Getting started with the X-NUCLEO-S2915A1 Sub-1 GHz 915 MHz RF expansion
board based on S2-LP radio for STM32 Nucleo
Introduction
The X-NUCLEO-S2915A1 expansion board is based on the S2-LP radio and operates in the 915 MHz ISM frequency band.
The expansion board is compatible with ST morpho and Arduino UNO R3 connectors.
The X-NUCLEO-S2915A1 interfaces with the STM32 Nucleo microcontroller via SPI connections and GPIO pins. Y
change some of the GPIOs by mounting or removing the resistors.
Figure 1. X-NUCLEO-S2915A1 expansion board
ou can
UM2641 - Rev 1 - November 2019
For further information contact your local STMicroelectronics sales of
fice.
www.st.com
1Acronyms and abbreviations
Table 1. List of acronyms
AcronymDescription
AMRAutomatic meter reading
EEPROMElectrically erasable programmable read only memory
GHzGiga Hertz
GUIGraphical user interface
LEDLight emitting diode
MCUMicrocontroller unit
P2PPoint-to-point communication
RFRadio frequency communication
SPISerial peripheral interface
USBUniversal serial bus
wM-BusWireless metering bus
WSNWireless sensors network
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Acronyms and abbreviations
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2Getting started
2.1Overview
The X-NUCLEO-S2915A1 main features are:
Based on S2-LP radio
•
•S2-LP narrow band ultra-low power sub-1 GHz transceiver tuned for 860-940 MHz frequency band
•Programmable RF output power up to +27 dBm
•Modulation schemes: 2-FSK, 2-GFSK, 4-FSK, 4-GFSK, OOK and ASK
•Air data rate from 0.1 to 500 kbps
•Ultra-low power consumption: 7 mA RX and 10 mA TX at +10 dBm
•IEEE 802.15.4g hardware packet support with whitening, FEC, CRC and dual SYNC word detection
•RX and TX 128 byte FIFO buffers
•Support to wireless M-Bus
•Excellent performance of receiver sensitivity (up to -130 dBm)
•Automatic acknowledgement, retransmission and timeout protocol engine
•Compatible with STM32 Nucleo boards
•Compatible with Arduino UNO R3 connectors
•Sigfox compatible
•Sample firmware for P2P communication
•6LoWPAN compatible thanks to STM32Cube
•FCC ID: S9NS2915A
•IC ID: 8976C-S2915A1
•RoHS and WEEE compliant
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Getting started
2.2Typical applications
The X-NUCLEO-S2915A1 expansion board can be used for the evaluation of the S2-LP device in multiple
applications:
•
wM-Bus application
•Point-to-point communication protocol
•6LoWPAN applications
•SigFox communication
You can develop other applications for evaluating the devices, such as:
•Automatic meter reading
•Home and building automation
•WSN
•Industrial monitoring and control
•Wireless fire and security alarm systems
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2.3Hardware and software requirements
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Hardware and software requirements
To use STM32 Nucleo development boards with the X-NUCLEO-S2915A1
as shown below.
Figure 2. X-NUCLEO-S2915A1 expansion board connected to an STM32 Nucleo development board
expansion board, connect the boards
The interconnection between the STM32 Nucleo and the X-NUCLEO-S2915A1 has been designed to allow using
any STM32 Nucleo board, although complete testing has been performed using NUCLEO-L053R8, NUCLEO-
F401RE and NUCLEO-L152RE boards hosting the ultra-low power STM32.
The following software and hardware specifications are required:
•a PC/laptop with Microsoft Windows (7 and above) to install the software package (X-CUBE-SUBG1)
•a type A USB to mini-B USB cable to connect the STM32 Nucleo board to the PC/laptop
•128 MB of RAM
•Approximately 40 MB of hard disk space for the firmware
•Approximately 15 MB of hard disk space for the wM-Bus GUI
The use of the wM-Bus concentrator with the GUI requires additional boards to be connected to the PC. The GUI
can be used to check the wM-Bus communication protocol.
2.4Board setup
Step 1.Check that the jumper on JP1 connector is connected to provide the required voltage to the board
devices.
Step 2.Connect the X-NUCLEO-S2915A1 to the STM32 Nucleo
Step 3.Power the Nucleo development board using the Mini-B USB cable.
