rfid: How to solve "A BUFFER IS NOT BIG ENOUGH" error ?

Hello Friends,

Step 2: Describe your environment

I m using an mfrc522 for one project.

My OS version : Windows 8.1 Pro Arduino IDE version : 1.8.3 MFRC522 Library version : 1.3.6 Arduino device : Arduino UNO 5V 16Mhz MFRC522 device : NXP RC522 25 02 (This text written on SMD IC) MIFARE Card : MIFARE1K|S50

Step 3: Describe the problem

The issue is; Normally my MRRC522 works well, but if we remove card from MFRC522 while operation is going on then some error occur like “Authentication fail”,“Timeout in Communication” then it will recover back.

But when it will shows “A BUFFER IS NOT BIG ENOUGH” then it will not recover back only shows this error every time.

I have tried mfrc522.PCD_Reset(); and mfrc522.PCD_Init(); function of Library but is not work, i have to compulsory restart the board altogether.

## Affected file(s) or example(s): My code is Here :

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

constexpr uint8_t RST_PIN = 9;     // Configurable, see typical pin layout above
constexpr uint8_t SS_PIN = 10;     // Configurable, see typical pin layout above

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

MFRC522::MIFARE_Key key;
MFRC522::StatusCode status;

byte sector         = 2;
byte blockAddr      = 8;
byte dataBlock[18]  ={0};
byte trailerBlock   = 11;
byte buffer[18]     ={0};
byte size           = sizeof(buffer);

/**
 * Initialize.
 */
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 card

    // Prepare the key (used both as key A and as key B)
    // using FFFFFFFFFFFFh which is the default at chip delivery from the factory
    for (byte i = 0; i < 6; i++)
    {
        key.keyByte[i] = 0xFF;
    }

    Serial.println(F("Scan a MIFARE Classic PICC to demonstrate read and write."));
    Serial.print(F("Using key (for A and B):"));
    dump_byte_array(key.keyByte, MFRC522::MF_KEY_SIZE);
    Serial.println();
    
    Serial.println(F("BEWARE: Data will be written to the PICC, in sector #1"));
}

/**
 * Main loop.
 */
void loop() 
{
    // Look for new cards
    if ( ! mfrc522.PICC_IsNewCardPresent())
        return;

    // Select one of the cards
    if ( ! mfrc522.PICC_ReadCardSerial())
        return;
        
    Serial.println(F("Authenticating using key A..."));
    status = (MFRC522::StatusCode) mfrc522.PCD_Authenticate(MFRC522::PICC_CMD_MF_AUTH_KEY_A, trailerBlock, &key, &(mfrc522.uid));
    if (status != MFRC522::STATUS_OK)
    {
        Serial.print(F("PCD_Authenticate() failed: "));
        Serial.println(mfrc522.GetStatusCodeName(status));
        return;
    }

    // Read data from the block
    Serial.print(F("Reading data from block "));
    Serial.print(blockAddr);
    Serial.println(F(" ..."));
    status = (MFRC522::StatusCode) mfrc522.MIFARE_Read(blockAddr, buffer, &size);
    if (status != MFRC522::STATUS_OK) 
    {
        Serial.print(F("MIFARE_Read() failed: "));
        Serial.println(mfrc522.GetStatusCodeName(status));
    }
    Serial.print(F("Data in block ")); Serial.print(blockAddr); Serial.println(F(":"));
    dump_byte_array(buffer, 16); Serial.println();
    Serial.println();

    buffer[0]=buffer[0]+1;
    
    Serial.println(F("Authenticating again using key B..."));
    status = (MFRC522::StatusCode) mfrc522.PCD_Authenticate(MFRC522::PICC_CMD_MF_AUTH_KEY_B, trailerBlock, &key, &(mfrc522.uid));
    if (status != MFRC522::STATUS_OK)
    {
        Serial.print(F("PCD_Authenticate() failed: "));
        Serial.println(mfrc522.GetStatusCodeName(status));
        return;
    }
    
