Nordic Semiconductor nRF52 Preview Development Kit User manual

nRF52 DK Hardware
v3.x.x
User Guide
4397_500 / 2023-04-11

Contents
Revision history.................................. iii
Environmental and safety notices.......................... v
1Introduction................................... 6
2Kit content.................................... 7
3Interface MCU.................................. 8
3.1 Reset button .................................. 8
3.2 Virtual serial port ................................ 8
3.2.1 Dynamic Hardware Flow Control ........................ 9
3.3 Mass Storage Device ............................... 9
4Hardware description............................. 11
4.1 Hardware drawings ............................... 11
4.2 Block diagram ................................. 12
4.3 Power supply ..................................12
4.4 Connector interface ............................... 15
4.5 Buttons and LEDs ................................ 16
4.5.1 I/O expander for buttons and LEDs ....................... 17
4.6 32.768 kHz crystal ................................19
4.7 Debug input .................................. 20
4.8 Debug out for programming external boards .................... 21
4.8.1 Programming an external board ........................ 22
4.8.2 Programming a board with custom connections ..................23
4.9 NFC antenna interface .............................. 25
4.10 Solder bridge and test point overview ....................... 27
5Measuring current............................... 30
5.1 Preparing the DK ................................ 30
5.2 Using an oscilloscope for current profile measurement ................ 31
5.3 Using an ampere meter for current measurement .................. 32
6RF measurements............................... 34
Glossary ..................................... 35
Recommended reading.............................. 37
Legal notices................................... 38
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Revision history
Date Description
2023-04-11 • Updated the following chapters for nRF52 DK v3.x.x:
•Interface MCU on page 8 - Removed Mbed OB interface firmware
information
•Reset button on page 8 - Updated button function
•Virtual serial port on page 8 - Added information on two virtual serial
ports
•Dynamic Hardware Flow Control on page 9 - Added information on
UART without HWFC
•Power supply on page 12 - Updated schematic and IF MCU current
consumption information
•Programming an external board on page 22 - Updated instructions and
P19 connector pinout
•Programming a board with custom connections on page 23 - Updated
instructions and P20 connector pinout
•Table 8: Solder bridge configuration for nRF52 DK (v3.0.0 and higher) on
page 27 - Updated table contents
• Updated drawings and schematics
• Editorial changes
2023-01-05 • Updated Debug out for programming external boards on page 21
• added:
•Programming an external board on page 22
•Programming a board with custom connections on page 23
• Editorial changes
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 6
• Software tools
•Measuring current on page 30
•Preparing the DK on page 30
February 2017 • Created PDF for nRF52 DK v1.1.x (valid for all DK versions)
• Added Mass Storage Device on page 9
• Updated:
4397_500 iii

