//   COMMENT: This functions reads out data stored in the MF RC500's EERPOM   
//	      beginning ataddress startaddr. The number of bytes to be read are  
//	      given by  the variablelength and the read out data are stored in  
//            the provided data buffer.
//
char PcdReadE2(unsigned short startaddr,  
               unsigned char length,
               unsigned char* _data);

// _____________________________________________________________________________
//
//  FUNCTION: PcdWriteE2
//        IN: startaddr     2 bytes of starting address of the E2PROM 
//            length        number of byte of data to be write
//       OUT: *_data        buffer for the write bytes 
//    RETURN: 
//   COMMENT: This function writes a given length of data bytes stored in the data  
// 	      buffer to the reader IC's EEPROM beginning at address <em>startaddr</em>. 
//
char PcdWriteE2(unsigned short startaddr,
                unsigned char length,
                unsigned char* _data);

// _____________________________________________________________________________
//
//  FUNCTION: M500PcdMfOutSelect
//        IN: type      The signal to be appear at MfOut pin 
//
//		000: Constant Low
//		001: Constant High
//		010: Modulation signal from the internal coder, Miller coded
//		011: Serial data stream, not Miller coded
//		100: Output signal of the energy carrier demodulator
//		101: Output signal of the subcarrier demodulator
//		110: RFU
//		111: RFU
//       OUT: -
//    RETURN: 
//   COMMENT: This function config the output of the MfOut pin
//                     
char M500PcdMfOutSelect(unsigned char type);
                     
// _____________________________________________________________________________
//
//  FUNCTION: M500PcdWriteRegister
//        IN: Reg      	Register address
//	      value	value to be written	 
//       OUT: -
//    RETURN: 
//   COMMENT: This function write the value to the RC500 register
//                     
char M500PcdWriteRegister(unsigned char Reg, unsigned char value);

// _____________________________________________________________________________
//
//  FUNCTION: M500PcdReadRegister
//        IN: Reg      	Register address 
//       OUT: -
//    RETURN: value	value of register
//   COMMENT: This function read the value of the RC500 register
//                     
char M500PcdReadRegister(unsigned char Reg);

// _____________________________________________________________________________
//
//  FUNCTION: M500PiccRequest
//        IN: rq_code  can take the following values
//                     ALL   Request Code 52hex is sent out to get also a 
//                           response from cards in halt state.
//                     IDLE  Request Code 26hex is sent out to get a response 
//                           only from cards that are not in halt state.
//                     Note: Future cards will work also with other request 
//                           codes.
//       OUT: atq      16 bit ATQ (answer to request). 
//                     atq[0] .. LSByte
//                     atq[1] .. MSByte
//    RETURN: 
//   COMMENT: This function accesses the reader module and activates sending the
//            REQ code to the MIFARE card. After sending the command to the card 
//            the function waits for the card's answer.
//
//            Please note, that the actual work is done by the function
//            M500PiccCommonRequest, because of the interface behaviour between
//            Mifare and ISO 14443
//
//            The Card replies the ATQ.
//
//            ATQ:
//
//                    +----+----+----+----+----+----+----+----+
//            LSByte  | b8 | b7 | b6 | b5 | b4 | b3 | b2 | b1 |
//                    +----+----+----+----+----+----+----+----+
//                    |         |    |                        |
//                    | UID size| RFU|   bit-frame anticoll   |
//                    |         |    |                        |
//                    | 00..std |    |  (if any bit set .. Y, |
//                    | 01..dbl |    |             else .. N) |
//                    | 10..tpl |    |                        |
//
//
//
//                    +----+----+----+----+----+----+----+----+
//            MSByte  | b8 | b7 | b6 | b5 | b4 | b3 | b2 | b1 |
//                    +----+----+----+----+----+----+----+----+
//                    |                                       |
//                    |                 RFU                   |
//                    |                                       |
//
char M500PiccRequest(unsigned char req_code, 
                       unsigned char *atq);
// _____________________________________________________________________________
//
//  FUNCTION: M500PiccCommonRequest
//        IN: rq_code  can take the following values
//                     ALL   Request Code 52hex is sent out to get also a 
//                           response from cards in halt state.
//                     IDLE  Request Code 26hex is sent out to get a response 
//                           only from cards that are not in halt state.
//                     Note: Future cards will work also with other request 
//                           codes.
//       OUT: atq      16 bit ATQ (answer to request). 
//                     atq[0] .. LSByte
//                     atq[1] .. MSByte
//    RETURN: 
//   COMMENT: Please note, that this function does the actual work which is 
//            described in function M500PiccRequest.
//
char M500PiccCommonRequest(unsigned char req_code, 
                             unsigned char *atq);  

