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NFC payment POS card reader

2020-12-04

. What is the NFC
NFC is wireless near field communication technology. It’s developed by Philips and SONY, NFC is a contactless identification and connectivity technology that enables near field wireless communication between mobile devices, consumer electronics, personal computers and smart control tools. NFC provides a simple, touch-sensitive solution that allows consumers to exchange information, access content and services in a simple and intuitive manner.
NFC adopts electromagnetic coupling induction technology. The electromagnetic field frequency is 13.56MHz, and the carrier frequency band is a global band without license. The originating device USES 13.56MHz signal to excite the antenna to generate a magnetic field. Energy is transferred to the target through near-field coupling. The target modulates the magnetic field and returns the data to the originating device to complete communication.

 


. NFC function point introduction
NFC adopts active and passive reading modes, and NFC application modes are divided into three types:
1. NFC card mode (read mode, the mobile terminal can simulate to become a common contactless card and be read by POS machine, which is equivalent to bank card, access control card, bus card, etc., and can also support client access to SE, so as to realize the functions of bank card stored in SE, bus card balance reading, air recharge, etc.).
2. Reader mode (in the master mode, the mobile terminal can read the contents of a contactless card or a contactless tag, which is equivalent to using an NFC mobile phone as a POS device to read bank cards and bus cards, or reading standard data in tags defined by NFC, such as business cards and posters)
3、Point-to-point mode (refers to two mobile phone terminals passing data directly by touching in close proximity)

 


NFC hardware structure with SE function

The NFC function of mobile terminal consists of NFC Controller, NFC protocol stack, SE, SE access API, SE access control and AP access SE chip. Its main functions are as follows:
1. NFC Controller: Implements the processing of analog and digital protocols defined by NFC card simulation, reader and point-to-point mode.
2. NFC protocol stack: Configure the working mode of NFC chip and implement the standards defined by NFC Forum.
3. SE: Security chip. All businesses involving sensitive data and encryption calculation (such as bank card and bus card) need to be processed by a separate security chip.
4. SE access
API: Develop the interface to access SE to the client to achieve balance reading, air recharge and other functions.


5. SE access control: Control and authorize SE access to ensure SE security
6. AP access SE chip: The interface chip used by the client to access SE through the application processor. The chip will be different depending on the type of SE used,If the SIM card is SE, the chip is the modem.
NFC terminal information routing mechanism is different under different mode, working in the NFC terminal in the simulation model, the signal sent by a POS integration NFC Controller forwarded to handle in the SIM card, and when the NFC terminal work in reading and writing device, point to point mode, or mobile phones to read information from the external card will be sent to you by NFC Controller are forwarded to the NFC protocol stack, eventually passed on to the operating system or the client application process.

. NFC standards
1. NFCIP-1(ISO/IEC10892, ECMA340) stipulates the communication mode, modulation mode, encoding, transmission speed, frame structure, initialization process, collision prevention requirements, transmission protocol and so on for NFC equipment.
2. NFCIP-2(ISO/IEC21481, ECMA352), in order to be compatible with the application of non-contact smart card, defined the selection mechanism of NFC communication mode.

 


. NFC Mode Selection (NFCIP-2)


. NFCIP-1 communication mode
1、Active Mode
a、Initiator and Target must generate their own RF fields during communication
b、You can get very fast connection Settings


2. Passive mode
a. Initiator generates rf field and initiates communication
b. Target responds to the instruction of the originating device by means of load modulation
c. Significantly reduce power consumption


. NFCIP-1 modulation coding method
1.The Initiator to Target modulation encoding

 

Active communication mode

Passive communication mode

106Kbps

modulation

ASK 100%

ASK 100%

encoding

Improved Miller encoding

Improved Miller encoding

212Kbps
424Kbps

modulation

ASK 8%-30%

ASK 8%-30%

encoding

Manchester encoding

Manchester encoding

2. The modulation encoding from Target to Initiator

 

Active communication mode

Passive communication mode

106Kbps

modulation

ASK    100%

847KHz subcarrier load modulation

encoding

Improved Miller coding

Manchester encoding

212Kbps
424Kbps

modulation

ASK    8%-30%

847KHz subcarrier load modulation

encoding

Manchester encoding

Manchester encoding

. NFC technology features
A. Based on 13.56M RFID technology
B. Close range induction, safe and reliable communication
C. Compatible with existing international standards for contactless smart CARDS
D. Data transmission rates are 106kbit/s, 212kbit/s or 424kbit/s
E. Multiple communication modes switch
F. Fast processing speed
. NFC technology hardware architecture
The hardware architecture of NFC technology includes: NFC simulation front end and security unit
1. NFC simulation front end
a. NFC Controller
b. antenna
2. Security unit
a、SIM card
b、smart card(IC、SAM)
c、SD card

 
. NFC chip and SIM card connection mode
1. SIM card pin definition

2. Available pins
a. C4 and C8: have been extended by the International Standard organization to the new generation of SIM card high-speed interface.
b.C6: VPP high-voltage programming pin, no effect.
3. C4 and C8 schemes
The first NFC solution (NXP) consists of an analog front end and a security chip (Smart MX).
The analog front end and security chip adopt S2C bus interface, develop SIM card based on Smart MX, keep C4 and C8 as S2C interface.


4、SWP(Single Wire Protocol)project

5. Features of SWP scheme.
a. Realize full-duplex communication based on voltage and load on one signal line.
b. SIM card supports 7816 and SWP interface.
c. The SIM card needs to support two interfaces of the protocol stack
d. The two interfaces need to be managed independently
e. SWP scheme requires the redesign of NFC front-end chip and SIM, which involves a wide range of aspects and is difficult to promote in the market.
 
6、CLFI(Contactless Frontend Interface)precept

 
7.Features of CLFI scheme
a. Sony is based on Felica technology
b. CLFI transmits energy on C6 pins in addition to data signal and clock signal
c. The CLFI does not need to connect the VCC (C1) pin of the SIM card, and the SIM card extracts energy directly from the CLFI signal
d. CLFI signal is a half-duplex communication mode through amplitude modulation and load modulation.

. NFC business introduction
1. NFC business definition
"NFC Business" is a service product that takes mobile phones as the carrier, combines contactless IC card application into SIM card, and realizes mobile phone payment, industry application, point exchange, electronic ticketing, identity identification, anti-counterfeiting, advertising and other applications in three application modes: card, reader and point-to-point.

 

2. NFC business model
a. Three types of application patterns

b. Application of classification

Apply

Category

Application of classification

Card mode application

Electronic wallet card applications

bank card

gas filling card

parking card

bus card

Magnetic stripe card application

discount coupon

Magnetic stripe bank card

Ticketing applications

Presumably votes

Air or train tickets
 

Class ID applications

entrance guard

Membership card, credit card

Reader mode application

Tag class application

advertising

information and telephone directory

Point to point mode application

 

information interchange

game

 

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