VCOM_RTS) is asserted and halted when de-asserted.
rtscts
RTS (VCOM_CTS) is driven by the board controller to halt target when buffers are full. Data is transmitted to the
target device if CTS (VCOM_RTS) is asserted and halted when de-asserted.
Note: Enabling CTS flow control without configuring the VCOM_RTS pin can result in no data being transmitted from the host to the
target device.
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UG531: BRD4191A BG22 Direction Finding Radio Board User's Guide
Board Controller
7. Board Controller
The Wireless STK Mainboard contains a dedicated microcontroller for some of the advanced kit features provided. This microcontroller
is referred to as the board controller and is not programmable by the user. The board controller acts as an interface between the host
PC and the target device on the radio board, as well as handling some housekeeping functions on the board.
Some of the kit features actively managed by the board controller are
•
•
•
•
•
The on-board debugger, which can flash and debug both on-board and external targets.
The Advanced Energy Monitor, which provides real-time energy profiling of the user application.
The Packet Trace Interface, which is used in conjunction with PC software to provide detailed insight into an active radio network.
The Virtual COM Port and interfaces, which provide ways to transfer application data between the host PC and the target processor.
The admin console, which provides configuration of the various board features.
Silicon Labs publishes updates to the board controller firmware in the form of firmware upgrade packages. These updates may enable
new features or fix issues. See Section for details on firmware upgrade.
7.1 Introduction
The Wireless STK Mainboard and the Wireless Pro Kit Mainboard contain a dedicated microcontroller for some of the advanced kit
features provided. This microcontroller is referred to as the board controller and is not programmable by the user. The board controller
acts as an interface between the host PC and the target device on the radio board, as well as handling some housekeeping functions
on the board.
Note: This chapter describes the board controller on both the Wireless Starter Kit Mainboard and the Wireless Pro Kit Mainboard.
There might be slight differences between these two boards, such as the exact menu and format on the admin console, not highlighted
in this chapter.
Some of the kit features actively managed by the board controller are:
•
•
•
•
•
The on-board debugger, which can flash and debug both on-board and external targets.
The Advanced Energy Monitor, which provides real-time energy profiling of the user application.
The Packet Trace Interface, which is used in conjunction with PC software to provide detailed insight into an active radio network.
The Virtual COM Port and interfaces, which provide ways to transfer application data between the host PC and the target processor.
The admin console, which provides configuration of the various board features.
Silicon Labs publishes updates to the board controller firmware in the form of firmware upgrade packages. These updates may enable
new features or fix issues. See Section for details on firmware upgrade.
7.2 Admin Console
The admin console is a command line interface to the board controller on the kit. It provides functionality for configuring the kit behavior
and retrieving configuration and operational parameters.
7.2.1 Connecting
The Wireless STK must be connected to Ethernet using the Ethernet connector in the top left corner of the mainboard for the admin
console to be available. See Section 9.1.2 Ethernet Interface for details on the Ethernet connectivity.
Connect to the admin console by opening a telnet connection to the kit's IP address, port number 4902.
When successfully connected, a WSTK> prompt is displayed.
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UG531: BRD4191A BG22 Direction Finding Radio Board User's Guide
Board Controller
7.2.2 Built-in Help
The admin console has a built-in help system which is accessed by the help command. The help command will print a list of all top
level commands:
WPK> help
*************** Root commands ****************
aem
AEM Configuration and Information Commands
[ avg, calibrate, calinfo ]
boardid
Commands for board ID probe.
[ list, probe ]
dbg
Debug interface status and control
[ info, mode ]
dch
Datachannel control and info commands
[ info, message ]
discovery
Discovery service commands.
[ key ]
net
Network commands.
[ dnslookup, ip, mac ]
pti
Packet trace interface status and control
[ config, disable, dump, ... ]
quit
Exit from shell
serial
Serial channel commands
[ vcom ]
sys
System commands
[ crashlog, nickname, reset, ... ]
target
Target commands.
[ button, go, halt, ... ]
time
Time Sync Service commands
[ client, disable, info, ... ]
user
User management functions
[ login,]
The help command can be used in conjunction with any top level command to get a list of sub-commands with descriptions. For example, pti help will print a list of all available sub-commands of pti:
WPK> pti help
*************** pti commands ****************
config
Configure packet trace
disable
Disable packet trace
dump
Dump PTI packets to the console as they come
enable
Enable packet trace
info
Packet trace state information
This means that running pti enable will enable packet trace.