// _____________________________________________________________________________
//
//  FUNCTION: M500PiccAnticoll
//        IN: bcnt       Number of snr-bits that are known (default value is 0)
//            *snr       4 bytes serial number (number of bits, which
//                       are known and indicated by "bcnt"
//       OUT: *snr       4 bytes serial number, determined by the anticollision
//                       sequence
//    RETURN: 
//   COMMENT: The actual anticollision loop is done by the function
//            "M500PiccCascAnticoll". Which is called with select_code 0x93.
//
char M500PiccAnticoll (unsigned char bcnt,
                         unsigned char *snr);

// _____________________________________________________________________________
//
//  FUNCTION: M500PiccCascAnticoll
//        IN: select_code    0x93  standard select code
//                           0x95  cascaded level 1
//                           0x97  cascaded level 2
//            bcnt       Number of snr-bits that are known (default value is 0)
//            *snr       4 bytes serial number (number of bits, which
//                       are known and indicated by "bcnt"
//       OUT: *snr       4 bytes serial number, determined by the anticollision
//                       sequence
//    RETURN: 
//   COMMENT: Corresponding to the specification in ISO 14443, this function
//            is able to handle extended serial numbers. Therefore more than
//            one select_code is possible. The function transmitts a 
//            select code and all ready tags are responding. The highest
//            serial number within all responding tags will be returned by 
//            this function.
//                     
char M500PiccCascAnticoll (unsigned char select_code,
                             unsigned char bcnt,
                             unsigned char *snr);                     

// _____________________________________________________________________________
//
//  FUNCTION: M500PiccSelect
//        IN: *snr      4 bytes serial number
//       OUT: *sak      1 byte select acknowledge
//			xxxxx1xx: Cascade bit set: UID not complete
//			xx1xx0xx: UID complete,
//				  PICC compliant with ISO/IEC 14443-4
//			xx0xx0xx: UID complete,
//				  PICC not compliant with ISO/IEC 14443-4
//    RETURN: 
//   COMMENT: The actual select procedure is done by the function
//            "M500PiccCascSelect". Which is called with select_code 0x93.
//             
char M500PiccSelect(unsigned char *snr, 
                      unsigned char *sak);

// _____________________________________________________________________________
//
//  FUNCTION: M500PiccCascSelect
//        IN: select_code 
//            *snr          4 bytes serial number
//       OUT: *sak          1 byte select acknowledge
//    RETURN: 
//   COMMENT: Selects a UID level, depending on select code.
//            Returns Select Acknowledge byte.
//
//            Corresponding to the specification in ISO 14443, this function
//            is able to handle extended serial numbers. Therefore more than
//            one select_code is possible.
//
//            Select codes:
//
//            +----+----+----+----+----+----+----+----+
//            | b8 | b7 | b6 | b5 | b4 | b3 | b2 | b1 |
//            +-|--+-|--+-|--+-|--+----+----+----+-|--+
//              |    |    |    |  |              | |
//                                |              |
//              1    0    0    1  | 001..std     | 1..bit frame anticoll
//                                | 010..double  |
//                                | 011..triple  |
//
//            SAK:
//
//            +----+----+----+----+----+----+----+----+
//            | b8 | b7 | b6 | b5 | b4 | b3 | b2 | b1 |
//            +-|--+-|--+-|--+-|--+-|--+-|--+-|--+-|--+
//              |    |    |    |    |    |    |    |
//                        |              |
//                RFU     |      RFU     |      RFU
//
//                        1              0 .. UID complete, ATS available
//                        0              0 .. UID complete, ATS not available
//                        X              1 .. UID not complete
//
char M500PiccCascSelect(unsigned char select_code, 
                            unsigned char *snr, 
                            unsigned char *sak); 

// _____________________________________________________________________________
//
//  FUNCTION: MfPiccAuth
//        IN: auth_mode PICC_AUTHENT1A or PICC_AUTHENT1B 
//                            selects master key A or master key B 
//                      KS0, KS1, KS2 selects one of the three master key sets.
//            *snr       4 byte serial number of the card, which should be 
//                       authenticated
//            key_sector spec. the key RAM address from which the data should be
//                      taken (0..15)
//            block     addresses the block address on the card, which shall be
//                      authenticated. For MIFARE standard cards, addr can take 
//                      a value from 0 to 63, for other card types please refer
//                      to the according product description.
//       OUT: -
//    RETURN: 
//   COMMENT: This function authenticates one card's sector (according to the 
//            block address addr) using the specified mode and master key,