UmTRX September 2012

umtrx@lists.osmocom.org

8 participants
12 discussions

Building FPGA and ZPU for UmTRX
by Alexander Chemeris 26 Sep '12

26 Sep '12

All, I've put together a short step-by-step on how to build FPGA image for UmTRX and how to flash it over Ethernet or a JTAG cable. Feel free to amend/comment on it: http://code.google.com/p/umtrx/wiki/BuildingUHD -- Regards, Alexander Chemeris. CEO, Fairwaves LLC / ООО УмРадио http://fairwaves.ru

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UHD support for tuning on UmTRX
by Alexander Chemeris 26 Sep '12

26 Sep '12

Hi all, I've just pushed changes to the 'fairwaves/umtrx' branch which allow UHD to actually control UmTRX tuning. This means that now we don't need to calculate Rx/Tx frequencies by hands to run OpenBTS - it will tune automatically. I've updated the wiki to reflect those changes as well. Changes are based on the Sergey Kostanbaev's work to move all our LMS6002 control from umtrx_lms.py script to the UHD. The next most important things to get working there are: * gains control aka VGA1/VGA2 in LMS * antenna control aka PA/LNA selection in LMS * bandwidth filtering control aka LPF filters in LMS * automatic calibration utilities -- Regards, Alexander Chemeris. CEO, Fairwaves LLC / ООО УмРадио http://fairwaves.ru

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VCOREG in LMS6002D
by Alexander Chemeris 25 Sep '12

25 Sep '12

Hi guys, Could anyone tell me, the software guy, what may be the purpose of VCOREG block in LMS6002D (Figure 3.4 at the Programming Guide)? In our current code it's always powered down and not used, and I just wonder whether it could be used for frequency hopping and what are other potential uses. If I understand correctly, it's a kind of fine tuning for the PLL output frequency. -- Regards, Alexander Chemeris. CEO, Fairwaves LLC / ООО УмРадио http://fairwaves.ru

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on board GPSDO?
by Jerry Giant 22 Sep '12

22 Sep '12

Hi, Very nice to see the progress UmRTX. I checked out the git found the GPS 1pps signal was terminated to FPGA, and wonder how the discipline algorithm was implemented. Someone would give me a hint or introductory? thanks in advance. Regards. Jerry

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Full dual-channel support on the host side
by Alexander Chemeris 22 Sep '12

22 Sep '12

Hi Thomas, I recall you had some patch to add a second Tx channel to the host UHD. Could you push it to git or send as a patch here? We're testing dual-channel FPGA firmware now and it would be of good help. -- Regards, Alexander Chemeris. CEO, Fairwaves LLC / ООО УмРадио http://fairwaves.ru

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Host integration ToDo
by Alexander Chemeris 21 Sep '12

21 Sep '12

Hi all, I've started putting together a ToDo list for UmTRX features which are missing support on the host side or the FPGA side. I invite everyone to add more tickets, fill details in existing tickets and discuss implementation strategies in comments. You could use this filter in our issues tracker to select at the tasks open at the moment: http://code.google.com/p/umtrx/issues/list?can=2&q=label%3AComponent-Host -- Regards, Alexander Chemeris. CEO, Fairwaves LLC / ООО УмРадио http://fairwaves.ru

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EEPROM size
by Alexander Chemeris 21 Sep '12

21 Sep '12

Andrey Sviyazov, How much space do we have in the EEPROM right now? I'm thinking which calibration data we could store there and which we should store on a host. -- Regards, Alexander Chemeris. CEO, Fairwaves LLC / ООО УмРадио http://fairwaves.ru

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UmTRXv2 are back from a fab
by Alexander Chemeris 20 Sep '12

20 Sep '12

Hi all, Today we've received first units of UmTRXv2 from a fab. The unit is lovely to look at - find the picture attached. I hope it will show no less great performance when we turn it on. In addition to fixed bugs this version has following major changes. I may have forgotten something, but these are the most important changes: * better form factor (10x16cm Eurocard) * doesn't have RF switches on board (the're moved to a frontend for higher flexibility) * newer GPS module (EB-570) * U.FL connectors by default (to simplify automated mounting) * optional connector for external front panel (for waterproof casing) * tantalum capacitors instead everywhere (for longer life) * wider input power voltage range (8-28VDC) We consider this version as pre-production. I.e. it will go into production if there are no serious bugs. Now our task is to bring up the board and check for all possible bugs before we go forward. PS White squares on the picture is not because we obscure the photo - it's white thermal pads which the fab placed atop of chips instead of placing them at the bottom of PCB. -- Regards, Alexander Chemeris. CEO, Fairwaves LLC / ООО УмРадио http://fairwaves.ru

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Re: UmTRXv2 - Stacking capability for the UMTRXv2 RF frontends.
by Alexander Chemeris 19 Sep '12

19 Sep '12

Hi Daud, I've copied the mailing list, as I believe the question belongs there. On Wed, Sep 19, 2012 at 1:20 AM, Daud Suleiman <msdaudi(a)gmail.com> wrote: > I am very excited and glad and happy for the UmTRX project. I would like to > know if you have plans for stacking capability for the RF frontend. I am > assuming that there is only 2TXs. Int he event that a client needs more TXs, > say 12TXs, have you any plans to stack as many RF frontends and or UmTRXs? Yes, we have an option to stack UmTRX'es, but it is only to share clock source and/or GPS source, i.e. you still have to connect each UmTRX to the Ethernet. As long as connecting to an Ethernet switch works fine, so we don't see this as an issue. Later we may consider implementing true stacking when stacked units share Ethernet port, like with USRPs. This might be a useful endeavor, but we don't want to dive into this until we have everything else settled. -- Regards, Alexander Chemeris. CEO, Fairwaves LLC / ООО УмРадио http://fairwaves.ru

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Hackathon results: working Rx
by Alexander Chemeris 16 Sep '12

16 Sep '12

Hi all, Some good news for today. We've had a small fairwaves hackathon here in Moscow and we've done a good progress in UmTRX development. I'm quite exhausted, thus in short: 1. A software issue has been fixed in PLL tuning code. It works reliably now. Previously it didn't correctly handle edge cases when the best VCOCAP value was at the end of a range. 2. A software issue has been fixed in automatic LMS calibration code. Turns out a process described in the datasheet is not complete - you have read FAQ, question 4.7 for an amendment. 3. Now we correctly select Rx input. You have to change _two_ registers to do that - 0x75 and 0x25. This wasn't obvious from the brief reading of the manual. 4. A hardware bug was fixed - RF diversity switch required a bias to work correctly. Luckily we decided to move the switch from the main board to a frontend in the rev2 of UmTRX. So we don't have to re-make the UmTRX schematics. Huge thanks to Andrey Sviyazov ("RF guy"), Andrew Karpenkov ("FPGA guy") and Srdjan Milenkovic ("remote LimeMicro guy") for going through all the issues. Fixes for the code will be pushed to github in the next few days after I clean it up. PS Another good news is that we should have first UmTRXv2 units on hands in the next few days, when we get them from customs. Can't wait to put my hands on them. -- Regards, Alexander Chemeris. CEO, Fairwaves LLC / ООО УмРадио http://fairwaves.ru

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UmTRX September 2012