Register Description - Texas Instruments TRF7970A Manual

TRF7970A
SLOS743L – AUGUST 2011 – REVISED MARCH 2017
If the command is executed immediately after power-up and before any communication with
a tag is performed, the command must be preceded by an Enable RX command. The Check
RF commands require full operation, so the receiver must be activated by Enable RX or by a
normal Tag communication for the Check RF command to work properly.
RF_IN1 [mV
PP
Decimal Code
Binary Code

6.15 Register Description

6.15.1 Register Preset
After power up and the EN pin low-to-high transition, the reader is in the default mode. The default
configuration is ISO/IEC 15693, single subcarrier, high data rate, 1-out-of-4 operation. The low-level option
registers (0x02 to 0x0B) are automatically set to adapt the circuitry optimally to the appropriate protocol
parameters. When entering another protocol (by writing to the ISO Control register 0x01), the low-level
option registers (0x02 to 0x0B) are automatically configured to the new protocol parameters. After
selecting the protocol, it is possible to change some low-level register contents if needed. However,
changing to another protocol and then back, reloads the default settings, and so then the custom settings
must be reloaded.
The Clo0 and Clo1 register (0x09) bits, which define the microcontroller frequency available on the
SYS_CLK pin, are the only 2 bits in the configuration registers that are not cleared during protocol
selection.
56 Detailed Description
Table 6-23. Test External RF Peak Level to RSSI Codes
] 40 60
1 2
001 010
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