0
1
2
3
4
5
6
7
0
25
50
75
100
125
150
175
200
225
250
275
300
325
RF Input Voltage Level at Pin RF_IN1 (mV )
PP
RSSI Levels and Oscillator Status Register V
alue (0x0F)
0
1
2
3
4
5
6
7
0
0.25
0.5
0.75
1
1.25
1.5
1.75
2
2.25
2.5
2.75
3
3.25
3.5
3.75
4
4.25
Input RF Carrier Level (V )
PP
RSSI Levels and Oscillator Status Register V
alue (0x0F)
20
SLOS758G – DECEMBER 2011 – REVISED MARCH 2020
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Detailed Description
Copyright © 2011–2020, Texas Instruments Incorporated
Figure 6-2. Digital Internal RSSI (Main and Auxiliary) Value vs RF Input Level
This RSSI measurement is done during the communication to the Tag; this means the TX must be on.
Bit 1 in the Chip Status Control register (0x00) defines if internal RSSI or the external RSSI value is stored
in the RSSI Levels and Oscillator Status register 0x0F. Direct command 0x18 is used to trigger an internal
RSSI measurement.
6.7.1.2
External RSSI
The external RSSI is mainly used for test and diagnostic to sense the amplitude of any 13.56-MHz signal
at the receiver's RX_IN1 input. The external RSSI measurement is typically done in active mode when the
receiver is on but transmitter output is off. The level of the RF signal received at the antenna is measured
and stored in the RSSI Levels and Oscillator Status register (0x0F).
shows the relationship between the voltage at the RX_IN1 input and the 3-bit code.
Figure 6-3. Digital External RSSI Value vs RF Input Level
