Reading LM7002M analog RSSI (LimeSDR XTRX)

Projects LimeSDR
1

I need to read analog (RF) RSSI in order to adjust RF input level to XTRX.

The value of LMS7002 register 0x0605 does not change when RF input level changes.

I used limeGUI (limeSuiteNG) to set up XTRX and had waveform and PSD displayed. The antenna input was LNAW.

I performed RX calibration and full calibration. The value of LMS7002 register 0x0605 stays at constant 0x1D1D for all RF input level.

Thanks in advance for suggestions to have analog RSSI working.

2

I found bits 11-10 of the AFE register 0x0082 have to be set to 3 to have analog RSSI working:

“3 – RSSI 1 output will be connected to ADC 1 input.” (from LMS7002M_Programming_and_Calibration_Guide).

The “lms7002m_calibrate_analog_rssi_dc_offset” function in LimeSuiteNG returns “Failed to find Value”.
The lowest reading from register 0x0605 is always 159.