AS3956 datasheet(44/109 Pages) AMSCO

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[v1-10] 2018-Apr-27

AS3956 − Detailed Description

32 Byte Buffer

The AS3956 has an internal 32-byte buffer used to:

• Temporarily hold the values of the UID, SENSR1, SENSR2,

SELR which are copied from EEPROM and are used during

anti-collision

• Store data received via RF

• For data exchange between an NFC device and an MCU

connected to the AS3956

The buffer has a position pointer which is set automatically after

each successful write, read or clear operation and points to the

last byte of the data available for read/transmit.

AS3956 Communication Modes

AS3956 supports three different modes. The basic

communication mode is a standalone mode where AS3956 can

behave as a standalone NFC tag without MCU intervention. The

other two modes (Tunneling and Extended mode) represent

modification of the communication in SELECTED state. The

anti-collision process is the same for all three modes.

It is possible to change the mode of operation at any time.

In case Tunneling and Extended mode are both enabled,

Tunneling mode has priority over Extended mode.

Standalone NFC Type 2 Tag Mode

If neither of the two modes are enabled (Tunneling and

Extended mode) in IC Configuration Register 2, the tag is in

standalone mode. In this mode, all RF incoming commands

address the internal EEPROM. In this mode, it is always possible

to connect the MCU since all other functionalities of AS3956 are

not limited by the communication modes. The main purpose of

this mode is to use the AS3956 as a standalone chip or a chip

in combination with MCU where the MCU is used for managing

AS3956 configuration and memory content.

AS3956 Datasheet(PDF) 44 Page - ams AG