 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 };
+	unsigned char CMD[] = { STX, 0x00, 0x03, CMD_GET_SNR, 0x26, 0x00, BCC, ETX };
 	RDM880.write( CMD, sizeof(CMD)/sizeof(CMD[0]) );
 }
 

		  i.e. Block 3, 7 and 11 are sector trailers that contain authentication keys.

*/
void MF_WRITE(unsigned char numBlocks, unsigned char startAddress, unsigned long time) {
	int i = 0;

	// prepare data to be written

	// RFID tag detected, read block that contains time data
	digitalWrite(ledPin, HIGH);
	MF_READ(0x01, 0x05);
	delay(50);
	responseFlag = getResponse(readData);
	// Analyze response packet and data
	if(responseFlag == false) 
		Serial.println("Read unsuccesful, please try again");
	else {

	}


	// Get ready to accumulate time
	elapsedTime = accumulator();

	/*// Write time data to card
	MF_WRITE(0x01, 0x05, elapsedTime);
	delay(200);
	responseFlag = getResponse(readData);
	if(responseFlag == false) Serial.println("Unexpected result");
	*/

}

