ATIM ARM-N8-LRW User manual

General information:
•Frequency: 868MHz, 915MHz
•LoRaWAN
•LoRa P2P
•Standalone
•RF data rate: 100 to 10000 bps
•Modulation: CSS
•Output power: 2 to 20 dBm
•Sensitivity: -142 dBm
•Link budget: 161dB
•Range up to: 25km
•Interface: UART
•Dimensions: 30mm x 18mm
•Certified: EN 300 220
•Operating temperature: -20°C /+85°C
Typical application:
•Internet Of Things (IoT)
•Environment
•Intelligent structures
•Telemetry
•Alarm and wireless security
systems
•M2M
•Remote sensors
USER GUIDE
Transceiver 868MHz : 14/20dBm
ARM-N8-LRW
MODULE

Document Information
File name
EN-UG -ARM-N8-LRW
Created
04/07/2018
Total pages
62
Version
Notes
Firmware supported
V1.1
First preliminary release (2018-07-04 TDX)
ARM-N8-LRW_3-2-3_ACW-RTU_v2-0-0_BL_ENC.bin
V1.2
Second preliminary release (2018-12-10 TDX)
ARM-N8-LRW_3-2-3_ACW-RTU_v2-0-0_BL_ENC.bin

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SUMMARY
1GENERAL DESCRIPTION...............................................................................................6
2Technical features ............................................................................................................7
2.1 BLOCK DIAGRAM .............................................................................................................7
2.2 Dimensions ........................................................................................................................7
2.3 Pinout .................................................................................................................................8
2.4 Electrical characteristics ....................................................................................................9
2.5 Link interfaces....................................................................................................................9
2.6 Power supply......................................................................................................................9
2.7 Impedance of the antenna MATCHING...........................................................................10
2.8 FOOTPRINT AND GROUND PLAN ................................................................................10
2.9 ELECTROSTATIC DISCHARGE.....................................................................................11
2.10 Material information .........................................................................................................11
2.11 RECOMMENDED SOLDERING REFLOW PROFILE.....................................................11
2.12 Moisture sensitivity...........................................................................................................12
3Overall organization........................................................................................................13
3.1 LoRa M2M........................................................................................................................13
3.2 LoRaWAN ........................................................................................................................13
3.3 Transparent UART/RF BRIDGE ......................................................................................13
3.4 Standalone mode.............................................................................................................13
3.5 COMMAND MODE ..........................................................................................................14
Distant .......................................................................................................................................................14
3.6 TEST MODE ....................................................................................................................14
4Device organization ........................................................................................................15
4.1 Memory ............................................................................................................................15
4.1.1 Memory footprint and buffers ......................................................................................................15
4.2 Registers ..........................................................................................................................16
4.2.1 Registers organization.................................................................................................................16
5Main parameters (LORA M2M & LORWAN)..................................................................18
5.1 UART................................................................................................................................18
5.1.1 AT commands .............................................................................................................................18
5.2 Transparent UART/RF BRIDGE ......................................................................................19
5.3 Low Power mode .............................................................................................................19
5.4 Delays ..............................................................................................................................21
5.5 Postamble ........................................................................................................................22
5.6 Led behavior ....................................................................................................................22
5.7 Test mode ........................................................................................................................22
5.7.1 Battery level (ATT08) ..................................................................................................................23

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RSSI reader (ATT09) ................................................................................................................................23
Continuous RSSI reader (ATT0A) ............................................................................................................23
5.7.2 Periodic emission (ATT0E)..........................................................................................................23
5.8 CONFIGURATION:..........................................................................................................24
6LoRaWAN.......................................................................................................................26
6.1 Generalities......................................................................................................................26
6.1.1 • Bidirectional endpoint (Class A):...............................................................................................27
6.1.2 • Bidirectional endpoint with programed receive windows (Class B):.........................................27
6.1.3 • Bidirectional endpoint with continuous reception (Class C): ....................................................27
6.2 Communication ................................................................................................................27
6.2.1 • UnConfirmed frame:..................................................................................................................27
6.2.2 • Confirmed frame:.......................................................................................................................27
6.3 Radio frequencies characteristics....................................................................................28
6.4 Radio................................................................................................................................28
6.4.1 Choosing the LoRaWAN class....................................................................................................28
6.5 Main parameters ..............................................................................................................28
6.5.1 OTAA process .............................................................................................................................30
6.5.2 Advanced parameters .................................................................................................................30
6.6 LoRaWAN parameters (Read only) .................................................................................34
6.7 Advanced options ............................................................................................................35
6.7.1 DL_REC functionnality ................................................................................................................35
6.7.2 EMIT_CYCLE functionnality........................................................................................................36
6.7.3 Alive frame...................................................................................................................................36
6.7.4 Logs.............................................................................................................................................37
6.7.5 Examples .....................................................................................................................................37
7lora p2p...........................................................................................................................38
7.1 RF Specification...............................................................................................................38
7.1.1 REVERSAL TIME........................................................................................................................39
7.2 UART Configuration.........................................................................................................39
7.3 Serial buffers....................................................................................................................40
7.4 Transparent (SERIAL/RF BRIDGE).................................................................................42
7.4.1 Configuration ...............................................................................................................................42
7.4.2 Functioning ..................................................................................................................................42
VariablePacket..........................................................................................................................................43
7.5 MAIN PARAMETERS ......................................................................................................44
7.5.1 RF CONFIGURATION IN P2P MODE ........................................................................................44
7.5.2 Low Data Rate Optimization........................................................................................................45
7.6 LoRaTM Packet Structure................................................................................................46

