Introduction to nfc

Ray Cheng

Introduction to NFC

Outline

• Introduction to NFC

• Use Cases

• Technical Overview

• NFC on Android

Introduction to NFC

• Near Field Communication

• A short-range radio technology that enables communication between devices that either touch or are momentarily held close together– NFC is an open-platform technology that is being

standardized in the NFC Forum

– NFC is based on and extends on RFID. It operates on 13.56 MHz frequency

– The NFC communication range is up to 10 cm

– The NFC standard supports different data transmission rates such as 106 kBps, 212 kBps, and 424 kBps

RFID

• NFC tag is a simple, thin device containing an antenna and a small amount of memory

• It is a passive device, powered by a magnetic field

• Depending on the tag type, the memory can be – Read only

– Rewritable

– Writable onceIC Antenna

RFID – TAG

• The reader is an active device that generates radio signals to communicate with the tags

• The reader powers the passive device when the two are engaged in the passive mode of communication.

RFID – Reader/ Writer

• NFC devices can operate in three different modes– Read / Write

– Peer to Peer

– Card emulation

• Based on the ISO/IEC 18092, NFC IP-1, and ISO/IEC 14443 contactless smart card standards

Operation Modes

• The NFC-enabled phone can read or write data to any of the supported tag types in a standard NFC data format.

Operation Modes – Read/Write

• In P2P mode, two NFC-enabled devices can exchange data

• Share Bluetooth or Wi-Fi link setup parameters to initiate a Bluetooth or Wi-Fi link

• Exchange data such as virtual business cards or digital photos

• Based on the ISO/IEC 18092 standard.

Operation Modes – Peer to Peer

• In Card emulation mode, the phone can act as a tag or contactless card for existing readers.

Operation Modes – Card Emulation

• Introduction to NFC

• Use Cases

• Technical Overview

• NFC on Android

Outline

Use Cases

Use Cases

Use Cases

Use Cases

Use Cases

• Introduction to NFC

• Use Cases

• Technical Overview

• NFC on Android

Outline

• NFC Tag Types

• Transition Specs

• NFC Data Exchange Format (NDEF)

Technological Overview

• NFC Forum tag types– Type 1 tag

– Type 2 tag

– Type 3 tag

– Type 4 tag

• NXP-specific tag type– Type MIFARE Classic Tag

Tag Types

• Type 1 Tags are cost effective and ideal for many NFC applications– Based on ISO-14443A standard

– Read and rewrite capable; also users can configure the tag to be read-only

– 96 bytes of memory, expandable up to 2 kB

– Communication speed 106 kbits/s

– No data collision protection

Type 1 Tag

• Type 2 Tags are similar to Type 1 Tags and are derived from the NXP/Philips MIFARE Ultralight tag– Based on ISO-14443A standard

– Read and rewrite capable; also users can configure the tag to be read-only

– 96 bytes of memory, expandable up to 2 kB

– Communication speed 106 kbits/s

– Anti-collision support

Type 2 Tag

• Type 3 Tags are derived from the nonsecure parts of Sony FeliCa tags. These tags are more expensive than Types 1 and 2– Based on the Japanese Industrial Standard (JIS) X 6319-4

– Preconfigured at manufacture to be either read and rewritable, or read-only

– Variable memory, up to 1 MB per service

– Supports two communication speeds: 212 or 424 kbits/s

– Anti-collision support

Type 3 Tag

• Type 4 Tags are similar to Type 1 Tags and are derived from the NXP DESFire tag– Based on ISO-14443A standard

– Preconfigured at manufacture to be either read and rewritable, or read-only

– Variable memory, up to 32 kB per service

– Supports three different communication speeds: 106, 212, or 424 kbits/s

– Anti-collision support

Type 4 Tag

• This is a proprietary tag type defined by NXP Semiconductors– Based on ISO-14443A standard

– Read and rewrite capable; also users can configure the tag to be read-only

– Variable memory 192/768/3584 bytes

– Communication speed 106 kbits/s

– Anti-collision support

Type MIFARE Classic Tag

• ISO-14443

• NFCIP-1

• MIFARE

• FeliCa

NFC Relative Specifications

• ISO 14443 is a well-known international standard originally developed for contactless chip card communication over a 13.56 MHz radio.

