EBYTE EWM32M-xxxT20S AT Directive 20dBm Small Form Factor LoRa Wireless Module User Manual

EWM32M-xxxT20S AT Directive 20dBm Small Form Factor LoRa Wireless Module

“

Specifications:

• Model: EWM32M-xxxT20S
• Transmit Power: 20dBm
• Communication Technology: LoRa
• Frequency Bands: 433MHz and 900MHz
• Interface: UART
• Output: TTL level
• Operating Voltage: 3.3V
• Communication Distance: Up to 5km
• Power Consumption in Hibernation: 3uA

Product Usage Instructions:

1. Brief Introduction:

The EWM32M-xxxT20S series is an ultra-small size, low-cost
wireless serial module that is fully compatible with LoRa
communication technology. It operates at a transmit power of 20dBm
in the 433MHz and 900MHz bands. The module offers longer
communication distance, strong anti-interference ability, and
strong confidentiality.

2. Features:

• New generation LoRa spread spectrum modulation technology for
  longer communication distance and anti-interference ability
• Supports firmware upgrade via serial port for convenient
  updates
• AT command support for ease of use
• Forward error correction (FEC) for improved communication
  stability
• Supports global license-free ISM bands
• Ability to set user communication key for enhanced data
  confidentiality
• Listen-Before-Talk (LBT) function for better communication
  success rate in harsh environments
• Wireless parameter configuration for remote setup
• Wake-on-Air feature for ultra-low power consumption in
  battery-powered applications
• Supports various transmission modes including fixed-point and
  broadcast transmission
• Deep hibernation mode with minimal power consumption

3. Usage Guidelines:

1. Power Supply: Ensure the module is powered
   with a stable 3.3V source.
2. Communication Setup: Connect the module to the
   desired device using UART interface.
3. Firmware Upgrade: Use the serial port to
   upgrade the firmware as needed.
4. AT Commands: Utilize AT commands for
   configuring and controlling the module.
5. Data Confidentiality: Set a user communication
   key for enhanced data security.
6. Hibernation Mode: Activate deep hibernation
   mode when low power consumption is required.

Frequently Asked Questions (FAQ):

Q: Can the module work with both 433MHz and 900MHz frequency
bands?

A: Yes, the EWM32M-xxxT20S module is designed to operate in both
the 433MHz and 900MHz bands.

Q: How far can the module communicate under ideal
conditions?

A: The communication distance of the module can reach up to 5km
under ideal conditions.

Q: Does the module retain parameters after power down?

A: Yes, parameters are saved when the module is powered down,
and it will operate according to the set parameters upon power
up.

“`

EWM32M-xxxT20S User Manual
AT Directive 20dBm Small Form Factor LoRa Wireless Module

EWM32M-xxxT20S User Manual
Disclaimer
EBYTE reserves all rights to this document and the information contained herein. Products, names, logos and designs described herein may in whole or in part be subject to intellectual property rights. Reproduction, use, modification or disclosure to third parties of this document or any part thereof without the express permission of EBYTE is strictly prohibited.
The information contained herein is provided “as is” and EBYTE assumes no liability for the use of the information. No warranty, either express or implied, is given, including but not limited, with respect to the accuracy, correctness, reliability and fitness for a particular purpose of the information. This document may be revised by EBYTE at any time. For most recent documents, visit www.cdebyte.com.

Copyright ©2012­2025Chengdu Ebyte Electronic Technology Co.,Ltd.

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Contents

EWM32M-xxxT20S User Manual

EWM32M-xxxT20S User Manual………………………………………………………………………………………………………………………..0 1 Introduction ………………………………………………………………………………………………………………………………………………………… 4
1.1 Brief Introduction ………………………………………………………………………………………………………………………4 1.2 Features ……………………………………………………………………………………………………………………………………4 1.3 Application ……………………………………………………………………………………………………………………………….5 2 Specification ………………………………………………………………………………………………………………………………………………………. 5 2.1 RF parameters……………………………………………………………………………………………………………………………5 2.2 Electrical parameters ………………………………………………………………………………………………………………….6 2.3 Hardware parameters………………………………………………………………………………………………………………….6 3 Mechanical Dimensions and Pin Definitions ……………………………………………………………………………………………………. 7 3.1 EWM32M-433/900T20S Mechanical Dimensions and Pin Definitions …………………………………………….7 4 Recommended Connectivity Charts ………………………………………………………………………………………………………………….. 9 5 Functions in detail …………………………………………………………………………………………………………………………………………… 10 5.1 Fired at a fixed point…………………………………………………………………………………………………………………10 5.2 Broadcast emission…………………………………………………………………………………………………………………..10 5.3 Broadcast address …………………………………………………………………………………………………………………….11 5.4 Listening address ……………………………………………………………………………………………………………………..11 5.5 Module reset ……………………………………………………………………………………………………………………………11 5.6 AUX in detail ………………………………………………………………………………………………………………………….11 6 Operating mode ……………………………………………………………………………………………………………………………………………….. 13 6.1 Mode switching precautions………………………………………………………………………………………………………14 6.2 General mode (mode 0) …………………………………………………………………………………………………………….14 6.3 WOR mode (mode 1) ……………………………………………………………………………………………………………….15 6.4 Power saving mode (mode 2) …………………………………………………………………………………………………….15 6.5 Deep sleep mode (mode 3) ………………………………………………………………………………………………………..15 7 Register read/write control ……………………………………………………………………………………………………………………………… 16 7.1 Command Introduction……………………………………………………………………………………………………………..16 7.2 Reading of operating parameters………………………………………………………………………………………………..16 7.3 Version number reading ……………………………………………………………………………………………………………16

