EAGLE MATRIX SVN-840C User manual

SVN-840C Development Board
Getting Started Guide
Eagle Matrix Co., Ltd. Copyright @2019
Introduction
The SVN-840C Development Board is an excellent
starting point for any Bluetooth project. All the
features of the SVN-840C can be accessed and used
by this product. These features include an NFC
connector, push buttons, LED, multiple power
configurations, full GPIO access, and more. As well as
the use of Arduino R3 layout for ease of access and
interchange ability of Arduino shields
Firmware can be developed for many applications. To
develop firmware, you will need Nordics
recommended development environment. A Nordic
nRF52 DK or debug interface such as the SEGGER J-
link Debug Probe allows for easy programming via
the Serial Wire Debug interface.
Features
•SVN-840C Module
•Virtual COM port over USB
•USB Connection to Module
•Coin Cell Battery Holder
•Full GPIO pin out of the
nRF52840
•NFC Antenna Connector
•5 Buttons and 4 LEDs
•32.768kHz Low Frequency
Crystal
Version 0.97
* Final Product Label will be Laser Etched

SVN-840C Development Board
Getting Started Guide
Eagle Matrix Co., Ltd. Copyright @2019
Hardware Description
Figure 1: SVN-840C Development Board Top View
Programming and Firmware Development
This section will guide you on how to set up and program a Blinky LED example using the SVN-
840C Development Board as well as some of the software and hardware tools needed to achieve
this. In general, any Serial Wire Output (SWO) set up should be able to program or debug the SVN-
840C Development Board.
Tools for Development
Software Tools
Here are 3 examples of useful tools for development of the nRF52840 and SVN-840C module. Not
all of these tools are needed depending on what software and hardware is used.
•Nordic nRFgo Studio
oThis is a software used to program and configure Nordic nRF devices. It supports
programming of nRF52 applications, bootloader, and soft devices. This tool needs
a SEGGER J-link programming interface to work correctly. Available at:
LED 1-4
DS1-4
NFC Antenna
Connector
J3
SVN-840C
Module
U1
Power Switch
SW1
Push Button 1-4
B1-4
Ext. Power
P9
Power
Indicator LED
High Voltage Current
Measure
P10
10 pin Tag Connector
J4
10 pin Cortex Debug
Connector
P8
Coin Cell
BT1
P7
JTAG 20 Pin
Connector
Normal voltage
Current Measure
P11
USB to Module
Connector
J2
USB Virtual COM Port
Connector
J1
Breakout
Connectors
Breakout Connectors
Low Frequency
Crystal
32.768kHz
Reset Button
B5
* Final Product Label will be Laser Etched

SVN-840C Development Board
Getting Started Guide
Eagle Matrix Co., Ltd. Copyright @2019
https://www.nordicsemi.com/Software-and-Tools/Development-Tools/nRFgo-
Studio
•Keil MDK-ARM Development Kit
oKeil is a development environment design for microcontroller applications. It is
recommended by Nordic and allows for development using the nRF52 SDK
application and examples. It can also program using a Keil U-link or SEGGER J-link
programming interface. Available at: http://www2.keil.com/mdk5/
•SEGGER J-link Software
oThis software and documentation is used with the SEGGER J-link programming
interface directly. Available at: https://www.segger.com/downloads/jlink/#J-
LinkSoftwareAndDocumentationPack
Hardware tools
There are 3 ways to connect to the SVN-840C for programming and debugging. The connectors
shown in Figure 1 as P7, P8, and J4.
The JTAG 20 Pin Connector P7 can be used with any 20 pin 2.54mm (0.1”) spacing connector.
The 10 pin Cortex Debug Connector P8 can be used with any 10 pin 1.27mm (0.05”) spacing
connector.
The 10 pin Tag Connector J4 can be used with any 10 pin Tag connector or adaptor.
Example of cables and adaptors when using a J-Link Debug Probe are found below at these links:
https://www.segger.com/products/debug-probes/j-link/accessories/adapters/9-pin-cortex-m-
adapter/
https://www.segger.com/products/debug-probes/j-link/accessories/adapters/10-pin-needle-
adapter/
nRFgo Studio Tool Set up
•Download the latest Nordic Semiconductor nRF5 SDK from
https://www.nordicsemi.com/eng/Products/Bluetooth-low-energy/nRF5-SDK
(Current version is 15.2.0) and then extract the SDK.
•Install Nordic nRFgo Studio and related utilities from the link above. Not further set up is
required.
If you wish to use the other tools please follow their guidelines on setting them up. At this point
the environment is set up and ready to program and develop for the SVN-840C.
PC to SVN-840C Interface
To connect and program with the SVN-840C development board you need to connect to one of
the connectors J4, P8, or P9. These connectors can connect to a PC via a J-link debug probe or a
virtual substitute such as the Nordic nRF52 DK.

