How to Use Elechouse ST25R3916: Examples, Pinouts, and Specs

The Elechouse ST25R3916 is a high-performance RFID/NFC reader and writer module designed for contactless data transfer applications. It supports multiple communication protocols, including ISO 14443A/B, ISO 15693, FeliCa, and NFC Forum standards. This versatile module can operate in various modes, such as reader/writer, card emulation, and peer-to-peer communication, making it suitable for a wide range of use cases.

• Access control systems
• Contactless payment terminals
• Inventory and asset tracking
• NFC-enabled device communication
• Smart home and IoT applications
• Data exchange in industrial environments

The Elechouse ST25R3916 module is packed with advanced features and specifications to ensure reliable and efficient operation.

• Operating Voltage: 3.3V to 5V
• Current Consumption: 10mA (idle), up to 150mA (active)
• Operating Frequency: 13.56 MHz
• Supported Protocols: ISO 14443A/B, ISO 15693, FeliCa, NFC Forum Type 1-5
• Communication Interface: SPI
• Operating Modes: Reader/Writer, Card Emulation, Peer-to-Peer
• Antenna: External antenna required (included with the module)
• Operating Temperature: -40°C to +85°C
• Dimensions: 40mm x 40mm

The ST25R3916 module has a standard pinout for easy integration into your projects. Below is the pin configuration:

The Elechouse ST25R3916 is straightforward to use in RFID/NFC applications. Below are the steps and best practices for integrating it into your project.

1. Power the Module: Connect the VCC pin to a 3.3V or 5V power source and the GND pin to ground.
2. Connect to a Microcontroller: Use the SPI interface (MOSI, MISO, SCK, NSS) to connect the module to your microcontroller. Ensure proper voltage levels for SPI communication.
3. Attach the Antenna: Connect the external antenna to the ANT1 and ANT2 pins. Ensure the antenna is properly tuned for optimal performance.
4. Reset the Module: Use the RST pin to reset the module during initialization.
5. Handle Interrupts: Connect the IRQ pin to a GPIO pin on your microcontroller to handle events such as tag detection or communication errors.

• Antenna Placement: Place the antenna away from metal surfaces to avoid interference and ensure maximum range.
• Power Supply: Use a stable power supply to avoid communication errors caused by voltage fluctuations.
• SPI Configuration: Configure the SPI interface on your microcontroller with the correct settings (e.g., clock polarity and phase) as specified in the ST25R3916 datasheet.
• Firmware Updates: Check for firmware updates from Elechouse to ensure compatibility with the latest NFC standards.

Below is an example of how to use the ST25R3916 module with an Arduino UNO:

#include <SPI.h>

// Pin definitions
#define NSS_PIN 10  // SPI Chip Select
#define RST_PIN 9   // Reset pin
#define IRQ_PIN 2   // Interrupt pin

void setup() {
  // Initialize serial communication
  Serial.begin(9600);
  Serial.println("Initializing ST25R3916...");

  // Initialize SPI
  SPI.begin();
  pinMode(NSS_PIN, OUTPUT);
  pinMode(RST_PIN, OUTPUT);
  pinMode(IRQ_PIN, INPUT);

  // Reset the module
  digitalWrite(RST_PIN, LOW);
  delay(10);  // Hold reset for 10ms
  digitalWrite(RST_PIN, HIGH);
  delay(10);

  Serial.println("ST25R3916 initialized successfully.");
}

void loop() {
  // Example: Check for an interrupt signal
  if (digitalRead(IRQ_PIN) == HIGH) {
    Serial.println("Interrupt detected! Processing event...");
    // Add your event handling code here
  }

  delay(100);  // Small delay to avoid spamming the serial monitor
}

1. Module Not Responding

   • Cause: Incorrect wiring or power supply issues.
   • Solution: Double-check all connections and ensure the module is powered with the correct voltage.

2. Poor Communication Range

   • Cause: Antenna placement or tuning issues.
   • Solution: Ensure the antenna is placed away from metal objects and is properly tuned.

3. SPI Communication Errors

   • Cause: Incorrect SPI settings or loose connections.
   • Solution: Verify the SPI clock polarity, phase, and wiring. Ensure the NSS pin is properly controlled.

4. Interrupts Not Triggering

   • Cause: IRQ pin not connected or misconfigured.
   • Solution: Ensure the IRQ pin is connected to a GPIO pin on the microcontroller and configured as an input.

• Q: Can the ST25R3916 read multiple tags simultaneously?
  A: Yes, the module supports anti-collision protocols, allowing it to read multiple tags in a single session.

• Q: What is the maximum communication range?
  A: The range depends on the antenna design and environment but typically ranges from 5cm to 10cm.

• Q: Is the module compatible with 5V logic?
  A: Yes, the ST25R3916 supports both 3.3V and 5V logic levels.

• Q: Can I use this module for NFC peer-to-peer communication?
  A: Yes, the ST25R3916 supports peer-to-peer communication as per the NFC Forum standards.

This documentation provides a comprehensive guide to using the Elechouse ST25R3916 module effectively. For further details, refer to the official datasheet and application notes from Elechouse.