An introduction to NFC and NFC Data Exchange Format (NDEF)

1. Introduction to NFC
Wei-Tsung Su (蘇維宗)
ellington.su@gmail.com
05/28/2014 (Ver. 1.0)
Page : 1Ubiquitous Computing and Ambient Networking Laboratory

2. Change Log
Date Ver. Authors Description
5/28/2014 1.0 Wei-Tsung Su Introduction to NFC; NFC Data Exchange Format
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3. Reference
• NFC Data Exchange Format (NDEF) Technical
Specification 1.0
• NFC Record Type Definition (RTD) Technical
Specification 1.0
• Text Record Type Definition 1.0
• URI Record Type Definition 1.0
• Smart Poster Record Type Definition 1.1
• http://developer.android.com/guide/topics/connect
ivity/nfc/index.html
• http://nfc-forum.org/
• http://www.nfc.cc/
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4. Near Field Communication (NFC)
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5. Introduction to NFC
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6. NFC
• NFC is a contactless communication
– In typical, the communication distance is less than 4 cm
– Operation frequency is 13.56MHz
– Killer applications: e-wallet, name card exchange, check-in, and so on
– Related standards
• NFCIP-1 (ISO 18092 or ECMA 340)
• NFCIP-2 (ISO 21481 or ECMA 352)
• NFC Operation Mode
– Peer-to-Peer
– Reader/Writer
– Card Emulation
• NFC Tag
– Simple: typically write-once
– Complex: provide mathematical operations, hardware encryption
– Sophisticated: provide computation environment
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7. NFC Operation Modes
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8. NFC Protocol Stack
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9. NFC Forum Tag Type
• Type 1 (based on ISO 14443-A)
– Re-writable / write-protection
– Memory size is between 96
bytes and 2 Kbytes
– Speed: 106 Kbps
– Vendor: Topaz (Broadcom)
• Type 2 (based on ISO 14443-A)
– Re-writable / write-protection
– Memory size is between 48
bytes and 2 Kbytes
– Speed: 106 Kbps
– Vendor: NXP
• Type 3 (based on JIS 6319-4,
as known as FeliCa)
– Pre-configured as re-writable or
read-only
– Memory size is limited to 1
Mbytes
– Speed: 212/424 Kbps
– Vendor: Sony
• Type 4 (compliant with ISO
14443-A/B series)
– Pre-configured as re-writable or
read-only
– Memory size is limited to 32
Kbytes
– Speed: 212/424 Kbps
– Vendor: NXP
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10. NFC Data Exchange Format (NDEF)
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11. NFC Data Exchange Format (NDEF)
• NDEF Message Format
• Description
– Each NDEF message is composed of multiple NDEF records (unbounded
but limited by memory size)
– Each NDEF record can carry the data with size of 232-1 bytes
• If there is multiple NDEF records, the flag of message begin (MB) must be set as 1
in the first NDEF record.
• If there is multiple NDEF records, the flag of message end (ME) must be set as 1 in
the last NDEG record.
• If there is only on NDEF records the flags of MB and ME must be set as 1 in the
NDEG record.
– NDEF does not provide error handling, QoS, and other additional
functionalities.
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NDEF Message
NDEF Record 1
(MB=1)
NDEF Record 2
…
NDEF Record n
(ME=1)

12. NDEF Record
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• Flags
– Message Begin (MB)
– Message End (ME)
– Chunk Flag (CF)
– Short Record (SR)
– ID Length (IL)
• Type Name Format (TNF)
– Indicates the data type
– Indicates how to read Type filed
• Type Length
• ID Length
• Payload Length
• Type
– Indicates payload type
• ID (not tag ID)
– Unique NDEF Message ID
• Payload
– Actual data
7 6 5 4 3 2 1 0
MB ME CF SR IL TNF
Type Length
Payload Length 3
Payload Length 2
Payload Length 1
Payload Length 0
ID Length
Type
ID
Payload

13. Short NDEF Record
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7 6 5 4 3 2 1 0
MB ME CF SR = 1 IL TNF
Type Length
Payload Length
ID Length
Type
ID
Payload