7.2.3 Command Examples
PTI Configuration
pti config 0 efruart 1600000
Configures PTI to use the "EFRUART" mode at 1.6 Mb/s.
Serial Port Configuration
serial config vcom handshake enable
Enables hardware handshake on the VCOM UART connection.
7.3 Virtual UART
The Virtual UART (VUART) interface provides a high-performance application data interface that does not require additional I/O pins
apart from the debug interface.
The Wireless STK makes the VUART interface available on TCP/IP port 4900.
7.3.1 Target to Host
Target to host communication utilizes the SWO-pin of the debug interface through the ITM debug peripheral. This approach allows a
sleepy target device to enter all energy modes and still wake up intermittently to send debug information. The baud rate of the SWO
data is locked to 875 kHz.
VUART utilizes ITM stimulus port 0 for general purpose printing. Silicon Labs' networking stacks utilize ITM stimulus port 8 for debug
printing. The data on port 8 is encapsulated in additional framing and will also appear in the Simplicity Studio Network Analyzer.
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UG531: BRD4191A BG22 Direction Finding Radio Board User's Guide
Board Controller
7.3.2 Host to Target
Host to target communication utilizes SEGGER's Real Time Transfer (RTT) technology. A full explanation of how this works can be
found in J-Link/J-Trace User Guide (UM08001). Briefly summarized, RTT consists of a structure called the RTT Control Block, which is
located in RAM. This control block points to circular buffers that the debugger can write data into. The target application can then read
data out of this circular buffer.
The board controller will start searching for the RTT Control Block upon receiving data on TCP/IP port 4900. If the board controller is
unable to locate the RTT Control Block, it will return an error message on the same connection. For the board controller to be able to
locate the RTT Control Block, it has to be aligned on a 1024-byte boundary in RAM.
After initializing the RTT connection, the target will only enter emulated EM2 and EM3 where the power consumption remains similar to
EM1. This is because RTT utilizes the debug interface which requires use of high-frequency oscillators. Energy modes EM4S and
EM4H will work as normal. When debugging energy consumption, it is therefore important to not send data on TCP/IP port 4900 as not
to instantiate the RTT connection.
7.3.3 Limitations
• Because the SWO-connection can be disabled by the debugger at will, it is important for the target application to verify that SWO is
enabled and configured before each transmission on the interface.
• After initializing host to target communication over RTT by sending data on TCP/IP port 4900, the target application will be unable to
enter EM2 and EM3. This is because RTT utilizes the debug connection of the target.
• VUART might not work reliably during an active debugging session. This is because there is contention over the target's debug interface. The board controller will defer accessing the target until it is made available by the host debugger.
• VUART is designed with the assumption that only the board controller will access the RTT control block. If the target application
uses RTT for other purposes, such as Segger SystemView, refrain from using VUART.
7.3.4 Troubleshooting
Problem
Solution
No data received after ending a
debug session.
After certain debugger operations, the host computer manually disables SWO on the target in order
to conserve power. This might cause SWO data to not appear if the target application initialized
SWO before the debugger has disconnected. Either press the RESET-button on the Wireless Starter Kit to reset the target application or make sure that the target application verifies that SWO is enabled and configured before sending any data.
No data received after flashing
a new application.
Other issues
Disconnect from TCP port 4900, press the RESET-button on the kit, then reconnect to 4900. If this
does not fix the issue, try to restart the kit by unplugging and replugging the USB cable.
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UG531: BRD4191A BG22 Direction Finding Radio Board User's Guide
Advanced Energy Monitor
8. Advanced Energy Monitor
8.1 Introduction
Any embedded developer seeking to make their embedded code spend as little energy as the underlying architecture supports needs
tools to easily and quickly discover inefficiencies in the running application. This is what the Simplicity Energy Profiler is designed to do.
In real-time, the Energy Profiler will graph and log current as a function of time while correlating this to the actual target application code
running on the EFR32BG22. There are multiple features in the profiler software that allow for easy analysis, such as markers and statistics on selected regions of the current graph or aggregate energy usage by different parts of the application. The Energy Profiler is
available through Simplicity Studio.