SVN-840C Development Board
Getting Started Guide
Eagle Matrix Co., Ltd. Copyright @2019
When using the Nordic nRF52 DK it is possible to power the SVN-840C development board via the
10-pin connector P8 or Tag connector J4. The Nordic DK manual explains how to provide external
power when programming.
The J-Link debug probe can also provide power if it is set to output 5V. By default, the J-Link probe
does not power the SVN-840C development board. The development board needs to be powered
by another source, such as USB or a battery, to allow for programming or debug.
It is possible to also communicate with the SVN-840C development board via UART over USB
virtual COM port. Firmware which uses UART to communicate must loaded onto the development
board. You can not program over the UART lines. The driver for the USB to UART virtual COM port
is found here: https://www.silabs.com/products/development-tools/software/usb-to-uart-bridge-
vcp-drivers
Programming an Example on the SVN-840C
The SVN-840C development board should be connected to the Nordic nRF52 DK via a 10-pin cable
as shown in Figure 2.
Figure 2: Example of Nordic DK to SVN-840C
Programming Example 1 J-Link Emulator Drag and Drop
To program a simple Blinky LED example using Nordic Semi 15.2.0 SDK examples is easy and fast.
Step 1. Connect the SVN-840C development board and Nordic nRF52 DK as shown in Figure 2 to
your PC via the left side USB on the nRF52 DK. If the board is powered from any power source the
nRF52 DK will auto detect the SVN-840C development board and be ready for programming.

SVN-840C Development Board
Getting Started Guide
Eagle Matrix Co., Ltd. Copyright @2019
Note: If you wish to power the development board from the nRF52 DK please follow Nordics
instructions on how to supply external power via the debug out connector in the top left of the
nRF52 DK.
Step 2. Copy the Blinky LED hex file from the SDK located where you extracted the SDK.
Example with SDK 15.2.0: C:/…/nRF5_SDK_15.2.0_9412b96\examples\peripheral\blinky\hex
Step 3. Paste the hex file in the JLINK drive assigned by your computer as shown in Figure 3 below.
It will be automatically programed to the SVN-840C development board and you should see the
LEDs blinking. The Blinky LED example is shown below in Figure 5 with LEDS 1, 2, and 3 on
Figure 3: Nordic DK JLINK Drive Flasher
Programming Example 2 nRFgo Studio
To program the same example using nRFgo Studio is also easy and fast.
Step 1. Connect the SVN-840C development board as shown in Figure 2. The same set us as in step
1 of the previous programming example to your PC. Please refer to note in example 1 step 1.
Step 2. Open nRFgo Studio on your PC and nRF52 development dongles should up on the bottom
left under Device Manager. Select the J-Link driver under this section. The window should look like
this in Figure 4.