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7.6.1 Preamble .....................................................................................................................................46
7.6.2 Variable packet LoRa-Header Mode...........................................................................................46
7.6.3 Fixed packet LoRa-Header Mode ...............................................................................................46
7.6.4 SyncWord ....................................................................................................................................47
7.6.5 Low Data Rate Optimization........................................................................................................47
7.6.6 Lora-Payload ...............................................................................................................................47
7.6.7 Address........................................................................................................................................48
7.6.8 User payload ...............................................................................................................................49
7.7 LBT (Listen Before Talk) ..................................................................................................49
7.8 LBT&AFA (Adaptative Frequency Agility)........................................................................50
Exemple : ..................................................................................................................................................50
7.9 SNIFF MODE ...................................................................................................................51
7.10 Repeater ..........................................................................................................................52
7.10.1 Unidirectional configuration:....................................................................................................52
7.10.2 Bidirectional configuration:......................................................................................................52
7.11 Description of the Registers.............................................................................................53
7.12 Radio channels ................................................................................................................54
7.13 test MODE........................................................................................................................56
7.13.1 PING PONG MODE: ...............................................................................................................56
7.13.2 RSSI READING: ATT0A/ATT02 OR ATS000=0A/ATS000=02..............................................57
7.13.3 PUR CARRIER MODE: ATT04 or ATS000=04 ......................................................................57
7.13.4 CONTINUOUS MODULATION: ATT07 or ATS000=07 .........................................................58
7.13.5 TRANSIENT MODE: ATT08 or ATS000=08...........................................................................58
7.14 EXAMPLE ........................................................................................................................59
7.14.1 RX MODE WITH RSSI READING ..........................................................................................59
7.14.2 ADRESS MODE......................................................................................................................59
7.14.3 REPEATER IN BIDIRECTIONAL CONFIGURATION+ADRESS MODE ...............................61

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1GENERAL DESCRIPTION
E
Figure 1
The N8-LRW is a radio module using LoRa modulation that guarantees high immunity to interference, and a very low
sensitivity in reception. These characteristics which make it possible to reach a very long range.
The N8-LRW is a dual-mode module, capable of working on both LoRaWAN and Lora M2M. It can be operated under M2M
or LoRaWAN modes, or under both modes simultaneously. Under LoRaWAN, the module can be used in either class A or
class C. Under Lora M2M, the module can be operated in ENSI or FCC.
The N8-LRW module is pin-to-pin compatible with other modules from ATIM. It has taken over all features of the ARM N8-
LW model. Other UART / BRIDGE mode, the N8-LRW embarks a so-called "Standalone" mode, enabling users to directly
connect it to sensors without going through an external microcontroller. You will find usage examples on a note app. The
Standalone mode allows for the integration of a new connected device in a very short time, even for users not familiar with
embedded programming. The Standalone mode can be used under both LoRaWAN and LoRa P2P.
LoRa : EU / FCC
LoRaWan : EU
Classe A,C
UART // RF BRIDGE
STANDALONE MODE
N8LRW