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EWM32M-xxxT20S User Manual
7.4 Reset command ……………………………………………………………………………………………………………………….17 7.5 EWM32M-xxxT20S Register Description…………………………………………………………………………………..17 7.6 Factory Default Parameter…………………………………………………………………………………………………………18 8 AT command …………………………………………………………………………………………………………………………………………………… 19 8.1 AT command table …………………………………………………………………………………………………………………..19 8.2 AT Parameter Analysis……………………………………………………………………………………………………………..21 8.3 Serial Port Upgrade Firmware Notes…………………………………………………………………………………………..21 9 Configuration instructions for the host computer…………………………………………………………………………………………… 22 10 Hardware design ……………………………………………………………………………………………………………………………………………. 22 11 Common problems ………………………………………………………………………………………………………………………………………… 23 11.1 Unsatisfactory transmission distance…………………………………………………………………………………………23 11.2 Modules are fragile…………………………………………………………………………………………………………………24 11.3 BER is too high ……………………………………………………………………………………………………………………..24 11.4 Antenna Selection…………………………………………………………………………………………………………………..24 12 Welding instructions ……………………………………………………………………………………………………………………………………… 25 12.1 Reflow temperature ………………………………………………………………………………………………………………..25 12.2 Reflow temperature ………………………………………………………………………………………………………………..25 13 Related Models ……………………………………………………………………………………………………………………………………………… 26 14 Antenna Guide ………………………………………………………………………………………………………………………………………………. 26 14.1 Antenna Recommendation ………………………………………………………………………………………………………26 15 Batch packing method …………………………………………………………………………………………………………………………………… 28 Revision history………………………………………………………………………………………………………………………………………………….. 28 About us ……………………………………………………………………………………………………………………………………………………………… 29

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1 Introduction

EWM32M-xxxT20S User Manual

1.1 Brief Introduction
EWM32M-xxxT20S series (UART) is an ultra-small size, low-cost wireless serial module (UART), and the E32 is fully compatible with the interoperability of the LORA communication technology, its transmit power of 20dBm, with a variety of transmission modes, working in the 433-band and the 900-band, TTL level output, compatible with the 3.3V IO port voltage.
EWM32M-xxxT20S has the advantages of longer communication distance, strong anti-interference ability, and strong confidentiality. The factory default air rate is 2.4kbps, and the transmit power is 20dBm, which improves the communication stability and extends the communication distance; the two modules in the figure below have the same power and different frequency bands.

EWM32M-433T20S

EWM32M-900T20S

1.2 Features

Adopts the new generation of LoRa spread spectrum modulation technology, which brings longer communication
distance and stronger anti-interference ability; Supports serial port to upgrade firmware, which makes updating firmware more convenient; Supports AT command, which is more convenient to use; Supports FEC forward error correction, improving communication stability; Supports global license-free ISM 433MHz band or 868/915MHz EU common band; Supports users to set their own communication key and it cannot be read, which greatly improves the confidentiality
of user data; Supports LBT function to listen to the channel environmental noise before sending, which can greatly improve the
success rate of the module’s communication in harsh environments; Supports wireless parameter configuration, sending command packets wirelessly to remotely configure or read
wireless module parameters; Supports Wake-on-Air, i.e., ultra-low power consumption function for battery-powered application solutions; Supports fixed-point transmission, broadcast transmission, and channel listening; Supports deep hibernation, the whole power consumption in this mode is about 3uA; Communication distance is up to 5km under ideal conditions; Parameters are saved when power down, and the module will work according to the set parameters after power up
again;

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EWM32M-xxxT20S User Manual High-efficiency watchdog design, once an exception occurs, the module will be in automatic restart, and can continue
to continue to work in accordance with the previous parameter settings; Supports data transfer rate of 2.4K to 19.2Kbps; Supports 2.7~5.5V power supply, and any power supply greater than 5V can ensure the best performance; Industrial-grade standard design, support -40 ~ +85 for long time use; Module power can be up to 100mW (20dBm), transmission farther and more stable.
1.3 Application
Home security alarms and remote keyless entry; Smart home as well as industrial sensors and more; Wireless alarm security systems; Building automation solutions; Wireless industrial grade remote controls; Healthcare products; Advanced Meter Reading Architecture (AMI).
2 Specification

2.1 RF parameters

RF unit
parameters

Maximum Transmit dBm
Power Receiving
dBm Sensitivity

Reference M
Distance

Operating Frequency
Band

MHz MHz

Minimum value –
123
410 862

Performances Typical value
20 124 5K 433 900

Maximum values
–

Remark –

125

Air rate of 2.4kbps

Clear and open, antenna gain 5dBi,

–

antenna height 2.5 meters, air rate

2.4kbps.

441

Applicable to EWM32M-433T20S.

930

Applicable to EWM32M-900T20S.

Air Rate

bps

Blocking dBm
power

2.4K –

2.4K -10

19.2K –

User programmable control Less probability of burnout in close
proximity

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EWM32M-xxxT20S User Manual

2.2 Electrical parameters

UNI Electrical parameters
T

operating voltage

V

communications level

V

Transmit

Current

mA

power consump Receive
mA tion Current

Sleep

uA

Current

operating temperature

model number

EWM32M-

EWM32M-

433T20S

900T20S

2.75.5

2.75.5

3.3V 110

3.3V Transient power
consumption @22dBm

Remark
Output power is guaranteed at 3.3V, 5V typical, above 5.5V permanently burns out the module.
Risk of burn-in using 5V TTL
Instantaneous power consumption @22dBm

8

3

Software shutdown

-40+85

Software shutdown Industrial Grade Design

2.3 Hardware parameters

Hardware parameters
Modulation mode
Interface Mode Communicat ion Interface
Transmit length
Package Cache Capacity Antenna

Model Nnumber

EWM32M-433T20S

EWM32M-900T20S

LoRa

1.27mm stamp hole

UART serial port

58 Btye
SMD 512Btye IPEX-1/Stamp Hole

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Remark
New generation of LoRa modulation technology
TTL level Maximum capacity of a single package, automatically divided into
packages after exceeding it –
Equivalent impedance approx. 50
6