SVN-840C Development Board
Getting Started Guide
Eagle Matrix Co., Ltd. Copyright @2019
Figure 4: nRFgo Studio Window for Programming
Step 3. Select Program Application. Browse and load the same Blinky LED example as in the
previous programming example. The hex file from the SDK is located where you extracted the SDK.
Example with SDK 15.2.0: C:/…/nRF5_SDK_15.2.0_9412b96\examples\peripheral\blinky\hex
Step 4. If the chip is not erased, press Erase all. Once this is one press Program to program the
Blink LED example. Once it is completed it should automatically start and the LEDs will be blinking.
The Blink LED example is shown below in Figure 5 with LEDS 1, 2, and 3 on.
Figure 5: Blinky LED Example on SVN-840C Development Board

SVN-840C Development Board
Getting Started Guide
Eagle Matrix Co., Ltd. Copyright @2019
Powering the Board
Power Settings Quick Reference
Power Source
Mode
SW1
Position
Solder Bridges
USB
High Voltage
VBUS
SB20 Closed
USB
Normal voltage
VDD
SB3 Closed
Coin Cell
Normal voltage
VDD
SB17 Closed
External Power <3.7V
High Voltage
VEXT
SB22 Open, SB23 Open
External Power <3.7V
Normal voltage
VDD
SB3 Closed, SB22 Open, SB23 Closed
External Power >3.7V
Normal voltage
VEXT
SB22 Closed, SB23 Open
JTAG 20 Pin
High Voltage
VBUS
SB20 Closed, SB24 Closed
JTAG 20 Pin
Normal voltage
VDD
SB3 Closed, SB19 Closed
JTAG 10 Pin
Normal voltage
VDD
SB18 Closed
JTAG 10 Pin Tag
Normal voltage
VDD
SB18 Closed
Power Configurations
The board can be powered from several different sources: Coin Cell battery (BT1), USB Connect
(both J1 and J2 not simultaneously), External Power (P9) such as a battery, and any connector (J4,
P8, P7) that can provide power. The power source is selectable with SW1 in 3 main modes. VBUS
for high voltages modes such as the USB or J-LINK 5V output. VDD is for normal voltage modes.
VEXT is for the external power source. There is an LED near SW1 to indicate power and can be
disconnected by cutting SB12 if needed. When only using normal voltage mode L1 can be
disconnected if needed by cutting SB16. L1 must always be connected for high voltage mode.
Note: There are no protection circuits on the coin cell. If you are using a coin cell, please remove it
before switching to another power source.
U3, the UART to USB bridge, contains a low drop out regulator to 3.3V. By default, this regulator is
disconnected from the common normal voltage power plane. To use this voltage regulator and
power the SVN-840C from a high voltage power source in normal voltage mode connect solder
bridge SB3 near the USB connector J1 on the left side of Figure 1. Then select VDD mode from SW1
to power from the 3.3V regulator output.
External power can be provided from any DC power source. Such as 2 AA batteries, a Li-Po battery,
or a DC power supply. External power can provide both high voltage and normal voltage power
settings with the correct connections of solder bridges. When using a high voltage battery such as
a Li-Po have both solder bridge SB22 and SB23. If you wish to use a high voltage source but use
low voltage mode, the 3.3V regulator can be used to supply 3.3V low voltage mode. This is done
by connecting solder bridge SB3 and SB23 and setting SW1 to VDD mode. To use any normal
voltage source from 1.7 to 3.7V in normal voltage mode connect solder bridge SB22 and stay in
VEXT mode on SW1.