8.2 Code Correlation
By using the Energy Profiler, current consumption and voltage can be measured and linked to the actual code running on the
EFR32BG22 in realtime. The Energy Profiler gets its data from the board controller on the mainboard through the Advanced Energy
Monitor (AEM). The current signal is combined with the target processor's Program Counter (PC) sampling by utilizing a feature of the
ARM CoreSight debug architecture, and the Instrumentation Trace Macrocell (ITM) block can be programmed to sample the MCU's PC
at periodic intervals and output these over SWO pin ARM devices. When these two data streams are fused and correlated with the
running application's memory map, an accurate statistical profile can be built that shows the energy profile of the running application in
real-time.
8.3 AEM Circuit
The AEM circuit on the Wireless Pro Kit Mainboard (BRD4002A) and the Wireless STK Mainboard (BRD4001A) measures the current
through a sense resistor inside the feedback loop of a low-dropout regulator (LDO). The output voltage of this LDO powers the
EFR32BG22 when the power slide switch is in the AEM position. AEM usage on both mainboards is similar, but the implementation and
perfomance on the Wireless Pro Kit Mainboard (BRD4002A) has some key differences including the utilization of two sense resistors
instead of one and a different LDO, which is explained in Section 8.3.1 AEM Details. The AEM implementation on the Wireless Pro Kit
Mainboard (BRD4002A) is shown in the figure below.
5V
Power Select
Switch
LDO
0.5 Ω
10 Ω
Sense Resistors
VMCU
High Calibrate
Range
Current Sense
Amplifier
EFR32
Peripherals
G0
AEM
Processing
Multiple Gain
Stages
G1
Figure 8.1. Advanced Energy Monitor On The Wireless Pro Kit Mainboard (BRD4002A)
Note: The VMCU regulator feedback point is after the sense resistor to ensure that the VMCU voltage is kept constant when the output
current changes. Series resistances in the current path will, however, cause some IR drop on VMCU.
Note: The AEM circuit only works when the kit is powered and the power switch is in the AEM position.
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UG531: BRD4191A BG22 Direction Finding Radio Board User's Guide
Advanced Energy Monitor
8.3.1 AEM Details
The main differences between the AEM on the Wireless Pro Kit Mainboard (BRD4002A) and the Wireless STK Mainboard (BRD4001A)
is summarized in the table below with more in-depth information given in the text to follow.
Table 8.1. Advanced Energy Monitor Parameters
Parameter
BRD4002A
BRD4001A
Voltage
1.8 - 3.6 V
3.3 V
100 kHz
10 kHz
10.5 Ω / 0.5 Ω
2.35 Ω
0 - 495 mA
0 - 95 mA
Sample Rate
Sense Resistor
Measurement Range1
Note:
1. The current sourcing capabilities of the LDO may be different than the measurement range.
Wireless Pro Kit Mainboard (BRD4002A) AEM Design Details
The AEM circuitry on the Wireless Pro Kit Mainboard is capable of measuring current signals in the range of approximately 0.1 µA to
495 mA. This is accomplished through a combination of a highly capable current sense amplifier, multiple sense resistors and gain
stages, and signal processing within the kit's board controller before the current sense signal is read by a host computer with 100 kHz
sample rate for display and/or storage. Averaging on the output data may be required to achieve sufficient accuracy in some situations,
such as low currents, which can be traded for lower bandwidth. High current applications require that the regulator is able to supply
enough current as described in Section 5.2 Kit Power.
At low currents the current sense amplifier measures the voltage drop over a 10.5 Ω resistive path. The gain stage further amplifies this
voltage with two different parallel gain settings to obtain two current ranges. The transition between these two ranges occurs around
150 µA. When the current exceeds a threshold, which is typically between 10 and 30 mA, the AEM circuitry switches from the 10.5 Ω
resistive path to a 0.5 Ω sense resistor and is now capable of measuring currents up to approximately 495 mA. Should the current drop
below the threshold again, the sense resistor is changed back to the 10.5 Ω resistive path and the AEM is back to using two different
gain stages depending on whether the current is above or below 150 µA.