Interface Dimension Net Weight

14*20mm 2.0g

EWM32M-xxxT20S User Manual
±0.2mm ±0.1g

3 Mechanical Dimensions and Pin Definitions 3.1 EWM32M-433/900T20S Mechanical Dimensions and Pin Definitions

Pin No 1 2 3 4 5

Name GND NC GND GND TX_EN

Pin Direction –
Output

Pin Usage Module Ground Empty pin (not open for use, no need for user concern) Module Ground Module Ground Used in conjunction with RX_EN to control external PA; left blank if not used

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EWM32M-xxxT20S User Manual

6

RX_EN

Output

Used in conjunction with TX_EN to control external PA; left blank if

not used

7

CLK

Input/Output SWCLK Clock pin for program loading (dangling, no need to be

connected by the user)

8

DIO

Input/Output SWDIO Data pin for program loading (dangling, no need to be

connected by the user)

9

NC

–

Empty foot (not open for use, no need for users to care)

10

NC

–

Empty foot (not open for use, users do not need to care)

11

NC

–

Empty feet (not open for use, users do not need to care)

12

NC

–

Empty foot (not open to use, users do not need to care)

13

GND

–

Module Ground

14

VCC

–

Module power positive reference, voltage range: 2.7 to 5.5V DC

15

TXD

OUTPUT

TTL serial output, connected to external RXD output pin;

16

RXD

Input

TTL serial input, connected to external TXD output pin;

17

M1

Input

TTL serial input, connected to the external TXD output pin; and M0,

determines the module’s four operating modes (can not be suspended, if

not used can be grounded)

18

M0

Input

In conjunction with M1, determines the 4 modes of operation for the

module (not dangling, can be grounded if not in use)

Used to indicate the working status of the module; the user wakes up

19

AUX

Output

the external MCU and outputs a low level during power-on self-test

initialization; (can be suspended)

20

NC

-Input

Empty pin (not open for use, no need for user to care)

21

RESET

Input

Module reset pin, low level reset.

22

GND

–

Module ground

23 ANT

Antenna interface (high frequency signal output, 50 ohm characteristic –
impedance)

24

GND

–

Module Ground

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4 Recommended Connectivity Charts

EWM32M-xxxT20S User Manual

No

Brief connection description between the module and the microcontroller (the above figure takes the STM8L microcontroller as an example)

1

The wireless serial module is TTL level, please connect with TTL level MCU.

2

For some 5V MCUs, it may be necessary to add 4 to 10K pull-up resistors to the TXD and AUX pins of the module.

3

It is recommended to reserve 1M pull-up resistor at the M0/M1 interface.

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5 Functions in detail 5.1 Fired at a fixed point

EWM32M-xxxT20S User Manual

5.2 Broadcast emission

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5.3 Broadcast address

EWM32M-xxxT20S User Manual

Example: set module A address to 0xFFFF and channel to 0x04. When module A is used as a transmitter (same mode, transparent transmission method), all receiving modules under
channel 0x04 can receive the data for the purpose of broadcasting.

5.4 Listening address
Example: set module A address to 0xFFFF and channel to 0x04. When module A is used as a receive, it can receive all the data under channel 0x04 to achieve the purpose of
listening.

5.5 Module reset
After the module is powered on, AUX will immediately output a low level, and carry out hardware self-test, as well as set up the working mode according to user parameters; During this process, AUX will keep low level, and when finished, AUX will output high level, and start to work normally according to the working mode combined by M1 and M0; Therefore, the user needs to wait for the rising edge of AUX as the starting point of normal operation of the module.

5.6 AUX in detail

AUX is used for wireless transceiver buffer indication and self-test indication. It indicates whether the module has data that has not yet been transmitted out through the wireless, or whether the
wireless data that has already been received has not yet been sent out in full through the serial port, or whether the module is in the process of initializing the self-test.

5.6.1 Serial data output indication

is used for waking up an external MCU in hibernation;

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EWM32M-xxxT20S User Manual
5.6.2 Radio transmission indication
Buffer Empty: the data in the internal 512 byte buffer are written to the wireless chip (automatic packetization). When AUX=1 when the user continuously initiates less than 512 bytes of data, will not overflow. When AUX=0 when
the buffer is not empty: the internal 512-byte buffer data, not yet all written to the wireless chip and open the launch, at this time the module may be waiting for the end of the user’s data timeout, or are wireless sub-packet launch. [Note]: AUX=1 does not mean that all the serial data of the module have been launched through the wireless, or the last packet of data is being launched.

5.6.3 Module in the process of being configured
only when resetting and exiting hibernation mode;

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EWM32M-xxxT20S User Manual

5.6.4 Caution

No

AUX Notes

For function 1 and function 2 above, the output low level is prioritized, i.e.: when any of the output low level

1 conditions are satisfied, the AUX outputs a low level;

When all low level conditions are not satisfied, AUX outputs high level.

When AUX outputs low level, it indicates that the module is busy, and no working mode detection will be 2 performed at this time;
When the module AUX output high level within 1ms, will complete the mode switching work.

After the user switches to a new operating mode, at least 2ms after the rising edge of AUX is required for the 3 module to actually enter that mode;
If AUX stays high, then the mode switching will take effect immediately.

4

The module resets the user parameters when the user enters from mode 3 (sleep mode) or during a reset, during which the AUX output goes low.

Due to the characteristics of LoRa modulation, the information transmission delay is much longer than FSK,

5

such as in 2.4kbps air speed, 100 bytes of transmission delay is about 1.5 seconds, it is recommended that customers do not carry out the transmission of large amounts of data at low air speeds, so as to avoid data loss

due to the accumulation of data caused by the communication anomaly.

