Nordic Semiconductor nRF52 DK User manual

nRF52 DK Hardware
v2.x.x
User Guide
4397_500 / 2022-10-19

Contents
Revision history.................................. iii
1Introduction................................... 4
2Kit content.................................... 5
3Interface MCU.................................. 6
3.1 IF Boot/Reset button ............................... 6
3.2 Virtual COM port ................................ 6
3.2.1 Dynamic HWFC handling ............................7
3.3 Interface MCU firmware ..............................7
3.4 MSD ...................................... 8
4Hardware description.............................. 9
4.1 Hardware drawings ................................ 9
4.2 Block diagram ................................. 10
4.3 Power supply ..................................10
4.4 Connector interface ............................... 12
4.5 Buttons and LEDs ................................ 14
4.5.1 I/O expander for buttons and LEDs ....................... 15
4.6 32.768 kHz crystal ................................17
4.7 Debug input .................................. 18
4.8 Debug output ................................. 18
4.9 Connectors for programming external boards .................... 19
4.10 NFC antenna interface ............................. 20
4.11 Solder bridge and test point overview ....................... 22
5Measuring current............................... 25
5.1 Preparing the DK ................................ 25
5.2 Using an oscilloscope for current profile measurement ................ 26
5.3 Using an ampere meter for current measurement .................. 27
6RF measurements............................... 29
Glossary ..................................... 30
Recommended reading.............................. 32
Legal notices................................... 33
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Revision history
Date Description
2022-10-19 • Updated content for nRF52 DK v2.2.0
• Editorial changes
• Removed:
• Setting up the development kit
• Software tools
• Start developing
April 2020 Editorial changes
December 2018 Updated:
•Introduction on page 4
• Software tools
•Measuring current on page 25
•Preparing the DK on page 25
•NFC antenna interface
February 2017 • Created PDF for nRF52 DK v1.1.x (valid for all DK versions)
• Added MSD on page 8
• Updated:
•Interface MCU firmware on page 7
•Solder bridge and test point overview on page 22
Previous versions
PDF files for relevant previous versions are available here:
•nRF52 DK User Guide v1.3.1
4397_500 iii

1Introduction
The nRF52 Development Kit (DK) is a hardware development platform used to design and develop
application firmware on the nRF52832, nRF52810, or nRF52805 System on Chip (SoC)s.
To set up the nRF52 DK, see Getting started with the nRF52 DK. To start developing your application, see
the Software development Getting Started Guides. For more detailed documentation regarding nRF52810
development, see Developing for nRF52810 in the SDK documentation.
Key features
• nRF52832 flash-based Bluetooth® Low Energy and ANT™/ANT+™ SoC solution
• Buttons and LEDs for user interaction
• I/O interface for Arduino form factor plug-in modules
• SEGGER J-Link OB Debugger with debug out functionality
• UART interface through virtual COM port
• Drag-and-drop Mass Storage Device (MSD) programming
• Support for NFC-A Listen Mode
• Mbed™ enabled
For access to firmware source code, hardware schematics, and layout files, see www.nordicsemi.com.
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2Kit content
The nRF52 DK includes hardware, preprogrammed firmware, documentation, hardware schematics, and
layout files.
The nRF52 DK (PCA10040) comes with a Near Field Communication (NFC) antenna.
Figure 1: nRF52 DK (PCA10040) and NFC antenna
Hardware files
The hardware design files including schematics, Printed Circuit Board (PCB) layout files, bill of materials,
and Gerber files for the nRF52 DK are available on the nRF52832 product page.
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3Interface MCU
The interface MCU on the nRF52 DK runs SEGGER J-Link OB or Mbed OB interface firmware and is used to
program and debug the firmware of the nRF52832 SoC.
Figure 2: Interface MCU
3.1 IF Boot/Reset button
The nRF52 DK has an IF Boot/Reset button (SW5).
