Rainbow Electronics MAX66140 - Manual (Page 5)

ISO 15693 Communication
Concept
The communication between master and MAX66140
(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 in the case of ISO 15693 is
13.56MHz. The subsequent paragraphs are a concise
description of the required modulation and coding. For
MAX66140
ISO 15693-Compliant Secure Memory
_______________________________________________________________________________________ 7
SOF 1 OR MORE DATA BYTES CRC (LSB) CRC (MSB) EOF
TIME
Figure 5. ISO 15693 Frame Format
ABRIDGED DATA SHEET