6 Operating mode

The module has four operating modes, which are set by pins M1 and M0; details are shown in the table below:

Mode03

M1

M0

Mode Introduction

Remark

0 General Mode

0

0 Serial open, wireless open, transparent transmission

The receiver must be mode 0, 1

1 Wake-up mode

0

1

Serial port open, wireless open; The only difference with mode 0: before the packet is transmitted, the wake-up code is automatically increased so as to wake up the receiver working in mode 2

Receiver can be mode 0 Receiver can be mode 1 Receiver can be mode 2

2 Power saving mode

1

0

Serial port reception is off, wireless is in Wake-on-Air mode, and when wireless data is received, the serial port is opened to send out the data.

Transmitter must be in mode 1

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EWM32M-xxxT20S User Manual

3 Sleep mode

1

1

Module goes to sleep and can receive parameter setting Cannot transmit in this

commands

mode

6.1 Mode switching precautions

No

Remark

Users can combine M1 and M0 with high and low levels to determine the module working mode. The 2

GPIOs of MCU can be used to control the mode switching; When changing M1, M0: If the module is idle, it can start working according to the new mode after 1ms; If the module has serial data that has not yet finished transmitting through wireless, it can enter the new 1
working mode only after the transmitting is finished; If the module receives wireless data and sends out the data through the serial port, it needs to finish sending

out before it can enter the new working mode; So the mode switching can only be effective when AUX outputs 1, otherwise the switching will be delayed.

For example, if the user inputs a large amount of data continuously and switches modes at the same time,

the switching mode operation is invalid at this time; the module will process all the user data before

2

detecting a new mode;

So the general recommendation is: detect the output state of AUX pin, wait for 2ms after the output high

level before switching.

When the module is switched to hibernate mode from other modes, if there is data that has not been processed; The module will process this data (both receive and transmit) before entering sleep mode. This feature can

be used for fast hibernation to save power consumption; for example: the transmitter module works in mode

0, the user initiates the serial data “12345”, and then does not have to wait for the AUX pin to be idle (high),

3

it can be directly switched to hibernation mode and the user’s main MCU is immediately hibernated, and the

module automatically sends all the user’s data wirelessly. After sending out all the user data through wireless,

the module will automatically enter hibernation within 1ms; Thus saving MCU’s working time and reducing power consumption.

Similarly, any mode switching can utilize this feature, the module will automatically enter a new mode within

1ms after processing the current mode event; thus saving the user the work of querying the AUX, and can

achieve the purpose of fast switching; 4 For example, switching from transmitter mode to receiver mode; the user MCU can also enter hibernation

before mode switching, and use the external interrupt function to obtain the AUX change, so as to carry out

mode switching.

This operation method is very flexible and efficient, completely designed in accordance with the user’s MCU

5

operating convenience, and can minimize the workload of the entire system, improve system efficiency and

reduce power consumption.

6.2 General mode (mode 0)

Type

When M0 = 0 and M1 = 0, the module operates in mode 0

transmitter

Module receives user data from the serial port, the module transmits wireless data packet length of 58 bytes, when the amount of data input by the user reaches 58 bytes, the module will start the wireless transmission, at this time, the user can continue to input the data that need to be transmitted; when the user needs to transmit bytes less than 58 bytes, the module waits for the 3 bytes of time, if there is no user data continue to input, it is considered to be the termination of the data, at this time, the module will be all the data packets

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receiver

EWM32M-xxxT20S User Manual
through the wireless sent; when the module receives the first user data, will AUX output low level, when the module puts all the data into the RF chip and starts to transmit, AUX output high level;
The module always turns on the wireless receive function and can receive packets sent from mode 0 and mode 1; After receiving the packet, the module AUX outputs a low level, and after a delay of 5ms, it starts to send out the wireless data through the TXD pin of the serial port, and after all the wireless data are output through the serial port, the module outputs the AUX to a high level.

6.3 WOR mode (mode 1)

Type transmitter
receiver

When M0 = 1 and M1 = 0, the module operates in mode 1
The conditions for the module to start packet transmitting and the AUX function are equivalent to mode 0; the only difference is: the module will automatically add a wake-up code before each packet, and the length of the wake-up code depends on the wake-up time set in the user’s parameter; the wake-up code is intended to be used to wake up the receiver module working in mode 2; so the data transmitted in mode 1 can be received by modes 0, 1 and 2.
Equivalent to mode 0.

6.4 Power saving mode (mode 2)

Type transmitter
receiver

When M0 = 0 and M1 = 1, the module operates in mode 2
The module is in hibernation state, the serial port is closed and cannot receive the serial data from the external MCU, so this mode does not have the wireless transmitting function.
In Mode 2, the transmitter is required to work in Mode 1; listen to the wake-up code at regular intervals, once a valid wake-up code is received, the module will continue to be in the receiving state and wait for the whole valid packet to be received; then AUX outputs a low level, and after a delay of 5ms, it opens the serial port and sends out the received wireless data through TXD, and after that, it outputs a high level from AUX; the module continues to enter the “sleep – listen” operating state (polling); by setting different wake-up times, the module has different receiving response delays (maximum 2s) and average power consumption (minimum 30u The wireless module continues to enter the “sleep-listening” working state (polling); by setting different wake-up times, the module has different reception response delays (up to 2s) and average power consumption (minimum 30uA); the user needs to achieve a balance between the communication delay time and the average power consumption.

6.5 Deep sleep mode (mode 3)

Type

When M0 = 1 and M1 = 1, the module operates in mode 3

transmitter Cannot transmit wireless data.

receiver configuration
note

Cannot receive wireless data.
The hibernation mode can be used for module parameter setting, using the serial port 9600, 8N1, to set the module operating parameters through a specific command format.
When entering from hibernation mode to other modes, the module will reconfigure the parameters, and during the configuration process, AUX stays low; when finished, it outputs a high level, so it is recommended that the

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user detects the rising edge of AUX.

