User's Manual

TRF7970A
www.ti.com SLOS743K –AUGUST 2011–REVISED APRIL 2014
6.14.3 Detailed Register Description
6.14.3.1 Main Configuration Registers
6.14.3.1.1 Chip Status Control Register (0x00)
Table 6-25. Chip Status Control Register (0x00)
Function: Control of Power mode, RF on/off, AGC, AM/PM, Direct Mode
Default: 0x01, preset at EN = L or POR = H
Bit Name Function Description
Standby mode keeps all supply regulators, 13.56-MHz SYS_CLK oscillator
1 = Standby Mode
running. (typical start-up time to full operation 100 µs)
B7 stby
0 = Active Mode Active Mode (default)
Provides user direct access to AFE (Direct Mode 0) or allows user to add their
1 = Direct Mode 0 or 1 own framing (Direct Mode 1). Bit 6 of ISO Control register must be set by user
B6 direct
before entering Direct Mode 0 or 1.
0 = Direct Mode 2 (default) Uses SPI or parallel communication with automatic framing and ISO decoders
1 = RF output active Transmitter on, receivers on
B5 rf_on
0 = RF output not active Transmitter off
TX_OUT (pin 5) = 8-Ω output impedance P = 100 mW (20 dBm) at 5 V,
1 = half output power
P = 33 mW (+15 dBm) at 3.3 V
B4 rf_pwr
TX_OUT (pin 5) = 4-Ω output impedance P = 200 mW (+23 dBm) at 5 V,
0 = full output power
P = 70 mW (+18 dBm) at 3.3 V
1 = selects Aux RX input RX_IN2 input is used
B3 pm_on
0 = selects Main RX input RX_IN1 input is used
1 = AGC on Enables AGC (AGC gain can be set in register 0x0A)
B2 agc_on
0 = AGC off AGC block is disabled
1 = Receiver activated for Forced enabling of receiver and TX oscillator. Used for external field
external field measurement measurement.
B1 rec_on
0 = Automatic Enable Allows enable of the receiver by Bit 5 of this register (0x00)
1 = 5 V operation
B0 vrs5_3 Selects the V
IN
voltage range
0 = 3 V operation
6.14.3.1.2 ISO Control Register (0x01)
Table 6-26. ISO Control Register (0x01)
Function: Controls the selection of ISO Standard protocol, Direct Mode and Receive CRC
Default: 0x02 (ISO15693 high bit rate, one subcarrier, 1 out of 4); it is preset at EN = L or POR = H
Bit Name Function Description
0 = RX CRC (CRC is present in the response)
B7 rx_crc_n CRC Receive selection
1 = no RX CRC (CRC is not present in the response)
(1)
0 = Direct Mode 0
B6 dir_mode Direct mode type selection
1 = Direct Mode 1
0 = RFID Mode
B5 rfid RFID / Reserved
1 = NFC or Card Emulation Mode
RFID: See Table 6-27 for B0:B4 settings based on ISO protocol desired by
application
B4 iso_4 RFID / NFC Target
NFC:
0 = target
1 = initiator
NFC:
B3 iso_3 RFID / NFC Mode
0 = passive mode
1 = active mode
(1) Only applicable to ISO-14443A and ISO-15693
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