SVN-840C Development Board
Getting Started Guide
Eagle Matrix Co., Ltd. Copyright @2019
All of the normal voltage VDD power sources can be disconnected or isolated from the common
VDD by cutting or unsoldering the solder bridges SB3, SB17 (Near Coin Cell), SB18 (Between 10 pin
Cortex Connector and Tag connectors), SB19 (Near JTAG 20 pin Connector). The VBUS or 5V power
plane can be disconnected from the power switch SW1 by cutting solder bridge SB20.
Low Frequency Crystal
By default, the low frequency crystal is connected to the SVN-840C module as shown in Figure 1.
The allows for the most clock modes to be used. The crystal can be disconnected, and the pins can
be used as GPIO pins. The crystal is connected to the module by shorted solder bridges SB1 and
SB2. The GPIO are connected by open solder bridges SB8 and SB9. To use the GPIO please cut SB1
and SB2 and connect SB8 and SB9.
NFC Antenna Connector
By default, the NFC connector is not connected to the SVN-840C and is instead connected to GPIO.
If you wish to use the NFC connector, please move the 0R resistors R7 and R8 to series pads C12
and C13.
Note: Because the NFC is not connected by default any Nordic SDK examples that use NFC will
need to have the 0R resistors moved for the to be NFC connected.
LEDs
4 LEDs are provided on the SVN-840C Development Board. These green LEDs are connected to the
pins of the SVN-840C module similarly as the Nordic nRF52 DK, sharing the same pins. They are
connected to the VDD plane and are active low, the GPIO needs to be enabled for high drive when
you wish to use these. They can be disconnected from the module by cutting solder bridges SB4,
SB5, SB6, and SB7.
Note: All LEDS require a minimum of 2V in the VDD to turn on, if you are operating under 2V it is
not possible to use the LEDS on the development board including the power indicator LED.
Push Buttons
There are 4 push buttons connected to the SVN-840C Development Board. They are connected to
the pins of the SVN-840C module similarly as the Nordic nRF52 DK, sharing the same pins. The
push buttons are all active low and connect to ground when pressed. The button pins need to be
set with the internal pull-up resistors to work properly.
High and Normal Voltage Current Measure
The current of the SVN-840C development board can be measured in high voltage mode using the
connector P10 near power switch SW1. To measure the current solder bridge SB14 must be cut
and an Ammeter can be placed in series using P10.

SVN-840C Development Board
Getting Started Guide
Eagle Matrix Co., Ltd. Copyright @2019
The normal voltage current measure works similarly with the connector P11 near the SVN-840C
Module. Solder bridge SB15 must be cut and an Ammeter can be placed in series using P11.
USB to UART Virtual COM Port
The USB connector J1 at the far left of the board in Figure 1 can be used as a virtual com port for
communicating with the SVN-840C. The UART connections are by default with no hardware flow
control. If you wish to use the UART pins as GPIO or with control flow, please cut solder bridges
SB12 and SB13 near the USB to UART control chip U3. Then solder the solder bridges SB11 and
SB10. Pin P0.08 is RX and Pin P0.06 is TX, Pin P0.07 is CTS and Pin P0.05 is RTS for control flow.
SWO Debug and Programming Interface
There are 3 connectors for a SWO debug and programming interface to connect to the SVN-840C
with. A tag connector J4, a 10 pin Cortex Connector P8, and a 20-pin connector P7. More detail on
how to use these are described in the programming and firmware section.
Breakout Connectors
There are several breakout connectors for access to the GPIO of the SVN-840C. The connectors P1,
P2, P3, and P4 are Arduino shield compatible. The breakout connectors pinout are labeled for ease
of access to the GPIO.
Note: The 5V pad in connector P4 only provides 5V if the USB or another 5V source is connected to
the SVN-840C Development Board.
Reset Button
There is a Reset push button connected to the SVN-840C Development Board and shares the same
pin as the Nordic nRF52 DK, Pin P0.18. The Reset button is active low and connects to ground
when pressed. The button pin needs to be set with the internal pull-up resistor to work properly.
This reset will work with Nordic SDK examples.
Revision History
Revision
Number
Changes and Notes
Date
0.9
Initial Release
2018/11/13
0.91
Added Power Quick Reference
2018/11/16
0.92
Added Note Related to Coin Cell
2018/11/30
0.93
Added Reset Button Information
2018/12/04
0.94
Updated Power Label References
2018/12/06
0.95
Updated Trademark
2018/12/06
0.96
Updated Pictures and References
2019/01/17
0.97
Updated Labeling, Reference, Pictures, and notes.
2019/01/21