E28-2G4T12S LoRa Module User Manual

EBYTE E28-2G4T12S 2.4GHz TTL LoRa Module

1. Product Overview

The E28-2G4T12S is an UART module based on the SEMTECH SX1280 chip. It supports transparent transmission and operates in the 2.4GHz band, utilizing LoRa, FLRC, and GFSK modulations. The module features SMD packing with both IPX and PCB antenna interfaces, and provides a 3.3V TTL output.

Leveraging LoRa direct sequence spread spectrum (DSSS) technology, it offers extended communication range and enhanced anti-interference capabilities. The integrated forward error correction (FEC) algorithm improves coding efficiency and error correction. The module can proactively correct interfered data packets, significantly boosting communication range and reliability.

Data encryption and compression are also featured. Data transmitted wirelessly is randomized, making interception difficult. The compression function reduces transmission duration and the probability of data interference, thereby improving reliability and transmission efficiency.

1.1 Features

Supports GFSK, FLRC, and LoRa modulation modes.
Enables high-speed continuous transmission without subcontracting.
Provides RSSI for signal quality evaluation.
Supports fixed transmission, broadcast, and monitoring.
Achieves communication distances up to 3km in ideal conditions.
Features a maximum transmitting power of 12dBm, adjustable via software.
Operates in the global license-free ISM 2.4GHz band.
Supports air data rates from 1kbps to 2Mbps.
Low power consumption suitable for battery-powered applications.
Wide power supply range: 2.3V to 5.5V DC (over 5.5V may affect performance).
Industrial-grade design, operating temperature from -40°C to 85°C.
Optional PCB and IPEX antenna interfaces for flexible integration.

1.3 Application

Smart Home and Industrial Sensors
Security Systems, Location Systems
Wireless Remote Controls, UAVs
Wireless Game Controllers
Healthcare Products
Wireless Voice Communication, Wireless Headsets
Automotive Industry Applications

2. Technical Parameters

2.1 Limit Parameters

Main Parameter	Performance		Note
	Min	Max
Voltage Supply [V]	0	5.5	Voltage over 5.5V will cause permanent damage to the module.
Blocking Power [dBm]	-	10	Chances of burn are slim when modules are used in short distance.
Operating Temperature [°C]	-40	+85	-

2.2 Operating Parameters

Main Parameter	Performance			Note
	Min	Typ	Max
Voltage Supply [V]	2.3	5.0	5.5	≥5.0V ensures output power.
Communication Level [V]	-	3.3	-	For 5V TTL, it may be at risk of burning down.
Operating Temperature [°C]	-40	-	+85	-
Frequency [MHz]	2400	-	2500	ISM band.
Power Consumption	Transmitting Current [mA]	-	-	46	Instant power consumption.
	Receiving Current [mA]	-	-	20	-
	Turn-off Current [µA]	-	-	8	Software is shut down.
RF Parameters	Transmitting Power [dBm]	11.5	12.0	13.5	-
	Receiving Sensitivity [dBm]	-130	-132	-134	Air data rate: 1.0kbps.
	Air Data Rate [bps]	1k	1k	2M	Defined by user via programming.

Main Parameter	Description	Note
Distance	3000m	Test condition: clear and open area, antenna gain: 5dBi, antenna height: 2.5m, air data rate: 1kbps.
FIFO	121 Byte / 221 Byte	Max. Transmitting length per packet / Continuous transmission mode.
Modulation	GFSK / LoRa / FLRC	Continuous transmission mode.
Interface	UART	TTL.
Package	SMD	-
Connector	1.27mm	-
Size	17.5*28.7mm	-
Antenna	IPEX/PCB	50Ω Impedance.

3. Dimension and Pin Definition

The module measures approximately 28.7 x 17.5 mm. It features an IPEX connector and an antenna pad.

Pin No.	Pin Name	Pin Direction	Function
1	GND	Ground	Ground
2	NC	-	Disconnected
3	M0	Input	M2, M1, and M0 jointly decide the 8 operation modes. (Cannot be floated, can be grounded if not used)
4	M1	Input	M2, M1, and M0 jointly decide the 8 operation modes. (Cannot be floated, can be grounded if not used)
5	M2	Input	M2, M1, and M0 jointly decide the 8 operation modes. (Cannot be floated, can be grounded if not used)
6	RXD	Input	TTL serial input, connected to external TXD output pin. Can be configured as open-drain or pull-up input; refer to Parameter Configuration.
7	TXD	Output	TTL serial output, connected to external RXD input pin. Can be configured as open-drain or push-pull output; refer to Parameter Configuration.
8	AUX	Output	Indicates module operation status. Outputs low level during initialization after power-on and self-check. Can be configured as open-drain or push-pull output; refer to Parameter Configuration. (Can be floated)
9	VCC	-	Module power source positive reference. Voltage range: 2.3 ~ 5.5V DC.
10~11	GND	Ground	Ground
12~19	NC	-	Disconnected
20	GND	Ground	Ground