EWM32M-xxxT20S User Manual

7 Register read/write control

7.1 Command Introduction

The list of supported commands in hibernation mode (Mode 3: M0=1, M1=1) is as follows (only 9600, 8N1 format is

supported at the time of setting):

No

Command format

Explanation

1

C0+Operating Send C0 + 5 bytes of operating parameters in hexadecimal format, totaling 6 parameters bytes, must be sent continuously (power-down saved)

2

C1+C1+C1

Sending three C1 in hexadecimal format, the module returns the saved parameters, which must be sent continuously.

3

C2+Operating Sending C2+5 bytes of operating parameters in hexadecimal format, totaling 6 parameters bytes, must be sent continuously (power down is not saved)

4

C3+C3+C3

Send three C3 in hexadecimal format, the module returns the version information, must be sent continuously.

5

C4+C4+C4

Send three C4 in hexadecimal format, the module will generate a reset, must be sent continuously.

7.2 Reading of operating parameters

command format C1+C1+C1

explanation
In hibernation mode (M0=1, M1=1), issue the command (in HEX format): C1 C1 C1, to the module serial port. The module will return the current configuration parameters, e.g., C0 00 00 1A 06 44.

7.3 Version number reading

command format C3+C3+C3

explanation
In sleep mode (M0=1, M1=1), send a command (in HEX format) to the module serial port: C3 C3 C3, the The module will return the current configuration parameters, for example: C3 32 XX YY; C3 is the command header, 32 represents the product model, XX represents the version number, YY represents the interface format + module maximum power value (hexadecimal). 0x10 for TTL interface, 0x40 for RS232, 0x80 for RS485

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7.4 Reset command

EWM32M-xxxT20S User Manual

command format C4+C4+C4

explanation
In hibernation mode (M0=1, M1=1), send a command (in HEX format) to the module serial port: C4 C4 C4, the The module will generate a reset; During the reset process, the module performs self-test and AUX outputs a low level; after the reset is completed, AUX outputs a high level and the module starts to work normally; At this time, mode switching or initiating the next command can be performed.

7.5 EWM32M-xxxT20S Register Description

Name

Description

0

HEAD

Fixed 0xC0 or 0xC2, indicating that this frame data is a control command

1

ADDH Module address high byte (default 00H)

2

ADDL Module address low byte (default 00H)

7

6 Serial port parity bit

0

0 8N1 (default)

0

1 8O1

1

0 8E1

1

1 8N1 (00 equivalent)

5

4

3 TTL serial port ratebps

0

0

0 The serial port baud rate is 1200

0

0

1 The serial port baud rate is 2400

0

1

0 The serial port baud rate is 4800

0

1

1

The serial port baud rate is 9600 default

1

0

0 The serial port baud rate is 19200

3

SPED

1

0

1 The serial port baud rate is 38400

1

1

0 The serial port baud rate is 57600

1

1

1 The serial port baud rate is 115200

2

1

0 Universal Radio Air Ratebps

0

0

0 Airspeed 2.4k

0

0

1 Airspeed 2.4k

0

1

0 Airspeed 2.4kdefault

0

1

1 Airspeed 4.8k

1

0

0 Airspeed 9.6k

1

0

1 Airspeed 19.2k

1

1

0 Airspeed 19.2k

1

1

1 Airspeed 19.2k

General Model

4

CHAN

7

6

5 Retain unused

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Remark Must be 0xC0 or C2 C0: The set parameters are saved by powerdown. C2: The set parameters will not be saved by power-down. 00H-FFH 00H-FFH
Serial port modes can be different on both sides of the communication
The baud rate of both sides can be different The serial port baud rate is independent of the wireless transmission parameters and does not affect the wireless transceiver characteristics.
The lower the air rate, the longer the distance, the stronger the anti-interference performance, and the longer the sending time. The airborne wireless transmission rate must be the same for both sides of the communication.
Write 0 17

EWM32M-xxxT20S User Manual

communication channel

4 – 0, corresponding to (410MHz + CHAN * 1MHz), default 17H (433MHz) (for 400 band) 4 – 0, corresponds to (862MHz + CHAN * 1MHz), default

00H-1FH, corresponding to 410441MHz 00H-45H, corresponding to 862-930MHz

06H (868MHz) (applicable to 900 band)

7 Fixed-point transmit enable bit (MODBUS-like) 0 Transparent transmission mode

When it is 1, the first 3 bytes of each user data frame are used as high and low address and channel. When transmitting, the

1 Fixed-point transmission mode

module changes its own address and channel, and when finished, restores the

original settings.

6 IO drive mode (default 1)

This bit is used to enable the module’s

1 TXD, AUX push-pull outputs, RXD pull-up inputs internal pull-up resistor. The open drain method level adaptation is more robust and

0 TXD, AUX open output, RXD open input

may require an external pull-up resistor in some cases.

5

4

3 Wireless Wake-Up Time

Both transceiver modules work in mode 0.

0

0

0

0

1

5

OPTIO

1

N

1

0

0 250msdefault

0

1 500ms

1

0 750ms

1

1 1000ms

0

0 1250ms

0

1 1500ms

1

0 1750ms

This delay time is invalid and can be any value; The transmitter works in mode 1 and will continuously transmit the wake-up code for the corresponding time; The receiver works in mode 2, this time is the listening interval time (wireless wakeup) of the receiver, and can only receive

1

1

1 2000ms

data from the transmitter working in mode 1.

2 FEC Switch 0 Turn off FEC error correction

When FEC is turned off, the actual data transmission rate is increased, but the antiinterference ability is weakened, and the

distance is slightly closer, so please choose

1 Turn on FEC error correction (default)

according to the actual application; Both sides of communication must be on or

off.

1

0 Transmit power (approximate)

0

0 20dBmdefault

0

1 17dBm

1

0 14dBm

The external power supply must provide more than 250mA of current output capability and ensure that the power supply ripple is less than 100mV;

1

1 10dBm

It is not recommended to use lower power transmission, its power utilization

efficiency is not high.

