Contactless Communication Principles And Scl01X Usage Recommendations; Power Supply; Data Exchange - SCM Microsystems SCL01X Reference Manual

SCL01X R M
EFERENCE
3.5. Contactless communication principles and SCL01X
usage recommendations
SCL01X is a contactless reader
communicate with user tokens.
2
User tokens are made of a contactless
integrated circuit card connected to an
antenna
User tokens can take several form factors:

Credit card sized smart card

Key fob

NFC mobile phone etc...
Communication between SCL01X and user tokens uses magnetic field inductive coupling.
The magnetic field is generated by SCL01X has a carrier frequency of 13.56MHz.

3.5.1. Power supply

When the user token is put in the magnetic field of the reader, its antenna couples with the
reader and an induction current appears in the antenna thus providing power to the integrated
circuit. The generated current is proportional to the magnetic flux going through the antenna of
the user token.

3.5.2. Data exchange

The carrier frequency of the magnetic field is used as a fundamental clock signal for the
communication between the reader and the card. It is also use as a fundamental clock input for
the integrated circuit microprocessor to function.
To send data to the user token the reader modulates the amplitude of the field. There are
several amplitude modulation and data encoding rules defined in ISO/IEC 14443 and ISO/IEC
18092. The reader should refer to those standards for further details.
To answer to the reader, the integrated circuit card of the user token modulates its way of
loading (impedance) the field generated by the reader. Here also further details can be found in
ISO/IEC 14443 and ISO/IEC 18092.
1
In the ISO/IEC 14443 standard, the reader is called the proximity coupling device (PCD)
2
In the ISO/IEC 14443 standard, the user token is called proximity integrated chip card (PICC)
ANUAL
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designed to
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