    // Write data to the block
    Serial.print(F("Writing data into block ")); Serial.print(blockAddr);
    Serial.println(F(" ..."));
    dump_byte_array(dataBlock, 16); Serial.println();
    status = (MFRC522::StatusCode) mfrc522.MIFARE_Write(blockAddr, buffer, 16);
    if (status != MFRC522::STATUS_OK) {
        Serial.print(F("MIFARE_Write() failed: "));
        Serial.println(mfrc522.GetStatusCodeName(status));
    }
    Serial.println();

    // Read data from the block (again, should now be what we have written)
    Serial.print(F("Reading data from block ")); Serial.print(blockAddr);
    Serial.println(F(" ..."));
    status = (MFRC522::StatusCode) mfrc522.MIFARE_Read(blockAddr, buffer, &size);
    if (status != MFRC522::STATUS_OK) {
        Serial.print(F("MIFARE_Read() failed: "));
        Serial.println(mfrc522.GetStatusCodeName(status));
    }
    Serial.print(F("Data in block ")); Serial.print(blockAddr); Serial.println(F(":"));
    dump_byte_array(buffer, 16); Serial.println();
        
    // Check that data in block is what we have written
    // by counting the number of bytes that are equal
    Serial.println(F("Checking result..."));
    byte count = 0;
    for (byte i = 0; i < 16; i++) 
    {
        // Compare buffer (= what we've read) with dataBlock (= what we've written)
        if (buffer[i] == dataBlock[i])
            count++;
    }
    Serial.print(F("Number of bytes that match = ")); Serial.println(count);
    if (count == 16) 
    {
        Serial.println(F("Success :-)"));
    }
     
    else 
    {
        Serial.println(F("Failure, no match :-("));
        Serial.println(F("  perhaps the write didn't work properly..."));
    }
    Serial.println();
        
    // Dump the sector data
    Serial.println(F("Current data in sector:"));
    mfrc522.PICC_DumpMifareClassicSectorToSerial(&(mfrc522.uid), &key, sector);
    Serial.println();

    // Halt PICC
    mfrc522.PICC_HaltA();
    // Stop encryption on PCD
    mfrc522.PCD_StopCrypto1();
}

/**
 * Helper routine to dump a byte array as hex values to Serial.
 */
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);
    }
}

Steps to reproduce: Step 1 : Put card on RC522 Step 2 : Remove card from RC522 while operation is going on. do above steps faster again and again at some instant you will get “A Buffer is not big enough”.

Observed Results:

Authenticating using key A...
Reading data from block 8 ...
Data in block 8:
 01 02 03 04 05 06 07 08 08 09 FF 0B 0C 0D 0E 0F

Authenticating again using key B...
PCD_Authenticate() failed: Timeout in communication.
Authenticating using key A...
PCD_Authenticate() failed: Timeout in communication.
Authenticating using key A...
Reading data from block 8 ...
MIFARE_Read() failed: The CRC_A does not match.
Data in block 8:
 01 00 4A 24 05 06 07 08 08 09 FF 0B 0C 0D 0E 0F

Authenticating again using key B...
PCD_Authenticate() failed: Timeout in communication.

Authenticating using key A...
Reading data from block 8 ...
MIFARE_Read() failed: A buffer is not big enough.
Data in block 8:
 03 00 4A 24 05 06 07 08 08 09 FF 0B 0C 0D 0E 0F

Authenticating again using key B...
Writing data into block 8 ...
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

Reading data from block 8 ...
MIFARE_Read() failed: A buffer is not big enough.
Data in block 8:
 04 00 4A 24 05 06 07 08 08 09 FF 0B 0C 0D 0E 0F
Checking result...
Number of bytes that match = 1
Failure, no match :-(
  perhaps the write didn't work properly...

Current data in sector:
   2     11   00 00 00 00  00 00 FF 07  80 69 FF FF  FF FF FF FF  [ 0 0 1 ] 
         10   00 00 00 00  00 00 00 00  00 00 00 00  00 00 00 00  [ 0 0 0 ] 
          9   00 00 00 00  00 00 00 00  00 00 00 00  00 00 00 00  [ 0 0 0 ] 
          8   04 00 4A 24  05 06 07 08  08 09 FF 0B  0C 0D 0E 0F  [ 0 0 0 ] 

Expected Results: want to solve crc error cleared without resetting/powering up the board ?

Appreciate all the help.

Thanks