The expected typical accuracy of the AEM on the Wireless Pro Kit Mainboard is within 1 %, except for currents in the low tens of microamps where offset errors start to dominate. In this low current region, the expected typical accuracy is some hundred nanoamps. At kit
power-up or on a power-cycle, an automatic AEM calibration is performed which compensates for offset errors in the current sense
amplifiers. To achieve the stated accuracy, averaging of the AEM output data is required in certain situations (typically at low currents
and close to the bottom of the measurement ranges) to reduce noise. Averaging can be applied in Energy Profiler to suit different requirements during or after the acquisition. The analog bandwidth of the measurement circuit depends on multiple factors, such as output current and capacitance on the VMCU net, and may be lower than the output data rate. Generally, higher output current and lower
capacitance on VMCU gives a higher analog bandwidth.
Wireless STK Mainboard (BRD4001A) AEM Design Details
The AEM circuitry on the Wireless STK Mainboard works conceptually in a similar way to the implementation on the Wireless Pro Kit
Mainboard except for two key differences: it uses only one 2.35 Ω sense resistor and the low-dropout regulator (LDO) is different. For
details about the two implementations, the reader is encouraged to see the schematics.
The AEM on the Wireless STK Mainboard is capable of measuring currents in the range of 0.1 µA to 95 mA. The second stage amplifier
amplifies the signal with two different gain settings with the transition occurring around 250 µA. For currents above 250 µA, the AEM is
accurate within 0.1 mA. When measuring currents below 250 µA, the accuracy increases to 1 µA. Even though the absolute accuracy is
1 µA in the sub 250 µA range, the AEM can detect changes in the current consumption as small as 0.1 µA. It is possible to source
currents above the measurement range as decribed in Section 5.2 Kit Power. The board controller outputs the AEM data with 10 kHz
sample rate.
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UG531: BRD4191A BG22 Direction Finding Radio Board User's Guide
On-Board Debugger
9. On-Board Debugger
The Wireless Pro Kit Mainboard and the Wireless STK Mainboard contain an integrated debugger, which can be used to download
code and debug the EFR32BG22. In addition to programming a target on a plug-in radio board, the debugger can also be used to program and debug external Silicon Labs EFM32, EFM8, EZR32, and EFR32 devices connected through the debug connector.
The debugger supports three different debug interfaces for Silicon Labs devices:
• Serial Wire Debug is supported by all EFM32, EFR32, and EZR32 devices
• JTAG is supported by EFR32 and some EFM32 devices
• C2 Debug is supported by EFM8 devices
For debugging to work properly, make sure the selected debug interface is supported by the target device. The debug connector on the
board supports all three of these modes.
9.1 Host Interfaces
The Wireless STK supports connecting to the on-board debugger using either Ethernet or USB.
Many tools support connecting to a debugger using either USB or Ethernet. When connected over USB, the kit is identified by its J-Link
serial number. When connected over Ethernet, the kit is normally identified by its IP address. Some tools also support using the serial
number when connecting over Ethernet; however, this typically requires the computer and the kit to be on the same subnet for the discovery protocol (using UDP broadcast packets) to work.
9.1.1 USB Interface
The USB interface is available whenever the USB connector on the left-hand side of the mainboard is connected to a computer.
9.1.2 Ethernet Interface
The Ethernet interface is available when the mainboard Ethernet connector in the top left corner is connected to a network. Normally,
the kit will receive an IP address from a local DHCP server, and the IP address is printed on the LCD display. If your network does not
have a DHCP server, you need to connect to the kit via USB and set the IP address manually using Simplicity Studio, Simplicity
Commander, or J-Link Configurator.
For the Ethernet connectivity to work, the kit must still be powered through the USB Mini-B connector. See Section 5.2.1 Board Controller Power for details.
9.1.3 Serial Number Identification
All Silicon Labs kits have a unique J-Link serial number which identifies the kit to PC applications. This number is 9 digits and is normally on the form 44xxxxxxx.
The J-Link serial number is normally printed at the bottom of the kit LCD display.
9.2 Debug Mode
The on-board debugger can be used to debug the EFR32BG22 on the BG22 Direction Finding Radio Board through the debug connector and a BRD8010B STK/WSTK Debug Adapter. To use this mode, set the debug mode to [Out].