This button is connected to the interface MCU on the DK and has two functions:
• Resetting the nRF52832 SoC
• Entering the bootloader mode of the interface MCU
During normal operation the button functions as a reset button for the nRF52832 SoC. For this to work,
pin reset on P0.21 needs to be enabled in embedded firmware.
The button is also used to enter the bootloader mode of the interface MCU. To enter the bootloader
mode, keep the reset button pressed while powering up the DK until LD5 starts to blink. You can power up
the DK either by disconnecting and reconnecting the USB cable or by toggling the power switch (SW6).
3.2 Virtual COM port
The onboard interface MCU features a Universal Asynchronous Receiver/Transmitter (UART) interface
through a virtual COM port.
The virtual COM port has the following features:
• Flexible baud rate setting up to 1 Mbps (baud rate 921 600 is not supported)
• Dynamic Hardware Flow Control (HWFC) handling
• Tri-stated UART lines when no terminal is connected
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Interface MCU
The following table shows an overview of the UART connections on the nRF52832 SoC and the interface
MCU.
GPIO nRF52832 nRF52832 UART Interface MCU UART
P0.05 RTS CTS
P0.06 TXD RXD
P0.07 CTS RTS
P0.08 RXD TXD
Table 1: Relationship of UART connections on nRF52832 and interface MCU
The UART signals are routed directly to the interface MCU. The UART pins connected to the interface MCU
are tri-stated when no terminal is connected to the virtual COM port on the computer.
Note: The terminal software used must send a Data Terminal Ready (DTR) signal to configure the
UART interface MCU pins.
P0.05 (Request to Send (RTS)) and P0.07 (Clear to Send (CTS)) can be used freely when HWFC is disabled
on the SoC.
Note: The Mbed OB interface does not support HWFC through the virtual COM port.
3.2.1 Dynamic HWFC handling
When the interface MCU receives a DTR signal from a terminal, it performs automatic HWFC detection.
Automatic HWFC detection is done by driving P0.07 (CTS) from the interface MCU and evaluating the state
of P0.05 (RTS) when the first data is sent or received. If the state of P0.05 (RTS) is high, HWFC is assumed
not to be used. If HWFC is not detected, both CTS and RTS can be used freely by the nRF application.
After a power-on reset of the interface MCU, all UART lines are tri-stated when no terminal is connected
to the virtual COM port. Due to the dynamic HWFC handling, if HWFC has been used and detected, P0.07
(CTS) is driven by the interface MCU until a power-on reset has been performed or until a new DTR signal
is received and the detection is redone.
To ensure that the UART lines are not affected by the interface MCU, the solder bridges for these signals
can be cut and later resoldered if needed. This might be necessary if UART without HWFC is needed while
P0.05 (RTS) and P0.07 (CTS) are used for other purposes.
3.3 Interface MCU firmware
The onboard interface MCU is factory programmed with an Mbed-compliant bootloader. This feature
makes it possible to swap interface firmware between the factory preloaded SEGGER J-Link OB and the
Mbed interface firmware.
See IF Boot/Reset button on page 6 for instructions on how to enter the bootloader mode.
To swap interface MCU firmware, drag the Interface image (.bin) into the mounted bootloader drive on
the connected computer and power cycle the DK.
Both the Mbed interface firmware and the J-Link OB image can be downloaded from
www.nordicsemi.com.
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Interface MCU
Note: When in bootloader mode, do not drag and drop any files except those downloaded from
www.nordicsemi.com for use with the interface MCU. If a wrong file is used, it can overwrite the
bootloader and ruin the interface MCU firmware without the possibility of recovery.
3.4 MSD
The interface MCU features an MSD. This makes the DK appear as an external drive on your computer.
This drive can be used for drag-and-drop programming. However, files cannot be stored on this drive. By
copying a HEX file to the drive, the interface MCU programs the file to the device.
Note:
• Windows might try to defragment the MSD part of the interface MCU. If this happens, the
interface MCU disconnects and becomes unresponsive. To return to normal operation, the DK
must be power cycled.
