How to Use E32-900M20S: Examples, Pinouts, and Specs

The E32-900M20S is a wireless serial communication module manufactured by CDEBYTE. It operates in the 900 MHz frequency band and is designed for long-range, reliable data transmission. This module is widely used in IoT applications, remote control systems, telemetry, and other scenarios requiring robust wireless communication. Its support for multiple baud rates and low power consumption makes it ideal for battery-powered devices.

• Internet of Things (IoT) networks
• Remote monitoring and control systems
• Wireless sensor networks
• Telemetry and data acquisition
• Industrial automation

The E32-900M20S module has a total of 8 pins. Below is the pinout and description:

The module supports four operating modes, determined by the states of the M0 and M1 pins:

1. Power Supply: Connect the VCC pin to a stable power source (2.3V to 5.5V) and the GND pin to ground.
2. UART Connection: Connect the RXD pin to the TX pin of your microcontroller and the TXD pin to the RX pin of your microcontroller.
3. Mode Selection: Use the M0 and M1 pins to set the desired operating mode. For normal communication, set both pins to LOW.
4. Antenna: Attach a 50Ω external antenna to the ANT pin for optimal signal strength and range.
5. Status Monitoring: Use the AUX pin to monitor the module's status (e.g., busy or idle).

Below is an example of how to connect the E32-900M20S to an Arduino UNO and send data wirelessly.

#include <SoftwareSerial.h>

// Define the RX and TX pins for SoftwareSerial
SoftwareSerial E32Serial(2, 3); // RX = Pin 2, TX = Pin 3

void setup() {
  // Initialize the serial communication with the module
  E32Serial.begin(9600); // Default baud rate of the E32-900M20S
  Serial.begin(9600);    // Serial monitor for debugging

  Serial.println("E32-900M20S Communication Test");
}

void loop() {
  // Send data to the E32 module
  E32Serial.println("Hello, E32-900M20S!");

  // Check if data is received from the E32 module
  if (E32Serial.available()) {
    String receivedData = E32Serial.readString();
    Serial.print("Received: ");
    Serial.println(receivedData);
  }

  delay(1000); // Wait for 1 second before sending the next message
}

• Voltage Levels: The module operates at 3.3V logic levels. If using a 5V microcontroller (e.g., Arduino UNO), use a voltage divider or level shifter for the RXD pin.
• Antenna Placement: Ensure the antenna is placed away from metal objects or other sources of interference to maximize range.
• Configuration: Use the configuration mode to set parameters such as baud rate, channel, and transmission power. This can be done using a USB-to-TTL adapter and the manufacturer's configuration software.
• Power Supply: Use a stable power source to avoid communication issues caused by voltage fluctuations.

1. No Communication Between Modules

   • Cause: Mismatched baud rates or channels.
   • Solution: Ensure both modules are configured with the same baud rate and channel.

2. Short Communication Range

   • Cause: Poor antenna connection or interference.
   • Solution: Check the antenna connection and ensure it is properly installed. Avoid placing the module near metal objects or other RF devices.

3. Module Not Responding

   • Cause: Incorrect wiring or power supply issues.
   • Solution: Double-check the wiring and ensure the power supply voltage is within the specified range (2.3V to 5.5V).

4. High Power Consumption

   • Cause: Module is in Normal or Wake-Up mode.
   • Solution: Use Power-Saving mode to reduce power consumption when the module is idle.

Q1: Can the E32-900M20S communicate with other frequency bands?
A1: No, the module is designed to operate specifically in the 900 MHz frequency band.

Q2: How do I configure the module's parameters?
A2: Set the M0 and M1 pins to HIGH to enter Configuration mode. Use a USB-to-TTL adapter and the manufacturer's configuration software to adjust parameters.

Q3: What is the maximum communication distance?
A3: The module can achieve up to 3 km of communication range in line-of-sight conditions with a proper antenna.

Q4: Can I use the module with a 5V microcontroller?
A4: Yes, but you must use a voltage divider or level shifter for the RXD pin to avoid damaging the module.