ST25DV64K datasheet(100/220 Pages) STMICROELECTRONICS

100 / 220 page

RF operations

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DocID027603 Rev 4

Frequency

The ISO 15693 standard defines the carrier frequency (fC) of the operating field as 13.56

MHz ±7 kHz.

7.2

RF communication and energy harvesting

As the current consumption can affect the AC signal delivered by the antenna, RF

communications with ST25DVxxx are not guaranteed during voltage delivery on the energy

harvesting analog output V_EH.

RF communication can disturb and possibly stop Energy Harvesting mode.

7.3

Fast transfer mode mailbox access in RF

Thanks to dedicated commands, the RF interface has the possibility to check Mailbox

availability, and the capability to access it directly to put or get a message from it (see

Section 5.1: Fast transfer mode (FTM) for specific features).

7.4

RF protocol description

7.4.1

Protocol description

The transmission protocol (or simply “the protocol”) defines the mechanism used to

exchange instructions and data between the VCD (Vicinity Coupling Device) and the

ST25DVxxx in both directions. It is based on the concept of “VCD talks first”.

This means that a ST25DVxxx does not start transmitting unless it has received and

properly decoded an instruction sent by the VCD. The protocol is based on an exchange of:

•

a request from the VCD to the ST25DVxxx,

•

a response from the ST25DVxxx to the VCD.

Each request and each response are contained in a frame. The frame are delimited by a

Start of Frame (SOF) and End of Frame (EOF).

The protocol is bit-oriented. The number of bits transmitted in a frame is a multiple of eight

(8), that is an integer number of bytes.

A single-byte field is transmitted least significant bit (LSBit) first. A multiple-byte field is

transmitted least significant byte (LSByte) first and each byte is transmitted least significant

bit (LSBit) first.

ST25DV64K Scheda tecnica(PDF) 100 Page - STMicroelectronics