EWRF Technology US915 LoRaWAN RF Module User Manual

EWRF Technology US915 LoRaWAN RF Module

Product Information

Specifications

• Model: EWRF1022MLA LoRaWAN+wM-bus
• Version: V1.0.1
• Manufacturer: EWRF Technology, Co., LTD
• Date: 2022.01.11
• Frequency Range: 902-928 MHz
• Protocols: LoRaWAN 1.0.3 Class A/C, Wireless M-bus T1/C1
• Interface: UART
• Data Encryption: AES 128
• Compliance: CE RED/FCC 15.247

Product Usage Instructions

The EWRF1022MLA module integrates the LoRaWAN protocol stack (LoRaWAN Specification 1.0.3 Class A/C) and the wM-bus T1/C1 mode. It provides convenient and fast LoRaWAN network access and one-way data communication in wM-bus T1/C1 mode using a UART interface.

• Ultra Low-power SoC chip ASR6601 embedded with one Sub 1G transceiver and one ARM STAR-MC1 MCU
• Supports 902-928 MHz channels
• Easy to use UART interface for communication and configuration
• AT command support for communication and configuration
• Data encryption using AES 128
• Compliance with CE RED/FCC 15.247 requirements

Scope

• This manual applies to firmware version LoRaWAN 1.0.3_wMbus 1.0.2-20220101 and later.

FAQ

• Q: What are the supported protocols of the EWRF1022MLA module?
• A: The module supports LoRaWAN 1.0.3 Class A/C and Wireless  M-bus T1/C1 protocols.
• Q: How can I communicate with the module?
• A: You can communicate with the module using the UART interface and AT commands for configuration and data exchange.
• Q: What is the data encryption method used by the module?
• A: The module uses AES 128 for data encryption.

Document History

2023.4.12

| ****

V1.0.1

| C1 of wM-busmodeadded Specification of module added Typical application circuit added

Fix some errors

 |  |

Introduction

EWRF1022MLA module integrates the LoRaWANprotocol stack (LoRaWAN Specification 1.0.3 Class A/C) and the wM-bus T1/C1 mode. The module uses the UART interface to exchange messages with the user’s equipment, providing convenient and fast LoRaWAN network access, and one-way data communication in wM-bus T1/C1 mode.

Feature

• Ultra Low-power SoCchipASR6601 embeddedwithoneSub 1Gtransceiver and one ARM STAR-MC1 MCU, supporting 902-928 MHz channels
• Embedded LoRaWAN (1.0.3) Class A/C and Wireless M-bus T1/C1 protocols
• Easy to use UART interface for communication and configuration
• AT command for communication and configuration
• Data encryption AES 128
• Conforms with CE RED/FCC 15.247 requirements

Scope
This manual applies to firmware version: LoRaWAN1.0.3_wMbus1.0.2-20220101 and later.

Working Mechanism

Modes
The module has two working modes: transparent transmission and command.

1. The command mode uses AT commands to configure parameters, read status send data, etc.. In the command mode, when sending a parameter configuration or a status reading command, the user needs to wait for the module to return “OK” or “ERROR” before proceeding with the next command, otherwise the command may be invalid. When switching from transparent transmission mode to the command mode, the instruction (0x00 0x00 0x00) needs to be input and does not include the terminator “\r\n”.
2. The transparent transmission mode is used to send and receive application data. In this mode, there are two kinds of communication, namely the LoRaWAN communication and the wM-bus communication. The LoRaWAN communication requires the module to join the network before it can access the LoRaWAN data services. The two communications can be switched from the AT command mode by inputting the “AT+SWTMD”.

Power-on/Resetinitialization
When the module is powered on/reset (hardware or software reset), it will be initialized. At this time, the module is in command mode, and the module can be operated through AT commands.

Parameters stored in non-volatile memory
If the user wants to store the parameters after power-off, the “AT+SAVE commands need to be executed to set the LoRaWAN orwM-bus parameters in the non-volatile memory. After the module is powered on/reset, the saved parameters will be read from the storage space. If the user doesn’t execute the “AT+SAVE” commands, the set parameters will be lost after power-off/ reset.

UART communication
The UART communication flow between the module and the user MCU includes three message types: command, response, and event. The command and response messages are used for parameter configuration and other operations, and the event messages are used for uplink/downlink data communication, as shown in Table 2-1.

Table 2-1 UART Communication Messages Type

module
response| module–> user| Module responses to the user MCU
event| Module <–>user| data communication| Asynchronous events that occur at any time: The user sends uplink data to the module;

The module sends downlink data to the user MCU;

The module sends the failure report, etc.

Specification

 | Parts No.

Items

|

EWRF 1022MLA

---|---|---

Electronics

| Operating voltage| 2.0-3.7v
TX current| <125 mA（@20dbm）
RX current| <10 mA
Sleep current| <1.5μ A
Operation current| < 20 μ A（@T1，30s TX period）

RF

| Frequency| US 902-928 Mhz(LoRaWAN)/868.95Mhz(T1,C1)
Modulation| LoRa/FSK
TX power| <21dBm

Data rate

| LoRaWAN:250-5470bps

T-mode: 100 kbps

C-mode: 100 kbps

RX sensitivity| -104 dBm（T/C-mode）
Ant.     impedance| 50 Ω

Security

| Data filter| CRC
Data encryption| AES 128

General

| Interface| Uart (TTL)
Uart Format| 8 N1 without parity
Uart baud| 9600bps
Operating temperature| -30℃ ～80℃
Operating humidity| 10～90% without condensation
Communication range| >200m(T1@868Mhz/14dbm/100Kbps,LOS)

Mechanics

Pin Description

• Pin descriptions are shown in

Table 2-2： Table 2-2 Pin Descriptions of the Module

TypicalApplicationCircuit

Note: When using Transparent Transmission for data transmission and reception, it is recommended to connect the BUSY and STAT pins of the module to detect the status of the module. When using the AT+LSEND command to transmit and receive data in LoRaWAN, the BUSY and STAT pins fail and can be ignored.

Command Mode

The command mode is used for module parameter configuration, status reading, etc. Users can access the module by sending AT commands through the UART, to perform operations such as reading or writing configuration or query of status from registers. After the module is powered on/reset, it enters the command mode by default. In this case, the user can perform AT command operations directly. In command mode, the format of UARTport is fixed as: baud rate 9600bps, no parity, 8 bits data, 1 stop bit. The user sends an AT command to the module, the module parses the command, and returns a command response immediately, indicating the execution result of the command. If the module does not respond for a long time, it means the module status is abnormal.

AT Command Format
AT commands are used in uppercase ASCII format, starting with “AT” and ending with a carriage return and line feed (ie “\r\n”). The maximum length of the command string is 255 characters (including “\r\n”) . AT commands can be subdivided into four types, as shown in Table 3-1。

Table 3-1 AT Command Type

Type| Format| D e s c r i p t i on
---|---|---
query command| AT+?| return the current value of the parameter
set command| AT+=<…>| set user-defined parameter values
execute command| AT+| execute the internal program of the module without parameters
special command| 0x00 0x00 0x00| exit from the transparent transmission mode to AT command mode

Notes: Special command0x00 0x00 0x00 is only valid in transparent transmission mode, and does not contain the terminator “\r\n”.

Table 3-2 Error codes of AT command

LoRaWAN Activation

According to the LoRaWAN specification, the necessary parameter configuration is required before using the module. There are two activation modes to choose from (OTAA activation mode is mainly used at present). The parameters required for each mode are different, as shown in Table 3-2.

Table 3-2Activation Mode and Required Parameters

Over the Air Activation (OTAA)

| The module obtains the network security  key  by  joining  the

network

|

DevEui、AppEui、AppKey， OTAA activation

Activation by personalization (ABP)

| The module has saved the network session key and application encryption key locally and  can  join  the  specified

LoRaWANserver

|

DevAddr、NwkSkey、AppSkey,  ABP activation

Transparent Transmission

• A transparent transmission mode is used to send and receive application data.
• In the command mode, use “AT + SWTMD” to select LoRaWAN communication or wM-bus communication .
• In LoRaWAN, The module does not work until the module successfully join the network.

Data Communication Timing

Figure 4-1 describes in detail the flow of a complete data interaction after the module successfully joins the network when the user operates the module.

1. The user waits for the module to be ready, that is, waits for BUSY to be low. When the module is ready, the user sends serial port data to the module.
2. Wait for the serial port framing timeout (the data size transmitted by the user at one time is less than the maximum data packet limit of LoRaWAN or wM-bus), that is, wait for the completion of user data transmission from UART.
3. When the module receives a frame of the user’s data, it will pull the BUSY pin high, indicating that the module is busy, and pull up the STAT pin at the same time.
4. The module transmits data (uplink), and BUSY remains high. In LoRaWAN mode, if the Confirmed frame fails to be transmitted, the module will automatically retransmit.
5. In LoRaWAN mode, if the current frame is Confirmed or the server has downlink data, the module will receive the data.
6. The module completes data (uplink and downlink) processing, the BUSY pin is pulled low. If the communication data is abnormal, the STAT pin will remain high for indication. The STAT pin will not return to low until new data is coming from UART or the module switches to the command mode (inputting 0x00 0x00 0x00). If there is no abnormality, the STAT pin also becomes low.
7. In LoRaWAN, if the server has downlink data, the module first completes data analysis and then sends it to the user through the UART after Td (default 10ms) time.

Note: According to the duty cycle requirements in CE RED, in LoRaWAN communication the next transmission interval is approximately 100 times the duration of the communication in the air. Otherwise, the LoRaWAN program may be forcibly stop sending user data.

The UART packet format in wM-bus
In wM-bus, the user’s device needs to send the packet to the UART of the module in the following format:

• L: Packet length(excluding itself)
• C: Packet type, for example, SND-NR is 0x44
• CI: Packet communication ID, for example, the short header of SND-NR is 0x7A
• DATA: User application data, which is formed according to the data format of M-BUS, includes an 8-bit BCD meter readout, collection time in a certain format (year, month, day, hour), error flags, etc.

AT Command Set

• The AT command set is classified into the Basic, LoRaWAN configuration, and wM-bus configuration.

Basic commands

• The Basic AT commands are mainly to restart and configure UART and other application parameters that are not related to the network operation, as shown in Table 5-1。

Table5-1 Basic Commands

AT—AT Test

Write & Response

| ****

AT

| OK

or

+ERROR:

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 | ****