DocID018867 Rev 4

9/38

AN3408

NDEF data

2

NDEF data

NDEF, which stands for NFC data exchange, is a data format defined by the NFC forum.

This format defines a message encapsulation format to exchange information between a

reader and a contactless tag.

NDEF can be used to exchange different types of information such as text, URI and others.

This chapter details NDEF for the following types of information:

•

text

•

URI

•

vCard, which is a virtual business card

•

Bluetooth, that allows to carry out the pairing between two bluetooth devices.

2.1

Overview

NDEF data is composed of:

•

Capability container

•

TLV field, which includes the NDEF message.

The TLV field is located after the CC field. The size of a TLV field is computed according to

the CC2 byte value.

2.2

Capability container field

The Capability container field (CC field) is a 4-byte field that contains an identification value

used to store an NDEF message. The signification of each byte is explained in Table 7.

Table 7. Capability container field description

Byte name

Byte

number

Value

Bit

Function

CC0

0

0xE1

7:0

NDEF message is present into memory (called magic number)

CC1

1

0xXX

7:6

Major version number

5:4

Minor version number

3:2

Read access condition

1:0

Write access condition

CC2

2

0xXX

7:0

Memory size of data field and CC field in bytes (= CC2 * 8)

CC3

3

0x0X

7:3

RFU

2

1: the IC memory size exceeds 2040 bytes (CC2 overflow)

1RFU

0

1: IC supports ReadMultipleBlocks Command

0: IC does not support ReadMultipleBlocks Command