Example (Meaning of the byte “SPED” in serial number 3):

Binary bits of this byte

7

6

5

4

3

2

1

0

Specific value (user-configurable)

0

0

0

1

1

0

1

0

Representation

Serial port parity bit 8N1

Serial port baud rate of 9600

Air rate of 2.4k

Corresponding hexadecimal

1

A

7.6 Factory Default Parameter

Model number

Factory default parameter value: C0 00 09 00 00 00 1A 00 17 03 00 00

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18

Module Model
EWM32M433T20S
EWM32M900T20S

frequency
433.125MH z
868.125MH z

Address 0x0000 0x0000

channel 0x17 0x12

airspeed 2.4kbps 2.4kbps

EWM32M-xxxT20S User Manual

baud

Serial Port transmissio

Format

n power

9600

8N1

20dbm

9600

8N1

20dbm

8 AT command

Using AT instructions for parameter configuration or querying needs to be done in the configuration mode; AT instructions are used in the configuration mode. AT instructions are divided into three categories in total: command
instructions, setup instructions and query instructions; Users can pass “AT+HELP=?” Query to the AT instruction set supported by the module, the baud rate adopted by AT
instruction is 9600 8N1; Will be limited when the input parameters exceed the range, please do not let the parameters exceed the range to avoid
unknown situation.

8.1 AT command table

Command instruction AT+IAP (use with caution, see this article 8.3 Notes on Upgrading Firmware on Serial Ports for details) AT+RESET AT+DEFAULT

Description
Entering IAP upgrade mode
Device reboot Configuration parameters are restored to default and the device reboots

Example
AT+IAP
AT+RESET AT+DEFAULT

Example Description
Enter IAP upgrade mode
Reboot the device Configuration parameters are restored to default

Setup command AT+UART=baud,parity
AT+RATE=rate AT+WOR=role AT+POWER=power AT+TRANS=mode

Description Setting the Baud Rate and Checksum Setting the Air Rate Set WOR role and period Set Transmit Power Setting the Transmit Mode

Example AT+UART=3,0
AT+RATE=7 AT+WOR=0 AT+POWER=0 AT+TRANS=1

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Example Description Set baud rate to 9600, 8N1
Set the air rate to 19.2K Set to WOR receive Set the transmit power to 30dBm Set to fixed point mode
19

AT+LBT=lbt AT+ADDR=addr AT+CHANNEL=channel
AT+NETID=netid AT+KEY=key AT+DELAY=delay
AT+SWITCH=switch
AT+SWITCH=switch AT+MODE=mode

Setting the Listen Before AT+LBT=1
Talk switch

Setting the Module Address AT+ADDR=1234

Sets the module operating AT+CHANNEL=23

channel

Setting the Network ID

AT+NETID=2

Set module key

AT+KEY=1234

Setting the WOR delayed AT+DELAY=1000
sleep time

Setting the software AT+SWITCH=1
switching mode switch

Setting the software AT+SWITCH=1
switching mode switch

Switching Operating Mode AT+MODE=0

EWM32M-xxxT20S User Manual Set on, refer to section 7.5 LBT enable for details. Set the module address to 1234 Set frequency to 433.125M
Set the network ID to 2 Set module key to 1234 Set WOR delayed sleep time to 1000ms. Setting on and allowing software switching Set on in configuration mode to allow software switching. Switch to pass-through mode

Query command AT+HELP=?

Description

Return example

Query AT Command Table

AT+DEVTYPE=?
AT+FWCODE=? AT+UART=?

Query Module Model Number Query Firmware Code Query baud rate and parity

DEVTYPE=EWM32M433T20S FWCODE=xxxx-x-xx AT+UART=3,0

AT+RATE=? AT+WOR=? AT+POWER=?

Query Air Rate Query WOR Role Query Transmit Power

AT+RATE=7 AT+WOR=0 AT+POWER=0

AT+TRANS=? AT+LBT=? AT+ADDR=?

Query Transmit Mode Query Listen Before Talk function switch Query Module Address

AT+TRANS=1 AT+LBT=1 AT+ADDR=1234

AT+CHANNEL=?
AT+NETID=? AT+KEY=? AT+DELAY=?
AT+SWITCH= AT+MODE=

Query Module Operating AT+CHANNEL=23

Channel

Query Network ID

AT+NETID=2

Query Module Key

()

Query WOR delayed sleep AT+DELAY=1000
time

Query software switch mode AT+SWITCH=0
switch

Query current working AT+MODE=0

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Example Description Return to AT Command Table Return to Module Model Number Return to Firmware Version Returns baud rate of 9600, 8N1 Returns the air rate as 19.2K Return to WOR receive Return to transmit power 20dBm Return to fixed point mode Return to LBT switching status Return module address is 1234 Returns the frequency as 433.125M Returns the network ID as 2 Returns ERR Returns WOR delayed sleep time of 1000ms. Software switching mode off
Returns the current pass-
20

mode (all modes can be queried)

EWM32M-xxxT20S User Manual through mode

8.2 AT Parameter Analysis

When the serial port receives the correct command, the serial port will return “Command = OK”, otherwise it will return

“=ERR”.

