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NFC Forum Type 5 Tag Platform Operations with the TRF7970A

NFC Forum Type 5 Tag Platform Operations with the TRF7970A. NFC/RFID Training Module (2014) S2 MCU NFC/RFID Applications Team. Overview of NFC Forum Type 5 Tag Platform Operations.

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NFC Forum Type 5 Tag Platform Operations with the TRF7970A

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  1. NFC Forum Type 5 Tag Platform Operations with the TRF7970A NFC/RFID Training Module (2014) S2 MCU NFC/RFID Applications Team

  2. Overview of NFC Forum Type 5 Tag Platform Operations • TRF7970A being used with NFC Forum Type 5 Tag Platform operations is possible using Direct Mode 2 (default mode of the TRF7970A) • TRF7970A will be configured for ISO15693 operations by MCU • TRF7970A (+ MCU) will activate and select the Type 5 tag platform using ISO15693 standard command flow • After activation and selection, Reading of the data blocks will be executed. • 15693 can be NDEF formatted.

  3. ISO15693-3 • ISO15693 General Command Request Format: • The Request Flags are just as important as the command codes in ISO15693-3. The Request Flags are defined in Tables 3, 4 and 5 of the ISO15693-3 standard. Anyone who is using this standard will need to become familiar / friendly with these tables! Table 4 Table 3 Table 5

  4. ISO15693-3 • ISO15693 Command Set:

  5. ISO15693-3 • Formulating ISO15693 Command Examples with Request Flags detail: • Implementing the Inventory Command, which uses Tables 3 & 5 • Implementingthe Read Single Block Command, which uses Tables 3 & 4

  6. ISO15693-3 Anti-Collision • Explanation of an anti-collision sequence: • The following text and figure summarizes the main cases that can occur during a typical anti-collision sequence where the number of slots is 16. The different steps are: • The VCD sends an inventory request, in a frame, terminated by an EOF. The number of slots is 16. • VICC 1 transmits its response in slot 0. It is the only one to do so, therefore no collision occurs and its UID is received and registered by the VCD • The VCD sends an EOF, meaning to switch to the next slot. • In slot 1, two VICCs 2 and 3 transmits their response, this generates a collision. The VCD detects it and remembers that a collision was detected in slot 1. • The VCD sends an EOF, meaning to switch to the next slot. • In slot 2, no VICC transmits a response. Therefore the VCD does not detect a VICC SOF and decides to switch to the next slot by sending a EOF. • In slot 3, there is another collision caused by responses from VICC 4 and 5 • The VCD then decides to send an addressed request (for instance a Read Block) to VICC 1, which UID was already correctly received. • All VICCs detect a SOF and exit the anti-collision sequence. They process this request and since the request is addressed to VICC 1, only VICC1 transmit its response. • All VICCs are ready to receive another request. If it is an inventory command, the slot numbering sequence restarts from 0. NOTE:The decision to interrupt the anti-collision sequence is up to the VCD. It could have continued to send EOF’s till slot 15 and then send the request to VICC 1.

  7. Activating & Selecting a Type 5 tag • First we configure the TRF7970A as ISO15693 reader/writer by writing registers: • 0x09 0x01 (100% MOD depth, for ISO15693) • 0x00 0x21 (+5VDC ops, Full TX power out) • 0x01 0x02 (CRC expected in response) • Then we issue Inventory to activate the card: • 0x8F, 0x91, 0x3D, 0x00, 0x30, 0x26 (or 0x06), 0x01, 0x00. The Inventory below is sending out a 16 slot inventory with no mask. Send w/ CRC Mask Length Reset FIFO Write Continuous Inventory Command Flags Send 3 bytes

  8. EOTX IRQ • After the Inventory is transmitted, the EOTX IRQ is received, serviced, FIFO is cleared. • This first period after the EOTX IRQ is the 1st slot. If we are doing single slot inventory, then this will be our only slot. • If we are doing 16 slot Inventory (Anti-collision) we will need to send the TX next slot command after each slot has timed out. Reset FIFO EOTX IRQ and servicing

  9. 1 Slot (no response) • As you can see below, we only sent 1 slot and timed out. Inventory Command Single slot (No Response) If no response to inventory in 755us, time out. TRF79xx has the ability to generate a No-response IRQ based on the technology type. EOTX IRQ No-Response Interrupt

  10. 16 Slot (no response) Inventory Command EOTX IRQ 16 slots (No Responses) After each slot times out. Reading RSSI Values Clear FIFO Direct Commands: Block Receiver, Enable Receiver, TX next slot

  11. Inventory Response Read FIFO State (length) EORX IRQ DSFID Flags UID Reset FIFO

  12. Inventory Response • 0x00 on Error flags means no errors. • DSFID: Data Storage Format Identifier • UID: 8 bytes, received LSB first DSFID Error Flags UID Reset FIFO

  13. Optional 15693 Commands • Our current example code can also do “Read Single Block” and “Read Multiple blocks” • Lets take a look at these commands in the spec, and on the LSA.

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