• Your antivirus software might try to scan the MSD part of the interface MCU. Some antivirus
programs trigger a false positive alert in one of the files and quarantine the unit. If this happens,
the interface MCU becomes unresponsive.
• If the computer is set up to boot from USB, it can try to boot from the DK if the DK is connected
during boot. This can be avoided by unplugging the DK before a computer restart, or changing
the boot sequence of the computer.
You can also disable the MSD of the DK by using the msddisable command in J-Link Commander. To
enable, use the msdenable command. These commands take effect after a power cycle of the DK and
stay this way until changed again.
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4Hardware description
The nRF52 DK (PCA10040) features an onboard programming and debugging solution.
In addition to radio communication, the SoC can communicate with a computer through Universal Serial
Bus (USB) and a virtual COM port provided by the interface MCU.
4.1 Hardware drawings
nRF52 DK hardware drawings show both sides of the PCA10040.
Figure 3: nRF52 DK (PCA10040) front view
Figure 4: nRF52 DK (PCA10040) back view
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Hardware description
4.2 Block diagram
The block diagram illustrates the nRF52 DK functional architecture.
External supply Current
measurement
USB
Battery
Buttons
Voltage regulator
LEDs
GPIO
nRF52832
PCB
Antenna
Interface MCU
VBUS USB sense
Data
Osc
32.768 kHz
IF Boot/Reset
UART
SWD
VCC_nRF
Osc
32 MHz
Debug inDebug out
Power switch
Power switch Matching
network
NFC
antenna
SWF switch/
RF connector
I/O
expander
Debouncing
filter Switch
Switch
Figure 5: Block diagram
4.3 Power supply
The nRF52 DK has three power options: USB (5 V), external power supply (1.7–3.6 V), and coin cell battery.
Figure 6: Power supply options (front)
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Hardware description
Figure 7: Power supply options (back)
The 5 V from the USB is regulated down to 3.3 V through an onboard voltage regulator. The battery and
external power supply are not regulated. The power from the regulator and external supply is routed
through diodes for reverse voltage protection (D1 and D7), where the circuit is supplied from the source
with the highest voltage. The power from the battery is routed through a load switch and a transistor.
These are controlled by the regulator voltage or external voltage, so if any of the two other sources are
present, the battery is disconnected from the circuit.
Note: When USB is not powered, the interface MCU is in dormant state and draws an additional
current of ~ 20 μA to maintain the reset button functionality. This affects current consumption, but
not the nRF52832 current measurements, as described in Measuring current on page 25.
C18
100nF
C17
1.0µF
C16
1.0
µ
F
Vin
GND
Vout
U3
AP7333-33SAG-7
VDD
R6
N.C.
SB9
VDD_nRFVBUS
SB10
SB11
TP14
VBUS'
V5V
TP12
TP13
1
2
P21
Pin List 1x2, Angled
1
2
P22
Pin List 1x2, Angled
+
Bat1
Bat Holder CR2032
VREG_IN
VBUS'
VIO
SB35
VREG_OUT
VIN
A2
VOUT
A1
CTRL B2
GND
B1
U11
TCK106AG
R48
1M0
VSUPPLY
VSUPPLY
R47
1M0
VSUPPLY
VEXT_DETECT
R46
1M0
VSUPPLY
SB34
SB33
R60
1M0
R44
33k
R45
47k
VBUS'
VREG_DETECT
VEXT_DETECT
USB_DETECT
C56
100nF
VSUPPLY
VSUPPLY
VEXT_DETECT
VBAT
C57
100nF
VSUPPLY
SB12
R49
100k
Q4A
TSM250N02DCQ RFG
Q4B
TSM250N02DCQ RFG
Q5A
TSM2537CQ RFG
Q5B
TSM2537CQ RFG
Q3A
TSM2537CQ RFG
Q3B
TSM2537CQ RFG
R50
220k
R51
220k
D7
NSR0620P2T5G
D1
NSR0620P2T5G
Not mounted
D8
NSR0620P2T5G
SW6
Switch
GND
VCC
U12
NC7SV11L6X
GND
VCC
U13
NC7SV11L6X
VREG_DETECT
VREG_DETECT
Figure 8: Power supply circuitry
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Hardware description
The reverse voltage protection diodes for the regulator and external supply add a voltage drop to the
supply voltage of the circuit. To avoid this voltage drop, the diodes can be bypassed by shorting one or
more solder bridges.
