NFC Technical Knowledge

NFC technology evolved from contactless radio frequency identification (RFID). The transmission range of RFID can reach several meters or even tens of meters, and can only realize information reading and determination, while NFC technology emphasizes information interaction. Near field communication works at 13.56MHz frequency and runs within 20 cm distance, and its transmission speed is 106Kbit/sec, 212Kbit/sec or 424Kbit/sec.

?? Near Field Communication Forum defines three modes of operation (PDF):

?? Point-to-point mode (P2P mode): Supports mutual communication between two near field communication devices to realize information exchange and file sharing.

?? Reader/writer mode: enables near-field energy communication equipment to read relevant information from posters or exhibition information electronic tags.

??Card emulation: Near field communication devices can be like smart cards, allowing users to pay for retail shopping and transportation.

NFC technical knowledge: NFC architecture and related standards?? NFC mobile phone has a built-in NFC chip, which forms part of the RFID module. It can be used as an RFID passive tag to pay for expenses; it can also be used as an RFID reader for data exchange and collection.

?? From the application mode, there are three modes: NFC card simulation, reader/writer, and point-to-point. The card simulation mode is usually called the read mode. The mobile terminal can simulate an ordinary non-contact card to be read by the POS machine. This mode usually inherits the widely used applications, such as bank cards, access control cards, Bus cards, etc., use NFC mobile phones as the carrier and take advantage of the mobile phone’s advantages in network, multimedia, and human-computer interaction. The application scenarios are also similar to the existing methods; the reader mode is usually called the master reading mode, and the mobile terminal can read Take the content of a contactless card or a contactless tag, in this mode, it may inherit the existing applications, for example, use the NFC mobile phone as a POS machine to read the existing bank card, bus card, or NFC Newly defined application scenarios, such as using NFC mobile phones to read NFC-defined labels

The standard data in the sign can realize functions such as electronic business cards, electronic posters, and WIFI connection; the point-to-point mode refers to the direct transmission of data by two mobile terminals within a short distance. This is a new mode defined by NFC, which is compatible with Bluetooth, Compared with WIFI, it has the two characteristics of close range and simple configuration. In theory, any data interaction between two mobile phones can be realized by simple touch, such as calendar synchronization, location sharing, business card exchange and other functions.

??NFC principle

??NFC architecture and related standards

?? The NFC function of the mobile phone terminal is composed 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: NFC chip, which realizes the processing of analog and digital protocols defined by NFC card simulation, reader/writer, and point-to-point mode;

??2. NFC protocol stack: configure the working mode of the NFC chip and implement various standards defined by the NFC Forum;

??3. SE: Security chip, all businesses involving sensitive data and encryption operations (such as bank cards, bus cards) need to be processed by a separate security chip;

??4. SE access API: open the interface to the client to access the SE to realize functions such as balance reading and air recharge;

??5. SE access control: control and authorize SE access to ensure SE security;

??6.??AP access to SE chip: The interface chip when the client accesses the SE through the application processor. The chip will be different when the type of SE is used. For example, when the SIM card is SE, this chip is a Modem. The above-mentioned different modules can be combined to realize different NFC functions, which can be roughly divided into two types: simple NFC and NFC with SE:

Simple NFC refers to an NFC terminal with only NFC Controller and NFC protocol stack. Since it does not have SE, this terminal can only support the NFC reader and point-to-point functions mentioned in the previous blog post, such as business card exchange and tag reading. NFC functions that are not related to security. Due to the simple structure and the native systems above Android 2.3 have already realized these functions, most of the NFC terminals on the market are this kind of simple NFC. Compared with simple NFC, NFC terminals with SE are integrated with a separate security chip SE. In addition to readers and point-to-point modes, it can support security applications introduced in card simulation mode (such as bank cards, bus cards, etc.). The non-contact card swiping on the POS machine can also support the client's access to the SE, and realize the functions of reading the balance of the bank card and bus card stored in the SE, and recharging in the air.more rfid article, please visit rfid system