ST25R200 datasheet(22/88 Pages) STMICROELECTRONICS

22 / 88 page

Figure 17. Transceiver operation with timeout

RF field

Data

Tx data

NRT

MRT

Receiver

I_txe

Interrupts

I_nre

MS71324

Figure 18. Transceiver operation with nrt_emd=0

RF field

Data

Tx data

Rx data

NRT

MRT

Receiver

I_txe

I_rxs

I_rxe

Interrupts

MS71325

Figure 19. Transceiver operation with nrt_emd=1

RF field

Data

Tx data

Rx data

NRT

MRT

Receiver

I_txe

I_rxs

I_rxe

Interrupts

I_nre

MS71326

5.10.1

ISO 14443A/NFC-A short frames

ISO14443A/NFC-A short frames (REQA/SENS_REQ and WUPA/ALL_REQ) are transmitted in the same manner

via the FIFO. The number of data to be sent shall be defined to zero bytes and seven bits. As the response to

these requests (ATQA/SENS_RES), does not contain CRC, the bit rx_crc shall be cleared.

5.10.2

Bit-oriented anticollision

In order to receive bit-oriented anticollision frames, the bit antcl has to be set.

For ISO14443A/NFC_A bit oriented anticollision, the bit rx_nbtx shall be set so that nbtx<2:0> define the position

of the first bit in the first byte in consecutive reception.

Bit-oriented anticollision can be performed for both ISO14443A/NFC-A and ISO15693/NFC-V. When bit antcl is

set:

•

Level coll_lvl is used to detect colliding bits

•

Detected collision is signaled via IRQ with the flag I_col

ST25R200

Application information

DS13658 - Rev 2

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