 	Post: Response packet contains OK status and serial number of the tag selected
 
 */
-void MF_SNR(unsigned char DADD) {
-	unsigned char A[] = { DADD, 0x03, CMD_GET_SNR, 0x26, 0x00 };
+void MF_SNR(void) {
+	unsigned char A[] = { 0x00, 0x03, CMD_GET_SNR, 0x26, 0x00 };
 	unsigned char BCC = checksum( A, sizeof(A)/sizeof(A[0]) );
 	unsigned char CMD[] = { STX, DADD, 0x03, CMD_GET_SNR, 0x26, 0x00, BCC, ETX };
 	RDM880.write( CMD, sizeof(CMD)/sizeof(CMD[0]) );


	// prepare data to be written
	unsigned char timeByte0 = time & MSB;
	unsigned char timeByte1 = (time >> 4) & MSB;
	unsigned char timeByte2 = (time >> 8) & MSB;
	unsigned char timeByte3 = (time >> 12) & MSB;

	unsigned char A[] = { 0x00, 0x1A, CMD_WRITE, 0x01, numBlocks, startAddress,
						0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,


	// Scan for RFID tags
	while(responseFlag == false) {
		MF_SNR();
		delay(200);
		// getResponse determines if the response packet is OK
		responseFlag = getResponse();