• ISO 14443 defines a protocol stack from the radio layer up to a command protocol.

ISO 14443

• Peer-to-peer communication between two NFC devices is made possible by mechanisms defined in the Near Field Communication - Interface and Protocol Specification, NFCIP-1, also known as ISO 18092 and ECMA-340

• NFCIP-1 includes two communication modes that allow an NFC device to communicate with other NFC devices in a peer-to-peer manner, as well as with NFCIP-1 based NFC tags

NFCIP-1

• MIFARE refers to an NFC tag type developed by NXP Semiconductors

• MIFARE tags are widely used as memory cards in transportation applications

MIFARE

• FeliCa is a proprietary NFC tag technology developed by Sony, and it is widely used in proprietary payment and transportation applications in the Asian markets

• FeliCa tags are standardized as a Japanese industry standard. The tags are based on the passive mode of ISO 18092, with added authentication and encryption capabilities.

FeliCa

• The NFC Data Exchange Format (NDEF) specification defines a message encapsulation format to exchange information

NDEF

NDEF

NDEF

NDEF

NDEF

NDEF

• Introduction to NFC

• Use Cases

• Technical Overview

• NFC on Android

Outline

• When a Android Device being engaged with another NFC device, the tag dispatch system start to work

• Tag dispatch system retrieve data from another NFC device and decide what to do according to the data

• Work closely with Android Intent and Intent Filter

NFC on Android

TagDispatchSystem

Intent

NDEFNDEF

Activity 1

<Intent Filter>

Activity 2

<Intent Filter>

Activity N

<Intent Filter>

…generate

NFC – Read/Write

• ACTION_NDEF_DISCOVERED: This intent is used to start an Activity when a tag that contains an NDEF payload is scanned and is of a recognized type. This is the highest priority intent, and the tag dispatch system tries to start an Activity with this intent before any other intent, whenever possible.

• ACTION_TECH_DISCOVERED: If no activities register to handle the ACTION_NDEF_DISCOVERED intent, the tag dispatch system tries to start an application with this intent. This intent is also directly started (without starting ACTION_NDEF_DISCOVERED first) if the tag that is scanned contains NDEF data that cannot be mapped to a MIME type or URI, or if the tag does not contain NDEF data but is of a known tag technology.

• ACTION_TAG_DISCOVERED: This intent is started if no activities handle the ACTION_NDEF_DISCOVERED or ACTION_TECH_DISCOVERED intents

Tag Dispatch System

Tag Dispatch System

Tag Dispatch System

Tag Dispatch System

• The following example filters for ACTION_NDEF_DISCOVERED intents with a MIME type of text/plain:

• The following example filters for a URI in the form of http://developer.android.com/index.html

ACTION_NDEF_DISCOVERED

• This example illustrates how to retrieve NDEF message from an Intent

Obtaining Information from Intents

• This example encapsulate a NDEF record with URI information

• The following is the corresponding intent filter

Obtaining Information from Intents – Absolute URI

• This example encapsulate a NDEF record with MIME information

• The following is equivalent to the upper example

• The following is the corresponding intent filter

Obtaining Information from Intents – MIME Media

• This example encapsulate a NDEF record with MIME type text/plain data

• The following is the corresponding intent filter

TNF_WELL_KNOWN_with RTD_TEXT

• This example encapsulate a NDEF record with URI data

• The following is the corresponding intent filter

TNF_WELL_KNOWN_with RTD_URI

• This example encapsulate a NDEF record external data

• The following is the corresponding intent filter

TNF_EXTERNAL_TYPE

• An AAR has the package name of an application embedded inside an NDEF record

• Android searches the entire NDEF message for AARs. If it finds an AAR, it starts the application based on the package name inside the AAR

• If the application is not present on the device, Google Play is launched to download the application

Android Application Records (AAR)

• Introduction to NFC

• Understanding NFC Data Exchange Format (NDEF) messages

• Android NFC Basics

References

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