How to Use NFC 4 Click ST25R3916: Examples, Pinouts, and Specs

The NFC 4 Click ST25R3916 is a compact development board designed by Mikroe and powered by the ST25R3916 NFC/RFID reader IC. This versatile component supports multiple NFC modes, including reader, card emulation, and peer-to-peer communication, making it an excellent choice for a wide range of near-field communication (NFC) applications. Its high-performance design ensures reliable communication with NFC-enabled devices, making it ideal for prototyping and integrating NFC functionality into various projects.

• Contactless payment systems
• Access control and authentication
• NFC-enabled IoT devices
• Data exchange between NFC-enabled devices
• Smart posters and tags
• Inventory and asset tracking

The NFC 4 Click board uses a standard mikroBUS™ socket for easy integration. Below is the pinout description:

1. Power Supply: Connect the NFC 4 Click to a 3.3V power source via the mikroBUS™ socket.
2. SPI Communication: Ensure the SPI pins (CS, SCK, MISO, MOSI) are properly connected to your microcontroller or development board.
3. Antenna Connection: The onboard antenna is pre-configured for NFC communication. No additional setup is required.
4. Reset and Interrupt: Use the RST pin to reset the IC and monitor the INT pin for interrupt signals.
5. Software Configuration: Use the provided Mikroe libraries or write custom SPI commands to configure the ST25R3916 for your desired NFC mode.

• Power Requirements: Ensure a stable 3.3V power supply to avoid communication errors.
• Antenna Placement: Avoid placing the board near metal objects, as they can interfere with NFC communication.
• SPI Configuration: Set the SPI clock speed and mode according to the ST25R3916 datasheet for optimal performance.
• Interrupt Handling: Use the INT pin to detect events such as tag detection or communication errors.
• Firmware Updates: Check for updates to Mikroe's libraries to ensure compatibility with the latest features.

Below is an example of how to interface the NFC 4 Click with an Arduino UNO using SPI:

#include <SPI.h>

// Pin definitions for the NFC 4 Click
#define CS_PIN 10    // Chip Select pin
#define RST_PIN 9    // Reset pin
#define INT_PIN 2    // Interrupt pin

void setup() {
  // Initialize serial communication for debugging
  Serial.begin(9600);
  
  // Initialize SPI communication
  SPI.begin();
  pinMode(CS_PIN, OUTPUT);
  pinMode(RST_PIN, OUTPUT);
  pinMode(INT_PIN, INPUT);

  // Reset the NFC module
  digitalWrite(RST_PIN, LOW);
  delay(100);
  digitalWrite(RST_PIN, HIGH);
  delay(100);

  Serial.println("NFC 4 Click Initialized");
}

void loop() {
  // Example: Send a dummy SPI command to the NFC module
  digitalWrite(CS_PIN, LOW); // Select the NFC module
  SPI.transfer(0x00);        // Send a dummy command
  digitalWrite(CS_PIN, HIGH); // Deselect the NFC module

  // Check for interrupt signal
  if (digitalRead(INT_PIN) == HIGH) {
    Serial.println("Interrupt detected!");
    // Handle the interrupt (e.g., read tag data)
  }

  delay(500); // Wait for a while
}

1. No Response from the NFC Module

   • Cause: Incorrect SPI configuration or wiring.
   • Solution: Double-check the SPI connections and ensure the SPI clock speed matches the ST25R3916 requirements.

2. NFC Tag Not Detected

   • Cause: Improper antenna placement or interference.
   • Solution: Ensure the tag is within the NFC range and avoid placing the board near metal objects.

3. Interrupt Pin Not Triggering

   • Cause: Incorrect interrupt handling or configuration.
   • Solution: Verify the INT pin connection and ensure the firmware is configured to enable interrupts.

4. Power Supply Issues

   • Cause: Insufficient or unstable power supply.
   • Solution: Use a regulated 3.3V power source and check for voltage drops.

• Q: Can the NFC 4 Click work with 5V systems?
  A: No, the board operates at 3.3V. Use a level shifter if interfacing with a 5V system.

• Q: What is the maximum NFC range?
  A: The range depends on the antenna and tag size but typically extends up to 10 cm.

• Q: Does Mikroe provide software libraries for this board?
  A: Yes, Mikroe provides libraries and example code for various platforms, including Arduino and MikroC.

• Q: Can I use this board for peer-to-peer communication?
  A: Yes, the ST25R3916 supports peer-to-peer NFC communication.

This documentation provides a comprehensive guide to using the NFC 4 Click ST25R3916. For further assistance, refer to the official Mikroe documentation or contact their support team.