Host
Computer
USB
Board
Controller
DEBUG HEADER
STK/WSTK
Debug Adapter
(BRD8010B)
RADIO BOARD
Figure 9.1. Debug OUT
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UG531: BRD4191A BG22 Direction Finding Radio Board User's Guide
On-Board Debugger
9.3 Debugging During Battery Operation
When the EFR32BG22 is battery-powered and the J-Link USB is still connected, the on-board debug functionality is available. If the
USB power is disconnected, the Debug IN mode will stop working.
If debug access is required when the target is running off another energy source, such as a battery, and the board controller is powered
down, make direct connections to the GPIOs used for debugging, which are exposed on the breakout pads.
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UG531: BRD4191A BG22 Direction Finding Radio Board User's Guide
Radio
10. Radio
10.1 RF Section
This section gives a short introduction to the RF section of the board.
The schematic of the RF section is shown in the figure below.
9
3
2
4
L1
RF I / O
RF2G4_IO
50R_C1
14
10
12
2
BLM18AG102SN1
C205
C204
100N
120P
PAVDD
L203
1
CC1
50R_CC1
C1
15
2
BLM18AG102SN1
GND
C207
C206
100N
120P
50R_R1
C2
C3
R1
50R_EFR32_RF_OUT
0R
HFXTAL_O
P202
GND
L202
1
RF Cr ys t a l
HFXTAL_I
X1
38.4 MHz
1
VDCDC
2. 4 GHz ma t c hi ng
ne t wor k
U1B
EFR32BG22C224F512IM40
Hi gh Fr e que nc y Cr ys t a l
RF Ana l og Powe r
RFVDD
GND
Gr ound
RFVSS
GND
GND
13
R2
0R
NM
PA Powe r
50R_P2
3
1
2
U.FL
GND
PAVDD
GND
GND
Figure 10.1. Schematic of the RF Section
10.1.1 Description of the RF Matching
The impedance of the RF port of the EFR32BG22 is matched to 50 Ohm: the RF2G4_IO pin is connected to a three-element impedance matching and harmonic filter circuitry, and a dc blocking capacitor. The output of the matching circuit is connected to the Direction Finding Antenna Array.
10.1.2 RF Section Power Supply
On the BRD4191A, the supply for the radio (RFVDD) and the power amplifier (PAVDD) is connected to the on-chip DC-DC converter.
By default, the DC-DC converter provides 1.8 V for the entire RF section (for details, see the BRD4191A schematic).
10.1.3 RF Matching Bill of Materials
The BRD4191A RF matching network bill of materials is shown in the following table.
Table 10.1. BRD4191A RF Matching Network Bill of Materials
Component name
Value
Manufacturer
Part Number
L1
2.6 nH
Murata
LQP03HQ2N6B02
C1
1.2 pF
Murata
GRM0335C1H1R2BA01D
C2
1.3 pF
Murata
GRM0335C1H1R3BA01D
C3
Not Mounted
-
-
CC1
18 pF
Murata
GJM0335C1E180GB01D
10.1.4 Antenna
The BRD4191A has 16 patch antennas optimized for direction finding applications.
For detailed description of the antennas, design guidelines, antenna switching concept, refer to AN1195: Antenna Array Design Guidelines for Direction Finding.
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UG531: BRD4191A BG22 Direction Finding Radio Board User's Guide
Radio
10.3 Conducted Power Measurements
During measurements, the BRD4191A BG22 Direction Finding Radio Board was attached to a Wireless Pro Kit Mainboard (BRD4002A)
which was supplied by USB. The voltage supply for the radio board (VMCU) was 3.3 V and for the power amlifier (PAVDD), it was
1.8 V.
10.3.1 Conducted Power Measurements with Unmodulated Carrier
The transceiver was operated in unmodulated carrier transmission mode. The output power of the radio was set to 6 dBm. The typical
output spectrum is shown in the following figure.
Figure 10.2. Typical Output Spectrum of the BRD4191A; PAVDD = 1.8 V
As it is shown in the figure, the fundamental is a bit below 6 dBm, the harmonics are under their corresponding limits.
Note: The conducted measurement is performed by connecting the on-board UFL connector to a spectrum analyzer through an SMA
conversion adapter (P/N: HRMJ-U.FLP(40)). This connection itself introduces approximately 0.3 dB insertion loss.