Step 4.Program the firmware in the STM32 on the Nucleo development board using the firmware sample
provided.
Step 5.Reset the MCU board using the reset button on the Nucleo development board.
The evaluation kit is ready-to-use.
board.
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Hardware description and configuration
3Hardware description and configuration
3.1Interconnection details
The X-NUCLEO-S2915A1 expansion board and the NUCLEO-F401RE or NUCLEO-L152RE board connection
details are listed in the table below
Table 2. X-NUCLEO-S2915A1 and NUCLEO-L152RE connection details (left connector)
NCIOREFRESET3V3
CN6 PowerCN8 Analog
12345678123456
3V3GNDGNDGPIO0CSNGPIO1GPIO2
5
.
Signal name
V
GNDGNDVINA0A1A2A3A4A5
Connector name
Pin number
NUCLEO-L152RE MCU port
PA0PA1PA4PB0PC1PC0
X-NUCLEO-S2915A1 expansion board signals
GPIO0
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(1)
GPIO3
Optional connection.
1.
Table 3. X-NUCLEO-S2915A1 and NUCLEO-L152RE connection details (right connector)
The SPI and GPIO connection options between the STM32 Nucleo and S2-LP can be used to enable different
configurations in case a signal conflict occurs when using other expansion boards.
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Table 4. S2-LP interface with STM32 Nucleo board
S2-LP signalDefault STM32 portOptional STM32 port
CSnPA1
PB6
T
o use the optional connection, mount R9, unmount R13
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Current measurement
S2-LP signalDefault STM32 portOptional STM32 port
CLKPB3
nSPB4
SDNPA8
PA5
T
o use the optional connection, mount R6, unmount R11
PA9
T
o use the optional connection, mount R7, unmount R19
PB10
T
o use the optional connection, mount R18, unmount R10
To use the optional connections, modify the firmware on the basis of the STM32 resources used.
T
able 5. SKY66420 power amplifier settings
SKY66420SW1SW2
LNA ON (default)
LNA OFF
100 pF capacitor between pin1 and pin2 (pin1 and
pin3 open)
100 pF capacitor between pin1 and pin3 (pin1 and
pin2 open)
100 pF capacitor between pin1 and pin3 (pin1 and
pin2 open)
100 pF capacitor between pin1 and pin2 (pin1 and
pin3 open)
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Table 6. SKY66420 interface with STM32 Nucleo board
SKY66420 signalDefault STM32 portOptional STM32 port
GPIO0PA0
GPIO1PA4N.A.
GPIO2PB0N.A.
T
o use optional connection mount R25, unmount R12
3.3Current measurement
To monitor the X-NUCLEO-S2915A1 expansion board power consumption, use jumper J1: connect an ammeter
probe between the connector pins 1 and 2 for measurements.
3.4X-NUCLEO-S2915A1 component placement details
The figure below shows the component placement on the X-NUCLEO-S2915A1 expansion board.
The X-NUCLEO-S2915A1 expansion board is based on the S2-LP standalone RF transceiver
915 MHz ISM frequency band and wireless M-Bus.
S2-LP narrow band ultra-low power sub-1 GHz transceiver is tuned for 430-470 MHz and 860 - 940 MHz,
frequency bands and programmable RF output power up to +16 dBm.
Order codeS2-LPQTR
PackageQFN24 4x4x1
Operating voltage1.8 to 3.6 V
4.2SPI EEPROM
The M95640-R is a 64 Kbit serial SPI bus EEPROM with high-speed clock interface. The device can be used to
store the configuration parameters related to S2-LP RF device application or settings.
