int MFRC522::writeToTag(byte block, byte *data) {
int status, i, len;
byte buffer[18];
buffer[0] = MF1_WRITE;
buffer[1] = block;
calculateCRC(buffer, 2, &buffer[2]);
status = commandTag(MFRC522_TRANSCEIVE, buffer, 4, buffer, &len);
if ((status != MI_OK) || (len != 4) || ((buffer[0] & 0x0F) != 0x0A)) {
status = MI_ERR;
}
if (status == MI_OK) {
for (i = 0; i < 16; i++) {
buffer[i] = data[i];
}
calculateCRC(buffer, 16, &buffer[16]);
status = commandTag(MFRC522_TRANSCEIVE, buffer, 18, buffer, &len);
if ((status != MI_OK) || (len != 4) || ((buffer[0] & 0x0F) != 0x0A)) {
status = MI_ERR;
}
}
return status;
}
void MFRC522::haltTag() {
int status, len;
byte buffer[4];
buffer[0] = MF1_HALT;
buffer[1] = 0;
calculateCRC(buffer, 2, &buffer[2]);
clearBitMask(Status2Reg, 0x08); // turn off encryption
status = commandTag(MFRC522_TRANSCEIVE, buffer, 4, buffer, &len);
}
int MFRC522::requestTag(byte mode, byte *data) {
int status, len;
writeToRegister(BitFramingReg, 0x07); // TxLastBists = BitFramingReg[2..0]
data[0] = mode;
status = commandTag(MFRC522_TRANSCEIVE, data, 1, data, &len);
if ((status != MI_OK) || (len != 0x10)) {
status = MI_ERR;
}
return status;
}
int MFRC522::readFromTag(byte block, byte *result) {
int status, len;
result[0] = MF1_READ;
result[1] = block;
calculateCRC(result, 2, &result[2]);
status = commandTag(MFRC522_TRANSCEIVE, result, 4, result, &len);
if ((status != MI_OK) || (len != 0x90)) {
status = MI_ERR;
}
return status;
}
int MFRC522::authenticate(byte mode, byte block, byte *key, byte *serial) {
int i, status, len;
byte buffer[12];
//Verify the command block address + sector + password + tag serial number
buffer[0] = mode; // 0th byte is the mode
buffer[1] = block; // 1st byte is the block to address.
for (i = 0; i < 6; i++) { // 2nd to 7th byte is the authentication key.
buffer[i+2] = key[i];
}
for (i = 0; i < 4; i++) { // 8th to 11th byte is the serial of the tag.
buffer[i+8] = serial[i];
}
status = commandTag(MFRC522_AUTHENT, buffer, 12, buffer, &len);
if ((status != MI_OK) || (!(readFromRegister(Status2Reg) & 0x08))) {
status = MI_ERR;
}
return status;
}
byte MFRC522::selectTag(byte *serial) {
int i, status, len;
byte sak;
byte buffer[9];
buffer[0] = MF1_SELECTTAG;
buffer[1] = 0x70;
for (i = 0; i < 5; i++) {
buffer[i+2] = serial[i];
}
calculateCRC(buffer, 7, &buffer[7]);
status = commandTag(MFRC522_TRANSCEIVE, buffer, 9, buffer, &len);
if ((status == MI_OK) && (len == 0x18)) {
sak = buffer[0];
}
else {
sak = 0;
}
return sak;
}
int MFRC522::antiCollision(byte *serial) {
int status, i, len;
byte check = 0x00;
writeToRegister(BitFramingReg, 0x00); // TxLastBits = BitFramingReg[2..0]
serial[0] = MF1_ANTICOLL;
serial[1] = 0x20;
status = commandTag(MFRC522_TRANSCEIVE, serial, 2, serial, &len);
len = len / 8; // len is in bits, and we want each byte.
if (status == MI_OK) {
// The checksum of the tag is the ^ of all the values.
for (i = 0; i < len-1; i++) {
check ^= serial[i];
}
// The checksum should be the same as the one provided from the
// tag (serial[4]).
if (check != serial[i]) {
status = MI_ERR;
}
}
return status;
}