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2TECHNICAL FEATURES
2.1 BLOCK DIAGRAM
Figure 2: Module schematic
The N8-LRW module features very high RF performances. Thanks to very low noise level generated by the LNA component,
module’s sensitivity is -142dBm (BW = 125kHz, SF = 12), while most modules available on the market have a sensitivity of
-137dBm.
By using both the RF PA Boost output and the RF Out output of the SX1272, users will have the choice to operate at 20 or
14dBm without over-consumption.
2.2 DIMENSIONS
Module dimensions
Module footprint
Figure 3
All ARM-Nx-xxx modules are footprint compatible and share the same dimensions.
STM32L151CBU6
SX1272
LNA
RF SWITCH
RF FILTER
RF out
RF in
RF out 14dBm
RF PA boost 20dBm
30
18

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Figure 3 shows the ARM-N8-LWR module dimensions. Dimensions are in mm.
The N8-LRW has the same size as other models from ATIM range and keeps the compatibility of all the essential pins. By
choosing the footprint of the N8LRW, you can use any ATIM N8 module.
2.3 PINOUTS
Table 1 below describes pin allocation according to the layout on Figure 2. Some pins are currently reserved for future
development.
Table 1 pin allocation
Pin
Name
I/O
Function
1
AGND
-
Ground (1)
2
ANTENNA
I/O
RF signal
3
AGND
-
Ground (1)
4
GPIO0
O
STA_DO_0
5
GPIO1
O
STA _DO_1
6
AGND
-
Ground (1)
7
GPIO2
I
STA _CPT_0
8
GPIO3
I
STA
9
GPIO4
-
NC
10
GPIO5
-
NC
11
GPIO6
-
NC
12
GPIO7
-
NC
13
GPIO8
I
STA _ADC_0
14
DGND
-
Ground (1)
15
GPIO15
NC
16
GPIO16
NC
17
GPIO17
NC
18
DGND
-
Ground (1)
19
VDD
-
Power supply
20
WAKE-UP
I
Wake-up input
Can be NC if not used
21
GPIO9
I
STA _DI_1
22
GPIO10
I
DL_REC / RTU_ON
23
U1RX
I
RX UART
24
U1TX
O
TX UART
25
GPIO11
-
STA VSensEN
26
GPIO12
I
STA _DI_2
27
nReset
I
Hardware reset, active when set to GND
It is advised to be connected to VDD, can be NC if not used
28
AGND
-
Ground (1)
29
GPIO13
-
NC
30
GPIO14
O
STA _DO_2
31
AGND
-
Ground (1)
32
AGND
-
Ground (1)
STA:Standalone

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2.4 ELECTRICAL CHARACTERISTICS
Following values in table 2 have been measured on pre-series devices, and do not correspond to the series. They will be soon
updated to describe electrical characteristics of the series.
Table 2 : Electrical ratings
Min.
Typ.
Max.
Power Supply (Vdd)
3V
3.3V
3.6V
Consumption (Vdd = 3.3V)
Tx / 14dBm
45 mA
50 mA
56 mA
Tx / 20dBm
-
150
160
Rx
20 mA
22 mA
24 mA
Veille
0.5 µA
0.6 µA
0.9 µA
Input voltage
Gnd
-
0.2 xVdd
Output voltage
0.8 x Vdd
-
Vdd
2.5 LINK INTERFACES
▪UART 2 wires + flow control by RTS/CTS (1200 –230400 bps)
▪SPI Slave (≤2MHz)
▪1 wake up input
▪1 digital output « signalization »
▪1 analog output 12 bits (option)
▪functioning mode:
▪Transparent mode « UART/RF bridge » or « SPI/RF bridge »
▪Repeater mode M2M; M2M/LoRaWAN
▪Standalone mode
▪Configuration mode « AT » local and distant
▪Test modes: Ping-pong, pure carrier, continuous request, RSSI reading
2.6 POWER SUPPLY
The module’s power supply is between 2,7V and 3,6V. To ensure good filtering of power supply, the LC filter must be
positioned as close to the pin VDD as possible.
Figure 4: Power supply filter
GND
Vcc
68pF
100nF
100nH

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2.7 IMPEDANCE OF THE ANTENNA MATCHING
Passive components to be integrated between the antenna and the RF pin of ARM-Nx module depend on the length of the
electronic track, of the dielectric and of the chosen antenna. For a quick implementation, a 68pF serial condenser can be
used. Other components are optional and do not need to be wired.
It is important to keep these components in Pi to be able to modify impedances in case the antenna was not correctly
adapted.
Figure 5: Impedance matching
2.8 FOOTPRINT AND GROUND PLAN
It is recommended to cover the whole surface underneath ARM-Nx modules with a ground plan. This surface must be
varnished to avoid any short circuit. It is advised not to put any vias on this surface nor to use ovarnished vias.
68pF
NC
NC
50ohm line