Power source Protection bypass Voltage level
USB SB10 3.3 V
External supply SB12 1.7 V - 3.6 V
Table 2: Protection diode bypass solder bridges
Figure 9: Protection diode bypass solder bridges
Note: Connect only one power source at the time. Shorting the solder bridges removes the reverse
voltage protection.
4.4 Connector interface
Access to the nRF52832 General-Purpose Input/Output (GPIO)s is available from connectors P2, P3, P4, P5,
and P6.
The P1 connector provides access to ground and power on the nRF52 DK.
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Hardware description
Figure 10: nRF52 DK connectors
Some of the signals are also available on connectors P7, P8, P9, P10, P11, and P12, located on the back
side of the DK. By mounting pin lists on the connector footprints, the nRF52 DK can be used as a shield for
3.3 V Arduino motherboards or other boards that follow the Arduino standard.
For easy access to GPIO, power, and ground, the signals can also be found on the through-hole connectors
P13–P17.
Note:
Some pins have default settings:
•P0.00 and P0.01 are used for the 32.768 kHz crystal and are not available on the connectors.
See 32.768 kHz crystal on page 17 for more information.
•P0.05, P0.06, P0.07, and P0.08 are used by the UART connected to the interface MCU. See
Virtual COM port on page 6 for more information.
•P0.09 and P0.10 are by default used by NFC1 and NFC2. See NFC antenna interface on page
20 for more information.
•P0.13–P0.20 are by default connected to the buttons and LEDs. See Buttons and LEDs on page
14 for more information.
When the nRF52 DK is used as a shield together with an Arduino standard motherboard, the Arduino
signals are routed as shown in the following figure.
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Hardware description
Figure 11: Arduino signals routing on the nRF52 DK
4.5 Buttons and LEDs
The four buttons and four LEDs on the nRF52 DK are connected to dedicated GPIOs on the nRF52832 SoC.
Part GPIO Short
Button 1 P0.13 -
Button 2 P0.14 -
Button 3 P0.15 -
Button 4 P0.16 -
LED 1 P0.17 SB5
LED 2 P0.18 SB6
LED 3 P0.19 SB7
LED 4 P0.20 SB8
Table 3: Button and LED connection
If P0.17–P0.20 are needed elsewhere, the LEDs can be disconnected by cutting the short on SB5–SB8. See
the following figure for more information.
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Hardware description
Figure 12: Disconnecting the LEDs
The LEDs and buttons can also be disconnected by using the I/O expander as described in I/O expander for
buttons and LEDs on page 15.
The buttons are active low, which means that input is connected to ground when the button is activated.
The buttons have no external pull-up resistor, so the P0.13—P0.16 pins must be configured as input with
an internal pull-up resistor to use the buttons.
The LEDs are active low, meaning that writing a logical zero (0) to the output pin illuminates the LED.
Figure 13: Button and LED configuration
4.5.1 I/O expander for buttons and LEDs
The onboard GPIOs for the buttons and LEDs can conflict with boards that follow the Arduino standard.
Therefore, the nRF52 DK has an I/O expander to avoid such conflicts.
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Hardware description
GPIO Part Arduino signal
P0.13 Button 1 D2
P0.14 Button 2 D3
P0.15 Button 3 D4
P0.16 Button 4 D5
P0.17 LED 1 D6
P0.18 LED 2 D7
P0.19 LED 3 D8
P0.20 LED 4 D9
Table 4: GPIO connection
The I/O expander releases these GPIOs for general use when the nRF52 DK is used together with boards
that follows the Arduino standard. The I/O expander can be permanently enabled by shorting solder
bridge SB18, or permanently disabled by cutting the shorting track on SB19. You must also short SB18
when cutting SB19 for full compatibility with the Arduino standard.