4. Recommended Connection Diagram

A typical connection diagram illustrates the interface between the module and an MCU (e.g., STM8L MCU). The wireless UART module uses TTL level, requiring connection to an MCU with TTL level. For 5V MCUs, a 4~10K pull-up resistor may be necessary for the TXD and AUX pins.

Example MCU Connection (STM8L):

Module Pin 19 (PC1) to MCU Pin 18
Module Pin 1 (PC1) to MCU Pin 19
Module Pin 2 (PC0) to MCU Pin 17
Module Pin 3 (PA0) to MCU Pin 16 (M2)
Module Pin 4 (PA1) to MCU Pin 15 (M1)
Module Pin 5 (PA2) to MCU Pin 20 (M0)
Module Pin 6 (PA3) to MCU Pin 4 (RXD)
Module Pin 7 (VSS) to MCU Pin 1 (USART_RX)
Module Pin 8 (VDD) to MCU Pin 5 (USART_TX)
Module Pin 9 (PB0) to MCU Pin 14 (AUX)
Module Pin 10~11 (GND) to MCU Pin 13 (VCC)
Module Pin 12~19 (NC) to MCU Pin 12 (GND)
Module Pin 20 (GND) to MCU Pin 11 (PB1)

Connection Notes:

The wireless UART module uses TTL level, connect to MCU with TTL level.
For some 5V MCUs, a 4~10K pull-up resistor may be needed on the TXD and AUX pins.

5. Functional Description

5.1. Fixed Transmission

In fixed transmission mode, data is sent to a specific target address and channel. Only modules configured with that address and channel will receive the data. Data packets consist of target address, target channel, and the actual data.

Example: A packet sent with address 00 03 04 and channel AA BB CC will be received by modules configured for this address and channel. Other modules (e.g., 00 05 04, 00 07 06) will not output the data.

5.2. Broadcast

In broadcast mode, data is sent to a broadcast address and channel. All modules listening on that broadcast channel will receive the data, regardless of their specific address.

Example: A packet sent with broadcast address FF FF 04 and channel AA BB CC will be received by all modules configured for channel AA BB CC. Modules like 00 03 04 and 00 05 04 will receive it, while 00 07 06 might not if it's not configured for the broadcast channel.

5.3. Broadcast Address

To enable broadcast, set the module's address to 0xFFFF or 0x0000 and the channel to 0x04. When transmitting in this mode, all modules on channel 0x04 will receive the broadcast data.

5.4. Monitor Address

To monitor broadcast data, set the module's address to 0xFFFF or 0x0000 and the channel to 0x04. When set as a receiver, it will receive data transmitted by modules using channel 0x04.

5.5. Module Reset

Upon power-on, the AUX output goes low during hardware self-check and mode initialization based on M0/M1 settings. After completion, AUX goes high, indicating the module is ready. Users should wait for the AUX rising edge before proceeding.

5.6. AUX Description

The AUX pin provides status indications for wireless send/receive buffers and self-check. It signals data readiness for wireless transmission or UART reception, and indicates if the module is undergoing initialization.

5.6.1 Indication of Serial Output

The AUX pin can be used to wake up the external MCU. Note that AUX shows no delay under continuous mode.

5.6.2 Indication of Wireless Transmission

Under sub-packet mode, the buffer size is determined by the sub-packet size (e.g., 2048 bytes for 221-byte packets). AUX=1 allows initiating transmission of up to 2048 bytes.

In continuous transmission mode, AUX=1 indicates the module is busy. This is not suitable for waking up the MCU due to the rapid data transmission. AUX=1 signifies all serial data has been transmitted via RF, and the module is idle.

5.6.3 Module in Configuration Process

This state occurs during resetting or when exiting sleep mode.

6. Operation Modes

The module supports four operation modes, controlled by pins M0 and M1:

Mode (0-3)	M2	M1	M0	Introduction	Remarks
0 - Transmission Mode	1	0	0	Serial port on, RF on, transparent transmission	Air data rate manually configurable and automatically adjusted with baud rate. Baud rates must match on both sides for continuous transmission.
1 - RSSI Mode	1	0	1	Serial port on, RF on, RSSI on	Outputs RSSI value via serial port every 100ms.
2 - Ranging Mode	1	1	0	Reserved	-
3 - Configuration Mode	1	1	1	Serial port on, RF off, parameter configuration	Baud rate fixed at 9600 8N1.
4 - Low Power Mode	0	X	X	Lowest power consumption in low power mode.	When M2 is high, it's in normal working condition. When M2 is low, it's in low power mode.