FeaturesDescription
Order codeM95640-RMC6TG
PackageMLP8
Operating voltage1.8 to 5.5 V
. It operates in the
Table 7. S2-LP details
FeaturesDescription
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24
C32
C_220n_04 02
15
VDDRXDIG
GND
4
C16
NP
R1
R_100k_040 2
C50
C_1p5_040 2
CSN
OUT
GPIO2
+3V3
22
C37 2p4F
GPIO0
VRRF
L10
L_5n6H_04 02
L8
L_15nH_04 02
C11
C_220n_04 02
C34
C_3p3F_040 2
SW1
1
9
2
NC
GND
NC
5
U4
SKY66420
7
L2
L_10U_060 3
VCC0
15
SW2
NC
C30
C_220n_04 02
C47
C_100p_04 02
C23 1.5pF
VDDVCOTX
3
10
C48
C_1p2_040 2
C37 2p4F
10
C8
C_100p_04 02
2
C18
NM
C24
C_100p_04 02
nS
C50
C_1p5_040 2
8
C55 33pF
VDD
RX
R44
2.2K
C61
NP
C5
C_220n_04 02
SDN
25
3
VDDSMPS
GND
U5
STSAFE-A100
18
L24
4n7H
L26
7n5H
C31
2p2F
R1
R_100k_040 2
C9
C_100n_04 02
L27
2n7H
C36
C_220n_04 02
C17
100pF
R3
R_100k_040 2
C56 1nF
C44
C_2p7F_040 2
C9
C_100n_04 02
SDA
L7
L_4n7H_04 02
VDD
1. 4 V t o 1. 8 V max
C
C61
NP
7
6
7
ANT
13
4
SW2
9
L3
L_39nH_04 02
CPS
5
TX_ALT
L13
L_18nH_04 02
2
C46
C_100p_04 02
C12
C_1u_0402
L9
L_6n8H_04 02
1
C6
C_100p_04 02
C38
NP
C51
C_100p_04 02
GND
16
R3
R_100k_040 2
14
SDA
R45 2.2K
C58 120pF
C41
C_100p_04 02
C55 33pF
LNA ON: SW1 soldered a 100 pF cap between 1 - 2
SW2 soldered a 100 pF cap between 1 - 3
LNA OFF: SW1 soldered a 100 pF cap between 1 - 3
SW2 soldered a 100 pF cap between 1 - 2
Ultra-low power,
high performance,
sub-1GHz
transceiver
860 to 930 MHz RF
front-end module
Authentication and
brand protection
secure solution
(not mounted)
KemetC0402C101J3GACTU
STM95640-RMN6
STS2-LPQTR
SkyworksSKY66420-11
STSTSAFE-A100
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Formal notices required by the U.S. Federal Communications Commission ("FCC")
7Formal notices required by the U.S. Federal Communications
Commission ("FCC")
FCC NOTICE: This device complies with part 15 of the FCC Rules. Operation is subject to the following two
conditions: (1) This device may cause harmful interference, and (2) this device must accept any interference
received, including interference that may cause undesired operation.
Changes or modifications not expressly approved by the manufacturer could void the user
the equipment.
Additional warnings for FCC
This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to part
15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a
residential installation. This equipment generates, uses and can radiate radio frequency energy and, if not
installed and used in accordance with the instructions, may cause harmful interference to radio communications.
However, there is no guarantee that interference will not occur in a particular installation. If this equipment does
cause harmful interference to radio or television reception, which can be determined by turning the equipment off
and on, the user is encouraged to try to correct the interference's by one or more of the following measures:
•Reorient or relocate the receiving antenna.
•Increase the separation between the equipment and the receiver.
•Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
•Consult the dealer or an experienced radio/TV technician for help.
’s authority to operate
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Formal product notice required by the Industry Canada ("IC")
8Formal product notice required by the Industry Canada ("IC")
Innovation, Science and Economic Development Canada Compliance - This device complies with Innovation,
Science and Economic Development RSS standards. Operation is subject to the following two conditions: (1) this
device may not cause harmful interference, and (2) this device must accept any interference received, including
interference that may cause undesired operation. Changes or modifications not expressly approved by the
manufacturer could void the user
Conformité à Innovation, Sciences et Développement Économique Canada - Cet appareil est conforme aux
normes RSS d'Innovation, Science et Développement économique. L'utilisation est soumise aux deux conditions
suivantes: (1) cet appareil ne doit pas causer d'interférences nuisibles, et (2) cet appareil doit accepter de
recevoir tous les types d’interférence, y comprises les interférences susceptibles d'entraîner un fonctionnement
indésirable. Les changements ou les modifications non expressément approuvés par le fabricant pourraient
annuler le permis d'utiliser l'équipement.
’s authority to operate the equipment.
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Revision history
able 9. Document revision history
T
DateRevisionChanges
18-Nov-20191Initial release.
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UM2641
Contents
Contents
1Acronyms and abbreviations ......................................................2
2Getting started ....................................................................3
Figure 6. X-NUCLEO-S2915A1 circuit schematic - ST morpho connectors.................................10
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