Datasheet

Product data sheet

COMPANY PUBLIC

Rev. 3.0 — 2 May 2011

196330 5 of 39

NXP Semiconductors

MF1S50yyX

MIFARE Classic 1K - Mainstream contactless smart card IC

8. Functional description

8.1 Block description

The MF1S50yyX chip consists of a 1 kB EEPROM, RF interface and Digital Control Unit.

Energy and data are transferred via an antenna consisting of a coil with a small number of

turns which is directly connected to the MF1S50yyX. No further external components are

necessary. Refer to the document Ref. 1

for details on antenna design.

• RF interface:

– Modulator/demodulator

– Rectifier

– Clock regenerator

– Power-On Reset (POR)

– Voltage regulator

• Anticollision: Multiple cards in the field may be selected and managed in sequence

• Authentication: Preceding any memory operation the authentication procedure

ensures that access to a block is only possible via the two keys specified for each

block

• Control and Arithmetic Logic Unit: Values are stored in a special redundant format and

can be incremented and decremented

• EEPROM interface

• Crypto unit: The CRYPTO1 stream cipher of the MF1S50yyX is used for

authentication and encryption of data exchange.

• EEPROM: 1 kB is organized in 16 sectors of 4 blocks. One block contains 16 bytes.

The last block of each sector is called “trailer”, which contains two secret keys and

programmable access conditions for each block in this sector.

8.2 Communication principle

The commands are initiated by the reader and controlled by the Digital Control Unit of the

MF1S50yyX. The command response is depending on the state of the IC and for memory

operations also on the access conditions valid for the corresponding sector.

8.2.1 Request standard / all

After Power-On Reset (POR) the card answers to a request REQA or wakeup WUPA

command with the answer to request code (see Section 9.4

, ATQA according to ISO/IEC

14443A).

8.2.2 Anticollision loop

In the anticollision loop the identifier of a card is read. If there are several cards in the

operating field of the reader, they can be distinguished by their identifier and one can be

selected (select card) for further transactions. The unselected cards return to the idle state

and wait for a new request command. If the 7-byte UID is used for anticollision and

selection, two cascade levels need to be processes as defined in ISO/IEC 14443-3.