ib technology

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Mifare Ultralight (64 byte) Memory Map

Note: Ultralight card has 7 byte serial number (+ 2 check bytes)

Bcc0 = CT xor Sn0 xor Sn1 xor SN2 (CT = Cascade Tag = 0x88)

Bcc1 = Sn3 xor Sn4 xor Sn5 xor Sn6

The Mifare Ultralight transponder has a different structure to the standard 1k and 4k

byte Mifare transponders. The 64 byte memory is organised as sixteen pages of four bytes

each. The first two pages (and byte 0 of page 3) contain a seven byte serial number (UID)

together with two check bytes. The other “system” bytes are used for locking card features

and providing a number of OTP (One Time Programmable) data bytes. The remaining 12

pages (48 bytes) can be used for general read/write storage.

Despite having a different memory structure, the Ultralight uses the same Mifare

communication protocol except that a cascaded selection procedure is used and the

Authentication procedure is not used for read/write operations. The security Keys are

therefore NOT required for any operations to an Ultralight card. Because of it’s smaller

memory, more basic operation and lower cost, the Ultralight card is typically used for low-

value single applications.

The MicroRWD MF reader module fully supports the Ultralight cards and the read and write

commands have the same format as for the standard cards except that dummy data bytes

(0x00 values) are used for the Key number etc. In addition the “block number” argument

becomes a “page number” parameter.

Sn0

Sn1

Sn2

Bcc0

Sn3

Sn4

Sn5

Sn6

Bcc1

Int

Lock0

Lock1

OTP0

OTP1

OTP2

OTP3

32 bit Data

32 bit Data

32 bit Data

32 bit Data

32 bit Data

32 bit Data

32 bit Data

32 bit Data

32 bit Data

32 bit Data

32 bit Data

32 bit Data

(12 pages)

48 bytes

Read/Write

Data

4 byte Page

Byte 0

Byte 3

Page 0 (0x00), Serial number

16 Pages

(4 bytes each)

Page 15 (0x0F)

Page 3 (0x03), One Time Program

Page 1 (0x01), Serial number

Page 2 (0x02), Internal/Lock