6.1. Mode Switch

Mode switching is determined by the logic levels of M2, M1, and M0, controllable via the MCU's GPIO pins.

If the module is idle (AUX high), it starts operating in the new mode immediately after any pending data transmission is complete.
Mode switches are only valid when AUX is high, or the switch may be delayed.
When switching modes while large amounts of data are being transmitted continuously, the switch might be invalid until data transmission is finished. It's recommended to check AUX status and switch 2ms after AUX goes high.
Entering configuration mode from other modes can lead to sleep mode after data processing, saving energy. For example, after transmitting data in Mode 0, the module can switch to sleep mode, and the MCU can also enter sleep mode. The module will automatically enter sleep mode 1ms later.
This feature allows for quick mode switching without needing to constantly check AUX status. For instance, switching from transmit to receive mode can be done by using an external interrupt on AUX change, allowing the MCU to sleep beforehand.
This flexible and efficient operation simplifies MCU control, reduces system load, and enhances efficiency and energy saving.

6.2. Transmission Mode (Mode 0)

In this mode, data is transmitted transparently, meaning the receiver gets the data in its original format. Normal communication requires matching air data rates, addresses, and channels. Continuous transmission requires identical baud rates on both ends and supports large file transfers at baud rates from 1200bps to 115200bps.

6.3. RSSI Mode (Mode 1)

The module outputs the current 2.4GHz signal's RSSI value every 100ms to assess channel quality. The value is presented in HEX compliment format.

6.4. Ranging Mode (Mode 2)

This mode is reserved.

6.5. Sleep Mode (Mode 3)

In this mode, the baud rate is fixed at 9600 8N1.

7. Command Format

Under configuration mode (M0=1, M1=1, M2=1), the following parameters can be configured. Note that only 9600 baud rate and 8N1 format are supported for setting.

No.	Command Format	Description
1	C0 + working parameters	C0 followed by 5 bytes of working parameters in hexadecimal format (6 bytes total). Must be sent consecutively. Parameters are saved upon power-down.
2	C1+C1+C1	Three C1 commands sent in hexadecimal format. The module returns saved parameters consecutively.
3	C2 + working parameters	C2 followed by 5 bytes of working parameters in hexadecimal format (6 bytes total). Must be sent consecutively. Parameters are NOT saved upon power-down.
4	C3+C3+C3	Three C3 commands sent in hexadecimal format. The module returns version information consecutively.
5	C4+C4+C4	Three C4 commands sent in hexadecimal format. The module will reset once and then return to normal operation.
6	E2+E2+E2	In transparent transmission mode, sending three E2 commands in HEX format opens a 10-second parameter configuration window. Parameters can be set using the C0 command within this window. The module will apply new parameters after 10 seconds.
7	E3+E3+E3	In transparent transmission mode, sending three E3 commands in HEX format opens a 10-second parameter configuration window. Parameters can be set using a 6-byte C0 command within this window. The module will apply new parameters after 10 seconds.

7.1. Default Parameter Values

Model	Frequency	Address	Channel	Air Data Rate	Baud Rate	Parity	Transmitting Power
E28-2G4T12S	2.4GHz	0x0000	0x13	10kbps	9600	8N1	12dBm

7.2. Reading Operating Parameters

To read current operating parameters, send the command C1+C1+C1 (in HEX format) to the serial port while in configuration mode (M0=1, M1=1, M2=1). The module will respond with the current parameter values, e.g., C0 00 00 13 18 04.

7.3. Reading Version Number

In configuration mode (M0=1, M1=1, M2=1), send the command C3+C3+C3 (in HEX format). The module will return current configuration parameters, including model information (e.g., E28 series), version number, power, and other features.

7.4. Reset Command

In configuration mode (M0=1, M1=1, M2=1), send the command C4+C4+C4 (in HEX format) to reset the module. During the reset process, AUX outputs low. After reset, AUX outputs high, and the module is ready for operation. Users can then switch modes or issue new commands.

