LimeSuiteNG Support for C programs

System Development
1

I have a suite of C programs (such as LimeSDR BandViewer -

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) that run on a Raspberry Pi 4 using LimeSuite. I am trying to migrate these programs to use LimeSuiteNG, but cannot find a C-compatible header file. Many of the header files referenced by “limesuiteng/limesuiteng.hpp” are only compatible with C++.

Migrating these complex programs to C++ is not an option. Do I have stick with legacy LimeSuite or is there a migration path to LimeSuiteNG for existing C programs?

Or am I missing something simple?

Thanks

Dave, G8GKQ

2

LimeSuiteNG provides backwards compatibility to the lime/LimeSuite.h C header, so you should be able just relink your code to the liblimesuiteng library, and it should work without any code changes necessary.
https://limesuiteng.myriadrf.org/development/migration/lms/changes

3

Hi @ricardas Thanks for getting back to me, sorry for the delayed reply - I had to rebuild as I had given up and reverted to the legacy LimeSuite.

I now have it working, but there are a few issues:

  • I had to use #include “/home/pi/LimeSuiteNG/src/include/lime/LimeSuite.h” as LimeSuite.h is not installed to /usr/local/include/limesuiteng/.

  • The call LMS_GetChipTemperature(device, 0, &Temperature); failed with a LimeSDR Mini V1.2 with the error message terminate called after throwing an instance of 'std::logic_error' what(): LimeSDR-Mini v1 doesn't have a temperature sensor This call works and returns a sensible temperature in legacy LimeSuite.

  • The call LMS_GetDeviceInfo(device); returns a gateware version of v1 whereas legacy LimeSuite returns v1.30 with the same hardware.

  • Lastly, a comment for anyone else using c and migrating to LimeSuiteNG, the makefile libflags needs to be -llimesuiteng , all lower case, not CamelCase as was required by legacy LimeSuite.

I hope that you don’t think that I am being too critical at this early stage, but it would be good if you were able to document (or fix) some of these points.

I’ll add any more issues that I find to this topic.

Thanks again

Dave

1 Like
4

Not at all and thanks for the feedback, this is really helpful.

5

A few more (minor) observations:

  • During compile with gcc (Debian 12.2.0-14) 12.2.0 on a Raspberry Pi 4, I get this warning:
In file included from lime.c:13:
/home/pi/LimeSuiteNG/src/include/lime/LimeSuite.h:785:69: warning: ‘struct LMS7002MCSR’ declared inside parameter list will not be visible outside of this definition or declaration
  785 | API_EXPORT int CALL_CONV LMS_ReadParam(lms_device_t* device, struct LMS7002MCSR param, uint16_t* val);
      |                                                                     ^~~~~~~~~~~
/home/pi/LimeSuiteNG/src/include/lime/LimeSuite.h:796:70: warning: ‘struct LMS7002MCSR’ declared inside parameter list will not be visible outside of this definition or declaration
  796 | API_EXPORT int CALL_CONV LMS_WriteParam(lms_device_t* device, struct LMS7002MCSR param, uint16_t val);
      |                                                                      ^~~~~~~~~~~
  • The command n = LMS_GetDeviceList(list) gives a warning of:
ls: cannot access '/sys/class/litepcie': No such file or directory
  • LMS_Open(&device, list[0], NULL) also gives the same warinng:
ls: cannot access '/sys/class/litepcie': No such file or directory
  • LMS_GetDeviceInfo(device) returns 0x0000000000000000 for the device_info->boardSerialNumber

Nothing serious here - my application works!

Thanks

Dave

6

Today I have been trying to get transmit to work, but without any success. I recompiled the programs that I use with legacy LimeSuite and got them to the stage where they would run, but have ended up with no RF output and no error messages,

So, I tried with the example basicTX program compiled during LimeSuiteNG install. That does not appear to work with a LimeSDR Mini (V1) either:

pi@raspberrypi:~/LimeSuiteNG/build/bin/examples $ ./basicTX
Devices found :
0: LimeSDR Mini, media=USB 3.0, addr=0403:601f, serial=1D4C2CAE8C28A4

terminate called after throwing an instance of 'std::out_of_range'
  what():  vector::_M_range_check: __n (which is 1) >= this->size() (which is 1)
Aborted

Grateful for any pointers as to what might be causing this.

(LimeSuite NG commit 752ffea, Raspberry Pi OS Debian bookworm lite, 64 bit)

Dave, G8GKQ

7

My bad, the exception in the example was caused by bad device index. FIxed it.
Thanks for the feedback. I’ve added the legacy headers installation, and fixed the Mini board regressions.

8

Thanks @ricardas

I now have the basicTX program running and also see that the header location, temperature and gateware version fixes work.

Now to try to make it generate DVB-S2!

Dave

9

I’m finding a number of issues with the TX side of the legacy LimeSuite support. The first is Antenna selection. I have not yet succeeded in switching to the correct TX antenna path for a LimeSDR Mini at 437 MHz.

One issue is that LMS_GetAntennaList(device, is_tx, channel, list) returns the following:

i = 0, Antenna = NONE
i = 1, Antenna = Band1
i = 2, Antenna = Band2
i = 3, Antenna = Auto

Whereas legacy LimeSuite returns

i = 0, Antenna = NONE
i = 1, Antenna = BAND1
i = 2, Antenna = BAND2
i = 3, Antenna = Auto

So text matches against antenna bands fail.

However, even by setting the antenna manually to 0, 1, 2 or 3, I see no difference in the (very low) output power. I am sure that the antenna selection is not working.

A lesser problem is that in legacy LimeSuite, LMS_GetAntennaList(device, is_tx, channel, NULL) would return the number of available antenna options. In LimeSuiteNG it terminates the program.

I will reply separately on other issues.

Dave, G8GKQ

10

The next issue is that FIR filtering does not seem to work.

DVB-S2 signals which would usually have a square spectrum shape have a sinx/x spectrum shape as though no filtering is applied. The spectrum does generate a valid DVB-S2 decode, but is totally unsuitable for transmission.

Attempts to use oversampling and introduce a custom filter using
LMS_SetGFIR(device, LMS_CH_TX, 0, LMS_GFIR3, true)
result in no RF output at all. I have checked that the correct coefficients are being applied through
LMS_SetGFIRCoeff(device, LMS_CH_TX, 0, LMS_GFIR3, xcoeffs, 119)
by using
LMS_GetGFIRCoeff(device, LMS_CH_TX, 0, LMS_GFIR3, xcoeffsout)
to read them out.

The exact same code works with legacy LimeSuite on the same platform (Raspberry Pi 4 64-bit bookworm) perfectly.

Dave, G8GKQ

11

Hi Dave,

Thanks for reporting these. I’m sure @ricardas will take a look, but also where something clearly looks like a bug, feel free to raise an issue on the tracker: