LimeSDR-USB LED1 is Red

Good evening,

The LED1 of my LimeSDR-USB has suddenly turned red and it stays like this all the time. Before it was green like it was supposed. According to the information on the website this means that at least one PLL is not locked.

How can I fix this issue and set the LED green again. If there is no fix, how will this affect my performance? What could possibly be the reason for this to happen?

Thanks in advance.

@andrewback, @Zack? someone, please? This doesn’t seem an answer that hard to give. Any thoughts?

@OCB - Joao,

Having the LED turn red only means that the LimeSDR does not have good communications to the platform it’s plugged to. What I’d suggest doing is resetting the Lime by pulling it from the USB connection (and I would hope that’s a USB 3.0 port) and then plugging it back in and then running LimeSuite, connect to it, and then run some diagnostics to see if it’s communicating to LimeSuite (like the Device Info check). If the Lime is communicating (shows connected in the lower left window and shows some status) and if the firmware and gateware versions look correct, then you’re probably fine. If you cannot get your Lime to communicate then that’s another issue - check the power to the Lime and make sure it’s +5VDC at the minimum - some USB ports on a PC can get damaged or fail and that will create the situation you’re seeing too.

Try that and then report back your findings -

73 de Marty, KN0CK

Thanks for the reply.

The Lime is working, the only thing that I see different is that somehow the RX is able to acquire the transmitting signal of the TX of the same channel, even tho they are not connected in any sort (?). I can even receive an LMS_SetTestSignal from TX in the RX even when they are not connected and this didn’t happen before.

I’ve checked every USB port in my laptop and the LED is still red. I haven’t checked in other computers, but will do in a moment.

What sort of specific tests / command prompts do you recommend me to run?

Thanks in advance

@OCB - Joao,

Since I’m not familiar with your setup (Windows or Linux), I do see that you are able to do some code development since you’re using vernacular that the coders typically mention (LMS_SetTestSignal). So I’m also assuming that when you started to get your code environment for LimeSDR development together you did install the LimeSDR drivers, right? In Windows (if it’s Windows 10) once you plug in your LimeSDR the appropriate drivers are installed ( drivers). If not, you have to do that first to have the Lime operate correctly from USB 3.0 (another assumption - you can run a LimeSDR on USB 2.0, but not effectively - it’s better to run it off USB 3.0). If you’re running Linux, you have to install the LimeSuite application and the drivers will be part of the installation, as will the LimeSuite application that will help you test the LimeSDR you have.

Provided you have the drivers installed, you have to have LimeSuite installed to check your LimeSDR-USB. Generally, most LimeSDR users install the Pothosware installation for Windows and that installs not only the drivers, but it also installs LimeSuite and some other applications to run the LimeSDR on. You can find the Windows Pothosware installation here ---->

…and look for the latest version of the Pothosware install for, usually the first one on top of the list, and then kick off an install of Pothosware. Once it’s done, you can double-click on the LimeSuite application and then look for the OPTIONS tab on the Window and then click on CONNECTION SETTINGS and then click on the CONNECT button. If your LimeSDR is plugged in, you can see the result if the LimeSDR connects or not. If it does, then that’s a good thing - it tells you that everything is normal and the LED will not be blinking green. If it’s still blinking red even when you do this then chances are there’s another issue and we’ll have to sort that out on the next reply.

Try all that and let’s see where this leads -

73 de Marty, KN0CK


I have been developing software with my LimeSDR for over a year now. It just happens that the LED suddenly turned RED. Everything regarding software/drivers/etc is up to date and working. My LimeSDR applications still work as well, but the LED is RED and I want to know why could that be.

Hi @OCB,

Could you test your board with Quick Test software and post log file here, please.

Hi @Zack.

I’m not exactly sure on how to perform such test. My OS is Ubuntu. Are you referring to the LimeSuiteGUI test? If so, how can I obtain the log file?

If you are not, and instead you are referring to some script that I should run, I’m afraid I’m not exactly finding the instructions/code for Ubuntu from the link you have provided.

Thank you so much for your time.