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UG531: BRD4191A BG22 Direction Finding Radio Board User's Guide
Radio
10.3.2 Relaxation with Modulated Carrier
Depending on the applied modulation scheme and the Spectrum Analyzer settings specified by the relevant EMC regulations, the
measured power levels are usually lower compared to the results with unmodulated carrier. These differences have been measured
and used as relaxation factors on the results of the radiated measurement performed with unmodulated carrier. This way, the radiated
compliance with modulated transmission can be evaluated.
In this case, both the ETSI EN 300-328 and the FCC 15.247 regulations define the following Spectrum Analyzer settings for measuring
the unwanted emissions above 1 GHz:
• Detector: Average
• RBW: 1 MHz
The table below shows the relative levels of the measured modulated signals compared to the unmodulated levels with the above
Spectrum Analyzer settings in case of the supported modulation schemes.
Table 10.2. Measured Relaxation Factors for the Supported Modulation Schemes
Applied Modulation
(Packet Length:
255 bytes)
BLE Coded PHY:
125 Kb/s (PRBS9) [dB]
BLE Coded PHY:
500 Kb/s (PRBS9) [dB]
BLE 1M PHY: 1 Mb/s
(PRBS9) [dB]
BLE 2M PHY: 2 Mb/s
(PRBS9) [dB]
2nd harmonic
-2.7
-3.1
-3.3
-9.1
3rd harmonic
-4.8
-5.2
-5.2
-10.7
4th harmonic
-5.5
-6.5
-6.7
-11.9
5th harmonic
-6.3
-6.5
-6.7
-11.4
As it can be observed, the BLE 125 Kb/s coded modulation scheme has the lowest relaxation factors. These values will be used as the
worst case relaxation factors for the radiated measurements.
10.4 Radiated Power Measurements
The output power of the EFR32BG22 was set to 6 dBm. The board was supplied through its USB connector by connecting to a PC
through a USB cable.
During the measurements, the board was rotated in three cuts. See the reference plane illustration in the figure below. The radiated
powers of the fundamental and the harmonics were measured with horizontal and vertical reference antenna polarizations.
X
Z
Y
Figure 10.3. DUT Reference Planes
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UG531: BRD4191A BG22 Direction Finding Radio Board User's Guide
Radio
10.4.1 Maximum Radiated Power Measurement
The transceiver was operated in unmodulated carrier transmission mode and the output power of the radio was set to 6 dBm. Antenna
#2 was used as the transmitter antenna. The results are shown in the table below.
The correction factors are applied based on the BLE 125 Kb/s coded modulation, shown in section 10.3.2 Relaxation with Modulated
Carrier. For the rest of the supported modulation schemes the correction factors are larger, thus the related calculated margins would
be higher compared to the ones shown in the table below. Thus, the below margins can be considered as worst case margins.
Table 10.3. Maximums of the Measured Radiated Powers of BRD4191A
BLE 125 Kb/s Coded Modulation
Frequency
(2440 MHz)
Measured Unmodulated EIRP
[dBm]
Orientation
Correction Factor [dB]
Calculated
Modulated EIRP
[dBm]
Modulated Margin [dB]
Fund
-5.6
XZ/H
NA (0 is used)
-5.6
35.6
30.0
2nd
-60.2
YZ/H
-2.7
-62.9
21.7
-41.2
3rd
-38.7
XZ/H
-4.8
-43.5
2.3
-41.2
4th
20
-30.0
5th
-47.7
XZ/H
-6.3
-54.0
12.8
-41.2
Limit in EIRP
[dBm]
* Signal level is below the Spectrum Analyzer noise floor
As it is shown in the table, the radiated power of the fundamental is low. This is due to the long transmission lines, the low antenn gain
and the insertion loss of the switches on the board. In total, those introduce ~10dB loss.
The 3rd harmonic is above the limit with unmodulated transmission, but with the applied correction factor its level is compliant. The rest
of the harmonics are under their corresponding limits with large margins.
10.5.1 Recommendations for 2.4 GHz ETSI EN 300-328 Compliance
As it was shown in the previous chapter, with the EFR32BG22 output power set to 6 dBm, the radiated power of the fundamental of the
BRD4191A complies with the 20 dBm limit of the ETSI EN 300-328. With the supported modulation schemes, the harmonics are also
compliant with the relevant limits. Although the BRD4191A Radio Board has an option for mounting a shielding can, it is not required for
the compliance.