14. Type Name Format (TNF)
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• Record Type Definition (RTD) in NFC Forum well-known type
– Text
– URL
– Smart Post
Type Name Format Value
Empty 0x00
NFC Forum well-known type [NFC RTD; RFC 2141] 0x01
Media-type as defined in RFC 2046 [RFC 2046] 0x02
Absolute URI as defined in RFC 3968 [RFC 3968] 0x03
NFC Forum external type [NFC RTD] 0x04
Unknown 0x05
Unchanged 0x06
Reserved 0x07

15. • NDEF record example of Text RTD
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7 6 5 4 3 2 1 0
MB ME CF SR IL TNF = 0x01
Type Length = 0x01
Payload Length 3
Payload Length 2
Payload Length 1
Payload Length 0
ID Length
Type = “T”
ID
Payload
TNF: NFC Forum Well-known Type
Text RTD

16. TNF: NFC Forum Well-known Typecon’t
Text RTD
• Payload Structure
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RTD Text Payload
0 1 … n n+1 … m
Status
byte
IANA Language Code
(Encoded by US-ASCII)
Text
(Encoded by UTF-8 or UTF-16
depending on status bit)
Status byte
0 1 2 3 4 5 6 7
0: UTF-8
1: UTD16
0 The length of the IANA language code.

17. TNF: NFC Forum Well-known Type
URI Service RTD
• NDEF record example of URI service RTD
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7 6 5 4 3 2 1 0
MB ME CF SR IL TNF = 0x01
Type Length = 0x01
Payload Length 3
Payload Length 2
Payload Length 1
Payload Length 0
ID Length
Type = “U”
ID
Payload

18. TNF: NFC Forum Well-known Typecon’t
URI Service RTD
• Payload Structure
• ID Code
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RTD URI Payload
0 1 … n
URI
ID code
URI field encoded by UTF-8
(The rest of the URI, or the entire URI if ID code is 0x00)
Hex. URL Prefix Hex. URL Prefix Hex. URL Prefix Hex. URL Prefix
0x00 N/A 0x0A sftps:// 0x14 pop: 0x1E urn:epc:id:
0x01 http://www. 0x0B smb:// 0x15 sip: 0x1F urn:epc:tag:
0x02 https://www. 0x0C nfs:// 0x16 sips 0x20 urn:epc:pat
0x03 http:// 0x0D ftp:// 0x17 tftp: 0x21 urn:epc:raw
0x04 https:// 0x0E dav:// 0x18 btspp:// 0x22 urn:epc:
0x05 tel: 0x0F news:// 0x19 btl2cap:// 0x23 urn:nfc
0x06 mailto: 0x10 telnet:// 0x1A btgoep:// … Reserved
0x07 ftp://anonymous:anonymous@ 0x11 imap 0x1B tcpobex://
0x08 ftp://ftp. 0x12 rtsp:// 0x1C irdaobex://
0x09 ftps:// 0x13 urn:// 0x1D dile://

19. TNF: NFC Forum Well-known Type
Smart Post RTD – URL, SMS, Phone Number
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• NDEF record example of Smart Post RTD
7 6 5 4 3 2 1 0
MB ME CF SR IL TNF = 0x01
Type Length = 0x02
Payload Length 3
Payload Length 2
Payload Length 1
Payload Length 0
ID Length
Type = “Sp”
ID
Payload

20. TNF: NFC Forum Well-known Typecon’t
Smart Post RTD – URL, SMS, Phone Number
• The payload of Smart Post RTD is an NDEF message which is composed
of multiple following specific NDEF records
– URI record
• The core of Smart Poster.
• MUST have one and only one URI record
– Title record
• COULD have multiple title records with different languages
– Action record
• Used to provide the recommendation of processing this service
– Icon record
– Size record
• If URI record indicates a external entity, the size record which indicates the size of
external entity to make sure the device is capable of handling this external entity.
– Type record
• If URI record indicates a external entity, the type record is used to indicates the
MIME type of this external entity.
– Application-specific record
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21. Q & A
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