Introduction to NFC

NFC(Near Field Communication) is a communication mechanism that uses magnetic induction to enable two electronic devices to establish communication by bringing them within 10 cm of each other. There are two modes in an NFC communication:

• NFC Reader:

NFC Reader is usually a electronic device that requires continuous power supply. In the NFC communication, the NFC Reader emits signal to NFC Tag. An NFC Reader can also simulate a NFC Tag. NFC Reader can be found everywhere in our daily life, such as most mid- or high-level smartphones, Easycard readers, …etc.

• NFC Tag:

The NFC Tag normally operates without power supply. It receives the signal emitted by NFC Reader and excites current through the NFC Tag antenna, then it utilizes the current to process data. Some commonly seen NFC Tag includes Easycard, debit card, …etc.   NFC Tag can be further classified to following categories:

• NFC Forum Type 1: These tags are rewritable but can also be locked to be permanently read only. Available memory sizes are between 92 bytes and 2K bytes. Communication Speed with the Type 1 tag is 106 kbit/sec.
• NFC Forum Type 2: The most common NFC tag type, these tags are rewritable but can also be locked to be permanently read only. Available memory sizes are between 48 bytes and 2K bytes. Communication Speed with the Type 2 tag is 106 kbit/sec.
• NFC Forum Type 3: Type 3 tags are pre-configured at manufacture to be either read and re-writable, or read-only. Memory size can be up to 1 MByte. Communication Speed with the Type 3 tag is 212 kbit/sec.
• NFC Forum Type 4: Type 4 tags are pre-configured at manufacture to be either read and re-writable, or read-only. Memory size can be up to 32 KBytes. Communication speed with the tag is 106 kbit/sec.
• Mifare Classic: Mifare Classic is not an NFC forum compliant tag, although reading and writing of the tag is supported by most of the NFC devices.

  The NFC of Ameba is compatible with NFC Forum Type 2. Available memory size is 136 bytes, the first 16 bytes are NFC Tag Header, and latter 120 bytes can be used to deliver data. Please note that the NFC Tag feature of Ameba is simulated, hence it requires continuous power supply to work properly.   The following figure shows the data format: The UID field is for identification of different NFC devices. Each NFC Tag possesses an unique 7-bytes UID. The following figure shows the data exchange format:   NDEF (NFC Data Exchange Format) is the standard NFC data format defined by the NFC forum. For example, when the mobile device receives data from a NFC Tag, the mobile device can process the data according to the NDEF format.   About NXP 203F data format: http://www.nxp.com/documents/data_sheet/NTAG203F.pdf About standard NFC Forum Type 2 data format: http://apps4android.org/nfc-specifications/NFCForum-TS-Type-2-Tag_1.1.pdf About the NDEF format: http://www.eet-china.com/ARTICLES/2006AUG/PDF/NFCForum-TS-NDEF.pdf