I ordered Ntag215 from Aliexpress. The tags are identified just fine, yet I have issues writing/reading to them because of failed authentication. I am using Arduino Uno + RFID-RC522 module. This is my code below:

#include <SPI.h>
#include <MFRC522.h>

#define RST_PIN 9  //
#define SS_PIN 10  //

MFRC522 mfrc522(SS_PIN, RST_PIN);  // Create MFRC522 instance

void setup() {
  Serial.begin(9600);  // Initialize serial communications with the PC
  while (!Serial)
    ;                  // Do nothing if no serial port is opened (added for Arduinos based on ATMEGA32U4)
  SPI.begin();         // Init SPI bus
  mfrc522.PCD_Init();  // Init MFRC522
  Serial.println(F("Scan PICC to see UID, type, and data blocks..."));

void loop() {
  // Reset the loop if no new card present on the sensor/reader. This saves the entire process when idle.
  if (!mfrc522.PICC_IsNewCardPresent()) {

  // Select one of the cards
  if (!mfrc522.PICC_ReadCardSerial()) {
  Serial.print(F("Card UID:"));
  dump_byte_array(mfrc522.uid.uidByte, mfrc522.uid.size);
  Serial.print(F("PICC type: "));
  MFRC522::PICC_Type piccType = mfrc522.PICC_GetType(mfrc522.uid.sak);

  MFRC522::MIFARE_Key key = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
  MFRC522::StatusCode status = mfrc522.PCD_Authenticate(MFRC522::PICC_CMD_MF_AUTH_KEY_A, 1, &key, &(mfrc522.uid));

void dump_byte_array(byte *buffer, byte bufferSize) {
    for (byte i = 0; i < bufferSize; i++) {
        Serial.print(buffer[i] < 0x10 ? " 0" : " ");
        Serial.print(buffer[i], HEX);

And this is the output I get.

01:27:26.704 -> Scan PICC to see UID, type, and data blocks...
01:27:30.357 -> Card UID: 04 CB 4A 57 19 61 80
01:27:30.390 -> PICC type: MIFARE Ultralight or Ultralight C
01:27:30.422 -> Timeout in communication.

Always get Timeout in communication. With Mifare 1KB tags this is not an issue. Any idea?

  • it times out after 32 ms ... maybe the timeout setting is too short
    – jsotola
    Apr 5 at 0:39

1 Answer 1


Ok after more trial and error and research I have made it possible to Write and Read to Ntag215. Here are code snippets for writing and reading. It was not required to Authenticate to write the data the tag.

Writing: It is actually quite simple. The main rule is that the writing can start from the page 4. And the bufferSize has to be 4. Here is example just writing "A" character to the tag.

    char charToProgram = "A";
    byte data = charToProgram;       // Data to write (ASCII character "A")
    byte blockAddr = 4;  // Block address to write to

    // Write the data to the tag
    MFRC522::StatusCode status = reader.MIFARE_Ultralight_Write(4, &data, 4);

    if (status == MFRC522::StatusCode::STATUS_OK) {
      Serial.println("SUCCESS! Wrote to card!");


    int blockAddr = 4;  // Block address to read from
    byte data[18];
    byte size = 18;
    // Write the data to the tag
    MFRC522::StatusCode status = reader.MIFARE_Read(blockAddr, data, &size);

    if (status == MFRC522::StatusCode::STATUS_OK) {
      Serial.print("Read character: ");
      Serial.println((char) data[0]);

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.