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MAX66120

ISO 15693-Compliant 1Kb Memory Fob

6 _______________________________________________________________________________________

ISO 15693 Communication

Concept

The communication between the master and the

MAX66120 (slave) is based on the exchange of data

packets. The master initiates every transaction; only

one side (master or slaves) transmits information at any

time. Each data packet begins with a start-of-frame

(SOF) pattern and ends with an end-of-frame (EOF)

pattern. A data packet with at least 3 bytes between

SOF and EOF is called a frame (Figure 5). The last 2

bytes of an ISO 15693 frame are an inverted 16-bit

CRC of the preceding data generated according to the

CRC-16-CCITT polynomial. This CRC is transmitted with

the LSB first. For more details on the CRC-16-CCITT,

refer to ISO 15693 Part 3, Annex C.

For transmission, the frame information is modulated on

a carrier frequency, which is 13.56MHz for ISO 15693.

The subsequent paragraphs are a concise description

of the required modulation and coding. For full details

including graphics of the data coding schemes and

SOF/EOF timing, refer to ISO 15693-2, Sections 7.2,

7.3, and 8.

CODE DESCRIPTION

00000000b

(00h)

Unlocked (factory default)

10101010b

(AAh)

Locked (irreversible)

All other codes Unlocked

Table 3. Protection Code Assignments for U-Lock, AFI-Lock, DSFID-Lock, S-Lock

SOF 1 OR MORE DATA BYTES CRC (LSB) CRC (MSB) EOF

TIME

Figure 5. ISO 15693 Frame Format

Figure 6. Downlink Modulation (e.g., Approximately 100% Amplitude Modulation)

CARRIER

AMPLITUDE

100%

1 2 3 4 5 6 7 8 9 10 11 ... 23 24

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