Revision history
Date Description
•Interface MCU firmware
•Solder bridge and test point overview on page 27
Previous versions
PDF files for relevant previous versions are available here:
•nRF52 DK User Guide v2.x.x
•nRF52 DK User Guide v1.3.1
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Environmental and safety notices
Environmental and safety notices for the DK and power supply requirements.
Note: The nRF52 DK must be powered by a PS1 class (IEC 62368-1) power supply with maximum
power less than 15 W.
Skilled persons
The nRF52 DK is intended for use only by skilled persons.
A skilled person is someone with relevant education or experience that enables them to identify potential
hazards and takes appropriate action to reduce the risk of injury to themselves and others.
Electrostatic Discharge
The nRF52 DK is susceptible to Electrostatic Discharge (ESD).
To avoid damage to your device, it should be used in an electrostatic free environment, such as a
laboratory.
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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.
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 a virtual serial port
• Drag-and-drop Mass Storage Device (MSD) programming
• Support for NFC-A Listen Mode
• Pins for measuring power consumption
To get started, see the Software development Getting Started Guides. For more detailed documentation
regarding nRF52810 development, see Developing for nRF52810 in the SDK documentation.
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 Onboard (OB) interface firmware and is used to
program and debug the firmware of the nRF52832 SoC.
Figure 2: Interface MCU
3.1 Reset button
The nRF52 DK has a Reset button (SW5).
This button is connected to the interface MCU on the DK and resets the nRF52832 SoC or any device
connected to the external programming connectors.
For the reset button to work, pin reset on P0.21 must be enabled in the embedded firmware of the
nRF52832SoC.
3.2 Virtual serial port
The interface MCU features a Universal Asynchronous Receiver/Transmitter (UART) interface through a
virtual serial port. One port is connected to the physical port on the DK, and the other is not usable.
The virtual serial port has the following features:
• Flexible baud rate setting up to 1 Mbps (baud rate 921,600 bps is not supported)
• Optional Hardware Flow Control (HWFC)
• Tri-stated UART lines when no terminal is connected
The following table shows an overview of the UART connections on the nRF52832 SoC and the interface
MCU.
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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 serial 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.
3.2.1 Dynamic Hardware Flow Control
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 P0.07 and P0.05 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 serial 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.
P0.05 (RTS) and P0.07 (CTS) can be disconnected from the interface MCU by switching SW7 to OFF.
This might be necessary if UART without HWFC is needed while P0.05 (RTS) and P0.07 (CTS) are used
for other purposes. To ensure that the P0.06 (TXD) and P0.08 (RXD) lines are not affected by the
interface MCU, the solder bridges for these signals can be cut and later resoldered if needed.
3.3 Mass Storage Device
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 the drive.
When a HEX file is copied to the drive, the interface MCU programs the file to the DK.
You can 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.
Troubleshooting MSD operation
• If Windows tries to defragment the MSD, the interface MCU disconnects and becomes unresponsive.
To return to normal operation, power cycle the DK.
• Your antivirus software might try to scan the MSD. 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.
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Interface MCU
• If the computer is set up to boot from USB, it can try to boot from the DK if it is connected. This can
be avoided by unplugging the DK before a computer restart or changing the boot sequence of the
computer.
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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 serial 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
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Hardware description
Figure 4: nRF52 DK (PCA10040) back view
4.2 Block diagram
The block diagram illustrates the nRF52 DK functional architecture.
External supply Current
measurement
IF MCU USB
Battery
Buttons
Voltage regulator
LEDs
GPIO
nRF52832Interface MCU
VBUS
Data
Osc
32.768 kHz
IF Boot/Reset
SWD
VDD_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
Switch
UART HWFC
UART DATA
PCB antenna
Figure 5: Block diagram
4.3 Power supply
The nRF52 DK has three power options: USB (5 V), external power supply (1.7 V to 3.6 V), and coin cell
battery.
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Hardware description
Figure 6: Power supply options (front)
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 approximately 20 mA to maintain the reset button functionality. This affects current
consumption, but not the nRF52832 current measurements, as described in Measuring current on
page 30.
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Hardware description
C18
100nF
C17
1.0µF
C16
1.0µF
Vin
GND
Vout
U3
VDD
R6
N.C.
SB9
VDD_nRFVBUS
SB10
TP14
Power switchVoltage regulator nRF current measurementReverse voltage protection
VBUS'V5V TP12
TP13
Instrument ground
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
Q4B
Q5A
Q5B
Q3A
Q3B
R50
220k
R51
220k
D7
D1
GND
VCC
U12
NC7SV11L6X
GND
VCC
U13
NC7SV11L6X
VREG_DETECT
VREG_DETECT
AP7333-33
LDO
3.3V-300mA
VBUS' NT1 VBUS_IMCU
SW6
Figure 8: Power supply circuitry
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 to 3.6 V
Table 2: Protection diode bypass solder bridges
Figure 9: Protection diode bypass solder bridges
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Hardware description
Note: Connect only one power source at a 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.
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.
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 19 for more information.
•P0.05, P0.06, P0.07, and P0.08 are used by the UART connected to the interface MCU. See
Virtual serial port on page 8 for more information.
•P0.09 and P0.10 are by default used by signals NFC1 and NFC2. See NFC antenna interface on page
25 for more information.
•P0.13–P0.20 are by default connected to the buttons and LEDs. See Buttons and LEDs on page
16 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 -
LED1 P0.17 SB5
LED2 P0.18 SB6
LED3 P0.19 SB7
LED4 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 17.
The buttons are active low, which means that input is connected to ground when the button is activated.
The buttons do not have an 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.
R2
220R
R1
220R
SB6
VDD
R3
220R
SB7
R4
220R
SB8SB5
LED1'
LED2'
LED3'
LED4'
LED1 LED2 LED3 LED4
BUTTON1'
BUTTON2'
BUTTON3'
BUTTON4'
SW1
SW2
SW3
SW4
4
8
12
16
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. To
avoid such conflicts, the nRF52 DK has an I/O expander.
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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 LED1 D6
P0.18 LED2 D7
P0.19 LED3 D8
P0.20 LED4 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 follow 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
C47
100nF
VEXT
R29
4k7
R30
4k7
R31
18k
R32
18k
VEXT
BUTTON1_EXT
BUTTON2_EXT
BUTTON3_EXT
BUTTON4_EXT
LED4_EXT
LED3_EXT
LED2_EXT
LED1_EXT
R37
N.C.
R38
0R
VEXT
SDA_EXT
SCL_EXT
INT_EXT
SDA
13
VDD(I2C) 15
ADDR
16
SCL
12
RESET
1
INT
11
IO3 5
GND
6
VDD(P) 14
IO2 4
IO1 3
IO0 2
IO7 10
IO6 9
IO5 8
IO4 7
U7
PCAL6408A
I/O expander
7-bit slave address: 0x20
Figure 15: I/O expander schematic
Note: Software debouncing is not needed when using the I/O expander. Each button on the nRF52
DK has 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.
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Hardware description
Figure 16: Configuring P0.00 and P0.01
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 a battery or an external power supply.
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