Hi everyone,
I was trying to get TDD control to work on the LimeFEA board. After some attempts wanted to double-check with others whether my findings about it not yet being fully implemented correct? (in the code it seems that the TDD control in the limeGUI only assigns ch.rx.centerFrequency and does not set any GPIO, and the GPIO is not yet implemented for XTRX boards).
P.S. Is the GPIO3N supposed to be a negation of what the GPIO3 is set via API (not necessarily now, but in the future. I am a bit confused about GPIO3N and GPIO3P)?
TDD should definitely work with XTRX as we are using these in turnkey 5G NR TDD systems. Though not sure about setup and pins, but @VytautasB and @ricardas could no doubt advise.
Thanks for the reply and the information. Maybe it is using slightly different APIs or something. I’d dump some findings from my side, maybe I am just looking in the wrong direction 
I am using LimeSuiteNG at the revision 7495584276b
LimeFEA mPCIe Full
The XTRX information is
0: LimeSDR XTRX, media=PCIe, addr=/dev/limepcie0, serial=ffffffffffffffff
Expansion name : UNSUPPORTED
Firmware version : 4
Gateware version : 1
Gateware revision : 22
Gateware target board : LimeSDR XTRX
Hardware version : 2
Protocol version : 1
Serial number : 18446744073709551615
SPI slave devices :
FPGA
LMS7002M
Memory devices :
EEPROM
FPGA/FLASH
FPGA/gold-image
FPGA/user-image
GPS Lock:
GPS - Undefined
Glonass - Undefined
Galileo - Undefined
Beidou - Undefined
From my understanding the TDD is based on a GPIO pin. So as part of the tests I’ve tried gpio_example, and it gives the following error:
Read current GPIO state:
GPIORead not implemented
And in the limeGUI code I’ve only found this line, which onlty modifies the rx frequency, but does not seem to do any GPIO related operations: LimeSuiteNG/GUI/SDRConfiguration_view.cpp at 7495584276b8b5ab0a12885ab38def190eb5bbcd · myriadrf/LimeSuiteNG · GitHub
Maybe I’ve misunderstood the purpose of the TDD option in the GUI though.
