SLOA227B October 2015 – March 2019 TRF7964A , TRF7964A , TRF7970A , TRF7970A
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NFC/HF RFID reader/writer using the TRF7970A
- Trademarks
- 1 Terms, Definitions, and Symbols
- 2 Introduction
- 3 Initial RF Collision
- 4 TRF7970A Register Settings
- 5 Reader/Writer Mode
- 6 Hardware Description
- 7 Reader/Writer Firmware Example
- 8 Quick Start Guide
- 9 Operational Overview
- 10 Reader/Writer Interoperability Results
- 11 Conclusion
- 12 References
- Revision History
5.2.2.3 Attribute Information Block
The format for the Attribute Information Block (see Figure 18) is specified in the NFC Forum Type 3 Tag Operation Specification. Version 1.2 was used to write this application report.
Figure 18. Type 3 Tag Attribute Information Block Format - Mapping Version (Byte 0): For NDEF format it is required that this is set to a valid version number.
- Max Blocks to Read (Byte 1): This value indicates how many blocks of data can be read from the tag at one time.
- Max Blocks to Write (Byte 2): This value indicates how many blocks of data can be written to the tag at one time.
- Blocks for NDEF Storage (Bytes 3 and 4): These bytes indicate the number of blocks available for NDEF content. Since each block is 16 bytes, this value should be multiplied by 16 to know how big the tag is in bytes.
- Unused (Bytes 5-8): These bytes are not used, and typically are set to 0x00.
- Write Flag (Byte 9): This flag is toggled when data is being written to the tag to indicate that the tag is currently in a write cycle.
- NDEF Access Read/Write Flag (Byte 10): This flag is used to indicate the Read/Write privileges of the tag. A value of 0x00 means that the tag is Read Only, and a value of 0x01 means that the tag is Read/Write available.
- Current NDEF Message Length (Bytes 11-13): These bytes indicate the size of the NDEF message that is stored in bytes. Since this value is stored in bytes, it must be divided by 16 to determine how many blocks must be read to receive the full NDEF message.
- Checksum (Bytes 14-15): This is used to verify the validity of the data in the Attribute block, and it is calculated by adding together the values of Bytes 0 through 13. (modified when written to)