Command parameter

Parameter significance

Baudserial port baud rate Parityserial port parity bit

0:1200 4:19200 0:8N1

1:2400 5:38400 1:8O1

2:4800 6:57600 2:8E1

3:9600 7:115200
3:8N1

Rateairspeed RoleWOR role

0:2.4K 1:2.4K 4:9.6K 5:19.2K 0:Receive 1:Send

2:2.4K 3:4.8K 6:19.2K 7:19.2K

PeriodWOR cycle
Powertransmission power Modetransfer mode

0:500ms 1:1000ms 2:1500ms 3:2000ms 4:2500ms 5:3000ms 6:3500ms 7:4000ms 0:20dBm 1:17dBm 2:14dBm 3:10dBm 0:Transparent 1:Fixed point

LBT(listen before talk) AddrModule Address Channelmodule channel

0:off 1:on Module address 0~65535 (decimal) Module channel 0~45 (decimal)

NetidInternet ID Keykeys
DelayWOR delayed sleep

Module Network 0~255 (decimal) Module Key 0~65535 (decimal) Delay Sleep 0~65535 (decimal)

Mode(operating mode)

0: Transmission mode 1: Wake-up mode 2: Power saving mode

3: Sleep mode

8.3 Serial Port Upgrade Firmware Notes

If customers need to upgrade the firmware, they need to find the corresponding BIN file provided by the official, and then use the upper computer provided by the official to upgrade the firmware, generally users do not need to upgrade the firmware, please do not use the “AT+IAP” command. The necessary pins for upgrading must be pinned out (M1, M0, AUX, TXD, RXD, VCC, GND), and then send “AT+IAP” command to enter the upgrade mode in the configuration mode, if you need to exit the IAP upgrade mode, you need to keep powering up and wait for 60 seconds, and the program will be automatically exited, or else it will enter the upgrade mode indefinitely even if it is rebooted. If you need to exit IAP upgrade mode, you need to keep power on and wait for 60 seconds, the program will exit automatically, otherwise, even if you reboot, it will enter upgrade mode indefinitely. After entering the upgrade mode, the baud rate will be automatically switched to 115200 until it exits automatically, during which a log will be output.

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21

EWM32M-xxxT20S User Manual
9 Configuration instructions for the host computer
The following figure shows the configuration upper display interface of EWM32M-900T20S as an example. Users can switch to the command mode through M0 and M1 for quick configuration and reading of parameters in the upper display.

In the configuration of the host computer, the module address, frequency channel, network ID, and key are in decimal
display mode; where each parameter takes the range of values: Network address: 065535 Frequency channel: 045 Network ID: 0255 Key: 065535

10 Hardware design

It is recommended to use a DC regulated power supply to power this module, the power supply ripple factor should be as small as possible, and the module should be reliably grounded;
Please pay attention to the correct connection of the positive and negative terminals of the power supply, such as reverse connection may cause permanent damage to the module;
Please check the power supply to ensure that it is between the recommended supply voltages, if it exceeds the

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22

EWM32M-xxxT20S User Manual
maximum value it may cause permanent damage to the module; Please check the power supply stability, the voltage should not fluctuate significantly and frequently; In the design of power supply circuit for the module, it is often recommended to retain more than 30% of the margin,
there is the whole machine is conducive to long-term stable work; Module should be as far away as possible from the power supply, transformers, high-frequency alignments and other
electromagnetic interference in the larger part; High-frequency digital alignment, high-frequency analog alignment, power supply alignment must be avoided below
the module, if you really need to go through the module below, assuming that the module is welded in the Top Layer, the Top Layer in the contact part of the module to lay the ground copper (all paved with copper and a good ground), it must be close to the digital part of the module and alignment in the Bottom Layer; Assuming that the module is soldered or placed in the Top Layer, it is also wrong to randomly route the module in the Bottom Layer or any other layer, which will affect the spuriousness of the module as well as the reception sensitivity to varying degrees; Assuming that there is a large electromagnetic interference around the module device will also greatly affect the performance of the module, according to the intensity of the interference is recommended to stay away from the module, if the situation permits you can do appropriate isolation and shielding; Assume that there is a large electromagnetic interference around the module alignment (high-frequency digital, highfrequency analog, power supply alignment) will also greatly affect the performance of the module, according to the intensity of the interference is recommended to be appropriate away from the module, if the situation permits you can do appropriate isolation and shielding; Communication line if you use 5V level, must be connected in series with 1k-5.1k resistor (not recommended, there is still a risk of damage); Try to stay away from some TTL protocols where the physical layer is also 2.4GHz, e.g. USB3.0; The antenna mounting structure has a big impact on the module performance, make sure the antenna is exposed and preferably vertically upward; When the module is installed inside the chassis, use a good quality antenna extension cable to extend the antenna to the outside of the chassis; The antenna must not be installed inside the metal shell, which will lead to a great weakening of the transmission distance.

11 Common problems

11.1 Unsatisfactory transmission distance

When there are linear communication barriers, the communication distance will decay accordingly; Temperature, humidity, and co-channel interference, which will lead to higher communication packet loss rate; The ground absorbs and reflects radio waves, and the test results are poorer near the ground; Seawater has a strong ability to absorb radio waves, so the effect of the seaside test is poor; Metal objects near the antenna, or placed in a metal shell, the signal attenuation will be very serious; Wrong power register setting, air rate setting is too high (the higher the air rate, the closer the distance);

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23

EWM32M-xxxT20S User Manual Low voltage of power supply at room temperature is lower than the recommended value, the lower the voltage the
lower the hair power; The use of antenna and module matching degree is poor or the antenna itself quality problems.
11.2 Modules are fragile
Please check the power supply to ensure that it is between the recommended supply voltages, if it exceeds the maximum value it will cause permanent damage to the module;
Please check the power supply stability, the voltage can not be substantial frequent fluctuations; Please ensure that the installation and use process anti-static operation, high-frequency device electrostatic sensitivity; Please ensure that the installation and use of the process of humidity should not be too high, part of the components
for humidity-sensitive devices; If there is no special demand is not recommended to be used at too high or too low a temperature.
11.3 BER is too high
Near the same frequency signal interference, away from the source of interference or modify the frequency and channel to avoid interference;
Poor power supply may also cause garbled code, be sure to ensure the reliability of the power supply; Extension cords, feeder cords of poor quality or too long, can also cause high BER.
11.4 Antenna Selection

Enable both the IPEX-1 interface and the stamp hole interface at the same time, the IPEX-1 interface and the stamp hole interface can be selected at will

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24

12 Welding instructions

EWM32M-xxxT20S User Manual

12.1 Reflow temperature

Reflow Profile Characteristics

lowest temperature Tsmin

Preheating/Holding

highest temperature Tsmax

Leaded process assembly 100 150

Lead-free process assembly 150 200

TimeTsmin~Tsmin

60-120s

60-120s

slope of temperature riseTL~Tp liquid-phase temperatureTL

3/smax 183

3/sMax 217

Holding time above TL

60~90s

60~90s

Users must not exceed the The user must not exceed the

Peak package temperature Tp

temperature indicated on the product’s “Moisture Sensitivity” label.

temperature indicated on the product’s “Moisture Sensitivity” label.

