NFC for embedded
applications
Your critical link for the Internet of Things
NFC—your critical link for the
Internet of Things
Home automation
Tap your phone to
adjust settings for
commissioning
Cloud-based applications
Mobile banking
Social networks
Authentication
App stores analytics
Smart meters
Tap your phone to read
out consumption data
Appliances
Tap your phone for
service diagnostics
or settings
Healthcare
Tap your phone to
read and upload
vital measurements
Consumer electronics
Tap your phone to pair
BT, WiFi, or stream media
Experts predict an explosion of connected
“things” to occur over the next few years.
As more things get connected, concerns
over data privacy and security will escalate.
Utilizing Near Field Communication (NFC) as a
communication method can help address some
of these concerns.
NFC is the critical link
According to market research, soon more users
will access the Internet wirelessly via mobile
devices than from wired Ethernet connections.
These mobile devices offer several different
wireless connectivity options, each with their
different strengths and capabilities. But only
NFC is specifically designed and engineered
to provide zero power operation and maximize
privacy, both at a very low cost.
Privacy
NFC by design has a limited field of operation,
which prevents data snooping that could occur
from a distance. It also requires intent—the
application of an NFC-enabled device to
an NFC-enabled object—in order to read
its memory. This approach is in contrast to
protocols such as WiFi, which require radios to
broadcast information regardless of intent. The
limited field plus other features of the protocol
help to ensure that data exchange only occurs
with the intended party.
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NXP NFC for embedded applications
Low power
When communicating between an NFC reader and
an NFC transponder (tag), energy harvested from
the RF field of the reader powers the tag, enabling
connectivity for Internet of Things (IoT) devices
without using batteries or power. This energy
harvesting feature enables a number of low-power
and low-cost applications.
Low cost
Adding a connected NFC tag to an embedded
system can establish connectivity to mobile
devices at much lower cost than Bluetooth or WiFi
approaches. In addition, eliminating the need for a
battery in an embedded system can further lower an
application’s overall bill of materials.
Comparing wireless protocols
Designers have several choices for connectivity,
all with trade-offs (see Table 1). WiFi, ZigBee,
and Bluetooth all have different strengths and
capabilities. None, however, were specifically defined
and engineered to provide zero-power operation
and maximize privacy, and do both at very low cost,
as NFC does.
Table 1 Wireless connectivity tradeoffs
WiFi
ZigBee (802.15.4)
Bluetooth
NFC
Network topology
Star
Mesh
Point-to-point
Point-to-point
Range
30-100 m
10-20 m
10 m
< 0.1 m
Discovery
Broadcast
Broadcast
Broadcast
Response to field
Power
High
Low
Classic: Mid
Tag: Zero
LE/Smart: Low
Reader: Very low
Privacy
Low
Mid
Mid
High
NXP NFC for embedded applications
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NFC principles of operation
Overview
Near Field Communication (NFC) is
a short-range, wireless connectivity
technology designed to be intuitive.
NFC enables simplified transactions,
data exchange, pairing, wireless
connections, and convenience
between two objects when in
close proximity to one another
(up to 10 cm apart). Because the
communication is one-to-one and
requires such close proximity, data
privacy is more inherent than with
other wireless approaches.
NFC has three communication
modes: Read/Write, Peer-to-Peer,
and Card Emulation.
Read/Write mode
In Read/Write mode, an NFC
reader/writer (or NFC-enabled
mobile phone acting as a traditional
contactless reader/writer) reads data
from NFC-enabled smart objects
and acts upon that information.
With an NFC-enabled phone, for
example, users can automatically
connect to websites via a retrieved
URL, send short message service
(SMS) texts without typing, obtain
coupons, etc., all with only a touch
of their device to the object.
Peer-to-Peer mode
In Peer-to-Peer mode, any
NFC-enabled reader/writer can
communicate to another NFC
reader/writer to exchange data
with the same advantages of
safety, security, intuitiveness, and
simplicity inherent in Read/Write
mode. In Peer-to-Peer mode, one
of the reader/writers behaves as a
tag, creating a communication link.
For example, two devices (such as
smartphones) with readers/writers
can communicate with each other.
Card Emulation mode
An NFC device in Card Emulation
mode can replace a contactless
smartcard, enabling use of NFC-
enabled devices within the existing
contactless card infrastructure
for operations such as ticketing,
access control, transit, tollgates,
and contactless payments. NXP has
broad product offerings to support
the secure transactions necessary for
this mode.
ead/Write
mo
CR
de
NF
Figure 1. The three modes of NFC communication
P
o-
r-t
N
FC
Pee
ee
rm
ode
Em
rd
NFC
Ca
4
NXP NFC for embedded applications
la
u
to
rm
ode
NFC Read/Write mode for
embedded systems
Most embedded applications that
utilize NFC will use Read/Write
mode for the link. In these cases,
an NFC-enabled device, such as
a mobile device, will provide the
active reader, and the tag will be in
the embedded system.
Functionally, a connected NFC tag
in an embedded system behaves
similarly to a dual port memory. One
of the memory ports is accessed
wirelessly through an NFC interface.
The other port is accessed by the
embedded system via an I
2
C interface.
Through this functionality, data can
pass from an external source (e.g.,
an NFC-enabled mobile device) to
the embedded system. Furthermore,
because NFC connected tags are
passive, they can be read from, or
written to, by the external source
even when the embedded system is
powered off.
Because NFC connected tags function
similarly to dual port memories, they
facilitate any application that requires
data transfer between an embedded
system and an external system with an
NFC reader/writer, such as an NFC-
enabled mobile device.
NFC-
enabled
device
I
2
C
NFC
Interface
Memory
I
2
C
Interface
0
1
0
1
0
Microcontroller
Control
Field detect
NFC connected tag
Figure 2. NFC connected tag block diagram
NXP NFC for embedded applications
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