Texas Instruments TRF7960 Manual page 30

TRF7960
TRF7961
SLOU186F – AUGUST 2006 – REVISED AUGUST 2010
Sets the gains and filters directly
Register default is set to 0x40 at POR = H or EN = L, and at each write to the ISO control register.
Bit Bit Name Function
B7 C212 Bandpass 110 kHz to 570 kHz
B6 C424 Bandpass 200 kHz to 900 kHz
B5 M848 Bandpass 450 kHz to 1.5 MHz
B4 hbt Bandpass 100 kHz to 1.5 MHz
Gain reduced for 7 dB
B3 gd1 01 gain reduction for 5 dB
10 gain reduction for 10 dB
B2 gd2
11 gain reduction for 15 dB
B1 agcr AGC activation level change
B0 no-lim AGC action is not limited in time
Control the three voltage regulators
Register default is set to 0x87 at POR = H or EN = L
Bit Bit Name Function
B7 auto_reg 0 = setting regulator by option bits
(vrs3_5 and vrs2, vrs1 and vrs0)
1 = automatic setting
B6 en_ext_pa Support for external power
amplifier
B5 io_low 1 = enable low peripheral
communication voltage
B4 Unused
B3 Unused
B2 vrs2 Voltage set MSB
B1 vrs1
B0 vrs0 Voltage set LSB
30 System Description
Table 5-20. RX Special Setting Register (Address 0Ah)
Comments
Appropriate for 212-kHz sub-carrier system
Appropriate for 424-kHz sub-carrier used in ISO15693 and Tag-It
Appropriate for Manchester-coded 848-kHz sub-carrier used in ISO14443A
Appropriate for highest bit rate (848 kbps) used in high-bit-rate ISO14443
Sets the RX gain reduction
AGC activation level changed from 5 times the digitizing level to 3 times the
digitizing level.
AGC action can be done any time during receive process. It is not limited to the
start of receive.
Table 5-21. Regulator and I/O Control (0Bh)
Comments
Auto system sets VDD_RF to VIN – 250 mV and VDD_A and VDD_X to VIN –
250 mV, but not higher than 3.4 V.
Receiver inputs accept externally demodulated sub-carrier, OOK pin becomes
modulation output for external amplifier.
When HIGH, it decreases output resistance of logic outputs. Should be set
HIGH when VDD_I/O voltage is below 2.7 V.
Default is LOW.
Default is LOW.
vrs3_5 = L: VDD_RF, VDD_A, VDD_X range 2.7 V to 3.4 V
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