Time (Tp) within 5°C of the specified

classification temperature (Tc), see the

20s

30s

following figure

Cooling slope (Tp~TL)

6/sMax

6/sMax

Time from room temperature to peak

6 minutes, max.

8 minutes, max.

temperature

The peak temperature (Tp) tolerance of the temperature profile is defined as the user’s upper limit.

12.2 Reflow temperature

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25

13 Related Models

EWM32M-xxxT20S User Manual

Product Model
E32-170T30D E32-433T20DC E32-433T20S1 E32433T20S2T E32-400T20S E32-433T30D

Carrier frequenc
ies Hz 170M 433M 433M
433M
433/470 M
433M

transmis sion power dBm 30 20 20
20
20
30

Test Distance
km 8 3 3 3
3
8

Airspeed bps
0.3k9.6k 0.3k19.2k 0.3k19.2k 0.3k19.2k
0.3k19.2k 0.3k19.2k

E32-433T30S

433M

30

8

0.3k19.2k

E32-868T20D

868M

20

3

0.3k19.2k

E32-868T20S

868M

20

3

0.3k19.2k

E32-868T30D

868M

30

8

0.3k19.2k

E32-868T30S

868M

30

8

0.3k19.2k

E32-915T20D

915M

20

3

0.3k19.2k

E32-915T20S

915M

20

3

0.3k19.2k

E32-915T30D

915M

30

8

0.3k19.2k

E32-915T30S

915M

30

8

0.3k19.2k

Package form
DIP DIP SMD SMD
SMD DIP SMD DIP SMD DIP SMD DIP SMD DIP SMD

Product Size mm 24*43 21*36
17*25.5 17*30
16*26 24*43 25*40.3 21*36 16*26 24*43 25*40.3 21*36 16*26 24*43 25*40.3

Antenna form
SMA-K SMA-K Stamp Holes IPEX/Stamp Holes IPEX/Stamp Holes SMA-K IPEX/Stamp Holes SMA-K IPEX/Stamp Holes SMA-K IPEX/Stamp Holes SMA-K IPEX/Stamp Holes SMA-K IPEX/Stamp Holes

14 Antenna Guide
14.1 Antenna Recommendation
Antenna is an important role in the communication process, often poor-quality antenna will have a great impact on the communication system, so we recommend some of the antennas as a supporting our wireless module and the performance is more excellent and reasonably priced antennas.

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26

EWM32M-xxxT20S User Manual

Product Model TX433-JZ-5 TX433-JZG-6 TX433-JW-5
TX433-JWG-7
TX433-JK-11 TX433-XPL-100 TX433-XP-200 TX433-XPH-300 TX490-JZ-5 TX490-XPL-100

style
Glue Stick Antennas Glue Stick Antenna Rubber
Stick Antenna Rubber
Stick Antenna Rubber
Stick Antenna Suction Cup Antenna Suction Cup Antenna Suction Cup Antenna Rubber
Stick Antenna Suction Cup Antenna

frequency band Hz
433M 433M 433M
433M
433M 433M 433M 433M 470/490M 470/490M

Interface SMA-J SMA-J SMA-J
SMA-J
SMA-J SMA-J SMA-J SMA-J SMA-J SMA-J

Gain dBi
2.0

Heightm m
52

Feeder cm
–

Functional Features
Ultra Short Straight, OmniDirectional Antenna

2.5

62

–

Omni-Directional Antenna

2.0

50

Bent Rubber Stick, Omni-
Directional Antenna

2.5

75

Bent Rubber Stick, Omni –
Antenna

2.5

110

Bendable Rubber Stick, Omni-
directional Antenna

Small Suction Cup Antenna, Cost

3.5

185

100

Effective

Neutral Suction Cup Antenna,

4.0

190

200

Low Loss

Large Suction Cup Antenna, High

6.0

965

300

Gain

2.0

50

Ultra Short Straight, Omni-
directional Antenna

Small Suction Cup Antenna, Cost

3.5

120

100

Effective

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27

15 Batch packing method

EWM32M-xxxT20S User Manual

Revision history

Version 1.0
1.1

Date 2025-01-23
2025-02-07

Description Initial version Recommended Wiring Diagram to Add Reserved Pull-Up Resistor Description

Issued by Lei
Lei

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28

About us

EWM32M-xxxT20S User Manual

Technical support: support@cdebyte.com Documents and RF Setting download link: www.cdebyte.com Thank you for using Ebyte products! Please contact us with any questions or suggestions: info@cdebyte.com ————————————————————————————————Phone: +86 028-61399028 Web: www.cdebyte.com Address: B5 Mould Park, 199# Xiqu Ave, High-tech District, Sichuan, China

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29

Documents / Resources

EBYTE EWM32M-xxxT20S AT Directive 20dBm Small Form Factor LoRa Wireless Module [pdf] User Manual E32-170T30D, E32-433T20DC, E32-915T30D, E32-915T30S, EWM32M-xxxT20S AT Directive 20dBm Small Form Factor LoRa Wireless Module, EWM32M-xxxT20S, AT Directive 20dBm Small Form Factor LoRa Wireless Module, Small Form Factor LoRa Wireless Module, LoRa Wireless Module, Module

References

• User Manual