7.5. Parameter Configuration Commands

No.	Item	Description	Remarks
0	HEAD	Fix 0xC0 or 0xC2. This frame data is a control command.	C0: Save parameters on power-down. C2: Do not save parameters on power-down.
1	ADDH	High address byte of module (default 00H).	00H-FFH
2	ADDL	Low address byte of module (default 00H).	00H-FFH
3	SPED	UART parity bit:	The serial modes can be different on two sides. Under normal mode, modes can differ. Under continuous transmission mode, baud rates must be the same.
		7 6		0 0: 8N1 (default)
		0 1: 8O1
		1 0: 8E1
3	SPED	TTL UART baud rate (bps):	Under normal mode, modes can differ. Under continuous transmission mode, baud rates must be the same.
		5 4 3		0 0 0: 1200
		0 0 1: 4800
		0 1 0: 9600 (default)
		0 1 1: 19200
		1 0 0: 57600
		1 0 1: 115200
		1 1 0: 460800
1	SPED	Air data rate (bps):	Under non-continuous transmission mode, baud rate does not affect RF parameters. Under continuous transmission mode, baud rate determines air data rate, affecting transmission speed and range. Lower air data rates offer longer distance and better anti-interference. Air data rates must match on both sides.
		Self-adaptive (continuous transmission)
		0 0 0: 1k
		0 0 1: 1k
		0 1 0: 5k
		0 1 1: 10k (default)
		1 0 0: 50k
		1 0 1: 100k
		1 1 0: 1M (FLRC)
		1 1 1: 2M (FSK)
4	CHAN	Communication Channel	Default: 0x18. Formulas provided for calculating channel based on air data rate and transmission mode.
		Fixed transmission enabling bit (similar to Modbus)	0: Transparent transmission mode 1: Fixed transmission mode. In fixed mode, the first three bytes of data frame are used for address/channel.
6	Reserved	-	-
5	Reserved	-	-
4	Measuring mode device type (reserved)	0: Slave (default) 1: Master	Under range measuring mode, slave address is determined by ADDH and ADDL.
3	LBT switch	0: Turn off LBT (default) 1: Turn on LBT	Supports LBT below 115200bps. LBT may affect continuous transmission.
2	IO driving mode	1: TXD, AUX push-pull output, RXD pull-up input 0: TXD, AUX open-circuit output, RXD open-circuit input	Used for internal pull-up resistor and level adaptability. May require external pull-up.
1	Transmission power (approximated)	0 0: 12dBm (default) 0 1: 10dBm 1 0: 7dBm 1 1: 4dBm	External power source must provide 100mA+ current with low ripple (<100mV). Low power transmission is not recommended for efficiency.

8. Hardware Design

Consider the following for optimal hardware design and module performance:

Use a DC stabilized power supply with minimal ripple and ensure reliable grounding.
Verify correct polarity for power supply connections; reverse connection can cause permanent damage.
Ensure the power supply voltage stays within the recommended range (2.3V-5.5V); exceeding the maximum value can damage the module.
Maintain power supply stability; avoid frequent voltage fluctuations.
When designing the power supply circuit, reserve at least 30% margin for long-term stable operation.
Position the module away from power supplies, transformers, high-frequency wiring, and other sources of significant electromagnetic interference (EMI).
Avoid routing high-frequency digital, analog, or power traces directly under the module. If routing is necessary, ensure the module is on the Top Layer, with copper spread on its contact area (well-grounded) and routed close to the digital part on the Bottom Layer.
Incorrect routing over other layers (not the Top Layer where the module is soldered/placed) can negatively affect the module's spurs and receiving sensitivity.
If devices with strong EMI are nearby, keep them away from the module and consider appropriate isolation or shielding.
If communication lines use 5V levels, a 1k-5.1k resistor in series is recommended, though not foolproof.
Avoid physical layers operating at 2.4GHz, such as USB3.0, in close proximity.
Antenna mounting significantly impacts performance. Ensure the antenna is exposed and preferably oriented vertically upwards. If the module is enclosed, use an extension cable to position the antenna externally.
Do not install the antenna inside a metal case, as this will severely degrade transmission distance.

9. FAQ

9.1 Communication Range is Too Short

Obstacles can affect communication distance.
Data loss rate is influenced by temperature, humidity, and co-channel interference.
Performance is reduced when testing near ground due to radio wave absorption and reflection.
Testing near sea water is also affected due to absorption.
Signal strength is impacted if the antenna is near metal objects or within a metal case.
Incorrect power register settings or excessively high air data rates (higher rate = shorter distance) can reduce range.
Low power supply voltage (below 2.5V at room temperature) reduces transmitting power.
Antenna quality or poor matching between the antenna and module can limit range.