The I/O expander can be temporarily enabled by connecting SHIELD DETECT to ground.
Figure 14: Enable or disable I/Os for Arduino standard
In addition to the buttons and LEDs, the following GPIOs are used for the I/O expander:
I/O expander signal GPIO
/INT P0.17
SDA P0.26
SCL P0.27
Table 5: I/O expander connection
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Hardware description
Figure 15: I/O expander schematic
Note: Software debouncing is not needed when using the I/O expander. Each button on the nRF52
DK is equipped with a debouncing filter.
4.6 32.768 kHz crystal
The nRF52832 SoC can use an optional 32.768 kHz crystal (X2) for higher accuracy and lower average
power consumption.
On the nRF52 DK, P0.00 and P0.01 are used for the 32.768 kHz crystal by default and are not available as
GPIO on the connectors.
Note: When using ANT/ANT+, the 32.768 kHz crystal (X2) is required for correct operation.
If P0.00 and P0.01 are needed as normal I/Os, then the 32.768 kHz crystal can be disconnected and the
GPIO routed to the connectors. Cut the shorting track on SB1 and SB2, and solder SB3 and SB4. See the
following figure for reference.
Figure 16: Configuring P0.00 and P0.01
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Hardware description
Figure 17: 32.768 kHz crystal and SB1–SB4
4.7 Debug input
The Debug in connector (P18) makes it possible to connect external debuggers for debugging while
running on battery or external power supply.
Figure 18: Debug input
4.8 Debug output
The nRF52 DK supports programming and debugging external boards with nRF51 Series or nRF52 Series
SoCs. To debug an external board with SEGGER J-Link OB IF, connect to the Debug out connector (P19)
using a 10-pin cable.
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Hardware description
Figure 19: Debug output connector
When the external board is powered, the interface MCU detects the supply voltage of the board and
programs/debugs the target chip on the external board instead of the onboard nRF52832 SoC.
Note: The voltage supported by external debugging/programming is 3.0 V.
You can also use P20 as a Debug out connection to program shield-mounted targets. For the Debug out
header (P19), the interface MCU detects the supply voltage on the mounted shield and programs or
debugs the target.
If the interface MCU detects target power on both P19 and P20, it programs or debugs the target
connected to P19 by default.
4.9 Connectors for programming external boards
The tables describe pinouts of connectors P19 and P20. The voltage on the external board must match
that of the DK.
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Hardware description
Pin number Signal Description
1 EXT_VTG Voltage supply from the external target,
used as voltage detect input to the interface
MCU
2 EXT_SWDIO Serial Wire Debug (SWD) data line
3 GND Ground
4 EXT_SWDCLK SWD clock line
5 GND Ground
6 EXT_SWO Serial Wire Output (SWO) line
7 N.C. Not used
8 N.C. Not used
9 EXT_GND_DETECT Ground detect. Should be connected to
ground on the external board
10 EXT_RESET Reset
Table 6: Pinout of connector P19 for programming external targets
Pin number Signal Description
1 VDD_nRF Used for current measurement
2 VDD_nRF’ Used for current measurement
3 SH_VTG Voltage supply from the external target, used
as voltage detect input to the interface MCU
4 SH_SWDIO Serial Wire Debug (SWD) data line
5 SH_SWDCLK SWD clock line
6 SH_SWO Serial Wire Output (SWO) line
7 SH_RESET Reset line
8 SH_GND_DETECT Ground detect. Should be connected to
ground on the external board
Table 7: Pinout of connector P20 for programming target on shields
4.10 NFC antenna interface
The nRF52 DK supports an NFC tag.
NFC-A Listen Mode operation is supported on the nRF52832 SoC. The NFC antenna input is available on
connector P23 on the nRF52 DK.
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