Hi!
I have a similar problem with the same configuration.
After reading this and similar threads, it was quite obvious that pins 4 and 10 can not be used.
Therefore I used pin 8 as SS pin for my RFID-RC522.
The problem is that if the memory card is inside, I would see any response on Serial monitor when RFID device is scanned, or there would be error message: "MIFARE_Read() failed: The CRC_A does not match."
The code is following:
/*
* Dump block 0 of a MIFARE RFID card using a RFID-RC522 reader
* Uses MFRC522 - Library to use ARDUINO RFID MODULE KIT 13.56 MHZ WITH TAGS SPI W AND R BY COOQROBOT.
-----------------------------------------------------------------------------
* Pin layout should be as follows:
* Signal Pin Pin Pin
* Arduino Uno Arduino Mega MFRC522 board
* ------------------------------------------------------------
* Reset 9 5 RST
* SPI SS 10 53 SDA
* SPI MOSI 11 52 MOSI
* SPI MISO 12 51 MISO
* SPI SCK 13 50 SCK
*
* Hardware required:
* Arduino
* PCD (Proximity Coupling Device): NXP MFRC522 Contactless Reader IC
* PICC (Proximity Integrated Circuit Card): A card or tag using the ISO 14443A interface, eg Mifare or NTAG203.
* The reader can be found on eBay for around 5 dollars. Search for "mf-rc522" on ebay.com.
*/
#include <SPI.h>
#include <MFRC522.h>
#define SS_PIN 8 //Arduino Uno; CHANGED TO 8 TO AVOID CONFLICT WITH ETHERNET
#define RST_PIN 9
MFRC522 mfrc522(SS_PIN, RST_PIN); // Create MFRC522 instance.
void setup() {
Serial.begin(9600); // Initialize serial communications with the PC
SPI.begin(); // Init SPI bus
mfrc522.PCD_Init(); // Init MFRC522 card
Serial.println("Print block 0 of a MIFARE PICC ");
}
void loop() {
// Prepare key - all keys are set to FFFFFFFFFFFFh at chip delivery from the factory.
MFRC522::MIFARE_Key key;
for (byte i = 0; i < 6; i++) key.keyByte[i] = 0xFF;
// Look for new cards
if ( ! mfrc522.PICC_IsNewCardPresent()) {
return;
}
// Select one of the cards
if ( ! mfrc522.PICC_ReadCardSerial()) return;
Serial.print("Card UID:"); //Dump UID
for (byte i = 0; i < mfrc522.uid.size; i++) {
Serial.print(mfrc522.uid.uidByte[i] < 0x10 ? " 0" : " ");
Serial.print(mfrc522.uid.uidByte[i], HEX);
}
Serial.print(" PICC type: "); // Dump PICC type
byte piccType = mfrc522.PICC_GetType(mfrc522.uid.sak);
Serial.println(mfrc522.PICC_GetTypeName(piccType));
byte buffer[18];
byte block = 0;
byte status;
//Serial.println("Authenticating using key A...");
status = mfrc522.PCD_Authenticate(MFRC522::PICC_CMD_MF_AUTH_KEY_A, block, &key, &(mfrc522.uid));
if (status != MFRC522::STATUS_OK) {
Serial.print("PCD_Authenticate() failed: ");
Serial.println(mfrc522.GetStatusCodeName(status));
return;
}
// Read block
byte byteCount = sizeof(buffer);
status = mfrc522.MIFARE_Read(block, buffer, &byteCount);
if (status != MFRC522::STATUS_OK) {
Serial.print("MIFARE_Read() failed: ");
Serial.println(mfrc522.GetStatusCodeName(status));
}
else // Dump data
for (byte index = 0; index < 16; index++) {
Serial.print(buffer[index] < 0x10 ? " 0" : " ");
Serial.print(buffer[index], HEX);
if ((index % 4) == 3) Serial.print(" ");
}
Serial.println(" ");
mfrc522.PICC_HaltA(); // Halt PICC
mfrc522.PCD_StopCrypto1(); // Stop encryption on PCD
}
I have tried using other pins, but with no success. Without memory card everything works perfectly.
EDIT:
If SD SPI disabled, as SurferTim suggested, everything works...