Texas Instruments TRF7970A Instruction Manual page 24

TRF7970A
SLOS743K – AUGUST 2011 – REVISED APRIL 2014
The main register controlling the digital part of the receiver is the ISO Control register (address 0x01). By
writing to this register, the user selects the protocol to be used. At the same time (with each new write in
this register) the default preset in all related registers is done, so no further adjustments in other registers
are needed for proper operation.
Bit Signal Name
B7 rx_crc_n Receiving without CRC
B6 dir_mode Direct mode type
B5 rfid RFID mode
B4 iso_4 RFID protocol, NFC target
B3 iso_3 RFID protocol, NFC mode
B2 iso_2 RFID protocol, Card Emulation
B1 iso_1 RFID protocol, NFC bit rate
B0 iso_0 RFID protocol, NFC bit rate
Table 6-7. Coding of the ISO Control Register For RFID Mode (B5 = 0)
Iso_4 Iso_3 Iso_2
0 0 0
0 0 0
0 0 0
0 0 0
0 0 1
0 0 1
0 0 1
0 0 1
0 1 0
0 1 0
24 Detailed Description
Table 6-6 shows the coding of the ISO Control register (0x01).
Table 6-6. Coding of the ISO Control Register
Function
1 = No RX CRC
0 = RX CRC
0 = output is subcarrier data
1 = output is bit stream and clock from decoder selected by ISO bits
0 = RFID reader mode
1 = NFC or Card Emulator mode
RFID: Mode selection
NFC:
0 = NFC target
1 = NFC initiator
RFID: Mode selection (see
NFC:
0 = passive mode
1 = active mode
RFID: Mode selection
NFC:
0 = NFC normal modes
1 = Card Emulation mode
RFID: Mode selection
NFC: Bit rate selection or Card Emulation selection (see
RFID: Mode selection
NFC: Bit rate selection or Card Emulation selection (see
Iso_1 Iso_0
0 0 ISO15693 low bit rate, one subcarrier, 1 out of 4
0 1 ISO15693 low bit rate, one subcarrier, 1 out of 256
1 0 ISO15693 high bit rate, one subcarrier, 1 out of 4
1 1 ISO15693 high bit rate, one subcarrier, 1 out of 256
0 0 ISO15693 low bit rate, double subcarrier, 1 out of 4
0 1 ISO15693 low bit rate, double subcarrier, 1 out of 256
1 0 ISO15693 high bit rate, double subcarrier, 1 out of 4
1 1 ISO15693 high bit rate, double subcarrier, 1 out of 256
0 0 ISO14443A, bit rate 106 kbps
0 1 ISO14443 A high bit rate 212 kbps
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Comments
Table 6-7)
Protocol
Copyright © 2011–2014, Texas Instruments Incorporated
TRF7970A
www.ti.com
Table 6-8)
Table 6-8)
Remarks
Default for RFID IC
RX bit rate when TX rate
different from RX rate (see
register 0x03)