10.5.2 Recommendations for 2.4 GHz FCC 15.247 Compliance
As it was shown in the previous chapter, with the EFR32BG22 output power set to 6 dBm, the radiated power of the fundamental of the
BRD4191A complies with the 30 dBm limit of the FCC 15.247. With the supported modulation schemes, the harmonics are also compliant with the relevant limits. Although the BRD4191A Radio Board has an option for mounting a shielding can, it is not required for the
compliance.
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UG531: BRD4191A BG22 Direction Finding Radio Board User's Guide
Kit Configuration and Upgrades
11. Kit Configuration and Upgrades
The kit configuration dialog in Simplicity Studio allows you to change the J-Link adapter debug mode, upgrade its firmware, and change
other configuration settings. To download Simplicity Studio, go to silabs.com/simplicity.
In the main window of the Simplicity Studio's Launcher perspective, the debug mode and firmware version of the selected J-Link adapter are shown. Click the [Change] link next to any of these settings to open the kit configuration dialog.
Figure 11.1. Simplicity Studio Kit Information
Figure 11.2. Kit Configuration Dialog
11.1 Firmware Upgrades
You can upgrade the kit firmware through Simplicity Studio. Simplicity Studio will automatically check for new updates on startup.
You can also use the kit configuration dialog for manual upgrades. Click the [Browse] button in the [Update Adapter] section to select
the correct file ending in .emz. Then, click the [Install Package] button.
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UG531: BRD4191A BG22 Direction Finding Radio Board User's Guide
Schematics, Assembly Drawings, and BOM
12. Schematics, Assembly Drawings, and BOM
Schematics, assembly drawings, and bill of materials (BOM) are available through Simplicity Studio when the kit documentation package has been installed. They are also available from the kit page on the Silicon Labs website: silabs.com.
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UG531: BRD4191A BG22 Direction Finding Radio Board User's Guide
Kit Revision History and Errata
13. Kit Revision History and Errata
13.1 Revision History
The kit revision can be found printed on the box label of the kit, as outlined in the figure below. The kit revision history is summarized in
the table below.
BG22 Direction Finding Radio Board
BG22-RB4191A
10-06-22
2220000960
A02
Figure 13.1. Revision Info
Table 13.1. Kit Revision History
Kit Revision
Released
Description
A00
25 January 2022
New kit introduction of BG22-RB4191A.
13.2 Errata
There are no known errata at present.
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UG531: BRD4191A BG22 Direction Finding Radio Board User's Guide
Board Revision History and Errata
14. Board Revision History and Errata
14.1 Revision History
The board revision can be found laser printed on the board, and the board revision history is summarized in the following table.
Table 14.1. Board Revision History
Revision
Released
Description
A03
3 May 2022
Updated PCB revision.
A02
25 January 2022
Updated PCB variant to final. Added optional parallel antenna tuning components.
A01
13 January 2022
Updated PCB variant. No change in the components.
A00
6 August 2021
Initial production release.
14.2 Errata
There are no known errata at present.
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UG531: BRD4191A BG22 Direction Finding Radio Board User's Guide
Document Revision History
15. Document Revision History
Revision 1.0
June 2022
• Initial document release.
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Disclaimer
Silicon Labs intends to provide customers with the latest, accurate, and in-depth documentation of all peripherals and modules available for system and software implementers using or intending to use the Silicon Labs products. Characterization data, available modules and peripherals, memory sizes and memory addresses refer to each
specific device, and “Typical” parameters provided can and do vary in different applications. Application examples described herein are for illustrative purposes only. Silicon
Labs reserves the right to make changes without further notice to the product information, specifications, and descriptions herein, and does not give warranties as to the
accuracy or completeness of the included information. Without prior notification, Silicon Labs may update product firmware during the manufacturing process for security or
reliability reasons. Such changes will not alter the specifications or the performance of the product. Silicon Labs shall have no liability for the consequences of use of the information supplied in this document. This document does not imply or expressly grant any license to design or fabricate any integrated circuits. The products are not designed or
authorized to be used within any FDA Class III devices, applications for which FDA premarket approval is required or Life Support Systems without the specific written consent
of Silicon Labs. A “Life Support System” is any product or system intended to support or sustain life and/or health, which, if it fails, can be reasonably expected to result in
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