LR1121
User Manual Rev 1.1
UM.LR1121.W.APP Mar 2023
59 of 130
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Proprietary & Confidential
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7.2.15 SetRssiCalibration
Command SetRssiCalibration(...) sets the gain offset for the on-chip power estimation:
• TuneGx(...) (arguments 2 to 10): RSSI Gain Tune values. A tune is a 4-bit signed value, where 1lsb = 0.5dB.
• GainOffset: Global offset added to the Gain Tune values. The offset is a 12-bit signed value, where 1lsb = 0.5dB.
The power seen by the LR1121 analog front-end is affected by external components such as the matching network, or RF
switches. An incorrect RSSI results in a sensitivity degradation in (G)FSK mode and an incorrect gain selection in LoRa and
GFSK mode. An incorrect gain can result in a missed detection (packet loss) or decreased resistance to interference.
By default, the chip is calibrated for the 868-915MHz band on the LR1121 EVK.
Table 7-19: SetRssiCalibration Command
Byte 0 1 2 3 4 5 6
Data from Host 0x02 0x29
Tune
G5(7:4)
G4(3:0)
Tune
G7(7:4)
G6(3:0)
Tune
G9(7:4)
G8(3:0)
Tune
G11(7:4)
G10(3:0)
Tune
G13(7:4)
G12(3:0)
Data to Host Stat1 Stat2
IrqStatus
(31:24)
IrqStatus
(23:16)
IrqStatus
(15:8)
IrqStatus
(7:0)
0
Byte 7 8 9 10 11 12
Data from Host
Tune
G13hp2(7:4)
G13hp1(3:0)
Tune
G13hp4(7:4)
G13hp3(3:0)
Tune
G13hp6(7:4)
G13hp5(3:0)
Tune
G13hp7(3:0)
Gainoffset
(15:8)
Gainoffset
(7:0)
Data to Host 0 0
Table 7-20: Gain Tune Values
Tune 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
value (dBm) 0 0.5 1 1.5 2 2.5 3 3.5 -4 -3.5 -3 -2.5 -2 -1.5 -1 -0.5
Table 7-21: Recommended Values for Reference EVK
Frequency
Gain Offset
G4 Tune
G5 Tune
G6 Tune
G7 Tune
G8 Tune
G9 Tune
G10 Tune
G11 Tune
G12 Tune
G13 Tune
G13hp1 Tune
G13hp2 Tune
G13hp3 Tune
G13hp4 Tune
G13hp5 Tune
G13hp6 Tune
G13hp7 Tune
below 600MHz 0 12 12 14 0 1 3 4 4 3 6 6 6 6 6 6 6 6
from 600MHz
to 2GHz
0 2 2 2 3 3 4 5 4 4 6 5 5 6 6 6 7 6
above 2GHz 2030 6 7 6 4 3 4 14 12 14 12 12 12 12 8 8 9 9
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