9.2 Module is Easy to Damage

Ensure the power supply source is within the 2.0V-3.6V range. Voltages above 3.6V can damage the module.
Verify power source stability; avoid significant voltage fluctuations.
Implement antistatic measures during installation and use, as high-frequency devices are susceptible to electrostatic discharge.
Ensure humidity levels are within the specified range, as some components are humidity-sensitive.

9.3 BER (Bit Error Rate) is High

Check for nearby co-channel signal interference. Move away from interference sources or adjust frequency/channel.
Unstable power supply can cause errors. Ensure a reliable power source.
Poor quality or excessively long extension lines and feeders can lead to a high bit error rate.

10. Production Guidance

10.1 Reflow Soldering Temperature

Recommended temperature profiles for Sn-Pb and Pb-Free assembly:

Profile Feature	Curve Characteristics	Sn-Pb Assembly (Sn63/Pb37)	Pb-Free Assembly (Sn96.5/Ag3/Cu0.5)
Preheat Temperature Min (Tsmin)	Min preheating temp.	100°C	150°C
Preheat Temperature Max (Tsmax)	Max preheating temp.	150°C	200°C
Preheat Time (Tsmin to Tsmax) (ts)	Preheating time	60-120 sec	60-120 sec
Average Ramp-up Rate (Tsmax to Tp)	Average ramp-up rate	3°C/second max	3°C/second max
Liquidus Temperature (TL)	Liquid phase temp.	183°C	217°C
Time (tL) Maintained Above (TL)	Time above liquid phase line	60-90 sec	30-90 sec
Peak Temperature (Tp)	Peak temperature	220-235°C	230-250°C
Average Ramp-down Rate (Tp to Tsmax)	Average ramp-down rate	6°C/second max	6°C/second max

10.2 Reflow Soldering Curve

The reflow soldering curve illustrates the temperature profile over time, including Preheat, Ramp-up, Peak temperature (Critical Zone), and Ramp-down stages.

11. Related Products

EBYTE offers several wireless modules based on the SX1280 chip:

Type	IC	Frequency [Hz]	Power [dBm]	Distance [km]	Size [mm]	Package	Interface
E28-2G4T12S	SX1280	2.4G	12.5	3	17.5*28.7	SMD	TTL
E28-2G4M27S	SX1280	2.4G	27	8	15*26.5	SMD	SPI
E28-2G4M20S	SX1280	2.4G	20	6	15*26.5	SMD	SPI
E28-2G4M12S	SX1280	2.4G	12.5	3	25*14	SMD	SPI

12. Antenna Guidance

12.1 Antenna Recommendation

Antenna selection is crucial for communication system performance. EBYTE recommends the following antennas for their wireless modules, balancing performance and price:

Model	Type	Frequency [Hz]	Gain [dBi]	Size [mm]	Feeder	Interface	Feature
TX2400-NP-5010	FPC	2.4G	2.0	10x50	-	IPEX	FPC antenna
TX2400-JZ-3	Rubber	2.4G	2.0	30	-	SMA-J	Straight antenna, ultra short
TX2400-JZ-5	Rubber	2.4G	2.0	50	-	SMA-J	Straight antenna, ultra short
TX2400-JW-5	Rubber	2.4G	2.0	50	-	SMA-J	Fixed bending antenna
TX2400-JK-11	Rubber	2.4G	2.5	110	-	SMA-J	Flexible antenna, omnidirectional
TX2400-JK-20	Rubber	2.4G	3.0	200	-	SMA-J	Flexible antenna, omnidirectional
TX2400-XPL-150	Sucker	2.4G	3.5	150	150	SMA-J	Small sucker antenna, high gain

12.2 Antenna Selection

The module supports both PCB (default) and IPEX antenna connectors.

13. Package for Batch Order

The module is supplied in trays suitable for batch orders. Each tray contains 800 pieces. Dimensions for the tray and individual modules are provided.

Revision History

Version	Date	Description	Operator
1.0	2018-01-08	Initial Version	huaa
1.1	2018-04-16	Content added	huaa
1.2	2018-05-24	Content added	Huaa
1.3	2018-07-20	Name updated	Huaa
1.4	2019-3-12	Content added	Ray
1.5	2020-05-11	Parameter correction	du

About Us

Website: www.ebyte.com

Sales: info@cdebyte.com

Support: support@cdebyte.com

Tel: +86-28-61399028 Ext. 812

Fax: +86-28-64146160

Address: Innovation Center B333~D347, 4# XI-XIN road, High-tech district (west), Chengdu, Sichuan, China

[EBYTE Logo] Chengdu Ebyte Electronic Technology Co.,Ltd.

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