AnsweredAssumed Answered

Custom gaintable fails - "failed to find suitable LPF TIA value in gain table"

Question asked by Baroch on Oct 9, 2017
Latest reply on Oct 19, 2017 by Vinod

My setup: AD FMCOMMS5 on XILINX 706.
linux kernel 4.6.0 21/11/2016
driver version - have run adi_update_boot and adi_update_tools around 20-sept-2017

We've created our own gain table -
<list>
<gaintable AD9361 type=FULL dest=3 start=1000000 end=4000000000>
1, 0x00, 0x40, 0x06
20, 0x00, 0x53, 0x06
</gaintable>
</list>

 

1. I couldn't find in the documentation an explanation about how should I calculate the number that starts each row in the gain table, so I assumed that it's the decimal sum of gains in db. Am I right?

 

no errors appear as we set up the gaintable and switch mode to manual gain.

However, when we call fir_filter_enable, we get the following error 2-4 times:

ad9361: spi32766.O: failed to find suitable LPF TIA value in gain table

 

 

we've added the row "1, 0x00, 0x40, 0x06" which has TIA index = 1 and LPF index = 0. but still the error is there.

 

2. I've looked at this forum post - https://ez.analog.com/thread/93330
the solution in this forum post sugests writing to the register " Tx quad full/LMT gain". Does this mean coding SPI write or can this be done using just the iio and/or linux driver's filesystem interface?

 

3. our setup requires only receiving - can we maybe go around the issue by disabling Tx? and so skip the entire tx quad check? got the idea from this post: https://ez.analog.com/thread/99597 - Does this mean coding SPI write or can this be done using just the iio and/or linux driver's filesystem interface?

 

4. looking into the driver's sourcecode, it looks like this error comes from the function ad9361_tx_quad_calib() (row 2703) by checking a binary value that is set on ad9361_load_gt() . There, in line 1226, it actually iterates over the array and looks specifically for a row with TIA index = 1 and LPF index = 0 so how come our gaintable failed this condition?

 

Thanks,
Baroch

 

 

BTW: our fir_filter_config is:
TX 3 GAIN -6 INT 4
RX 3 GAIN 6 DEC 3
RTX 1474560000 737280000 737280000 368640000 184320000 46080000
RRX 1474560000 737280000 737280000 368640000 184320000 46080000
BWTX 7500000
BWRX 7500000
0,0
0,0
0,0
0,0
0,0
0,0
0,0
0,0
0,0
0,0
0,0
0,0
0,0
0,0
0,0
0,0
0,0
0,0
0,0
0,0
0,0
0,0
0,0
0,0
0,0
0,0
0,0
0,0
0,0
0,0
0,0
0,0
0,0
0,0
0,0
0,0
0,0
0,0
0,0
0,0
0,0
0,0
0,19322
0,20269
0,21199
0,22110
0,22999
0,23863
0,24699
0,25506

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