SLOA208B November 2014 – March 2019 TRF7970A , TRF7970A
The frame format for Data Exchange Protocol (DEP) packets at 106 kbps during anticollision(see Figure 3) is based on NFC-A technology specifications in NFCForum-TS-DigitalProtocol-1.0 or the ISO 14443-3 specifications.
Initially, when configured for Type 4A tag platform emulation, the TRF7970A must be receiving without CRC, because of the ISO 14443A protocol being used. After receiving commands from the reader/writer, the following registers must be modified before and after the anticollision is completed:
or
The ISO control register needs to be modified for the anticollision state to receive without CRC for the required commands (See the TRF7970A data sheet and ISO/IEC 14443-3 specification for more information). When the anticollision is completed, the ISO Control register needs to be modified to receive with CRC. Step 2 must be used to send commands to the reader/writer.
Figure 4 shows the Type A anticollision flowchart. The TRF7970A supports only 106 kbps for card emulation of Type A.