OpenBSC April 2009

openbsc@lists.osmocom.org

13 participants
54 discussions

Re: BS-11 PLL clock source / calibration

by Dieter Spaar

Hello Christian, On Thu, 30 Apr 2009 03:13:33 +0200, "hotshot" <hotshot(a)koeln.ccc.de> wrote: > > Unfortunately I see the same behavior (even with restarting the > BS-11) as in E1-locked ('hfcmulti' and 'hfcmulti port=0x200) - a > network scan shows either your BS-11 or the other networks and only > sometimes you see all networks In the latest OpenBSC version there is support to show the "Set Value" and the "Work Value" of the PLL setting. The "Set Value" is the configuration value from the factory. The "Work Value" is not 100% clear yet but most certainly it is the value the PLL is actually using. In "Locked" mode the PLL follows the E1 clock and the "Work Value" can change quite a lot. Switching to "Standalone" mode seems to freeze the current "Work Value". The question now is if the PLL still used this "Work Value" in "Standalone" mode. If yes and the "Work Value" is off by a large amount the clock is not accurate (although its most certainly stable) and you still won't the test network and the other networks at once. If the "Work Value" of your BS-11 is off by a large amount from the "Set Value" you can try to switch to "Locked" mode and watch if the "Work Value" follows the E1 clock. If its close to the "Set Value", switch back to "Standalone" mode. I have not tested this and I don't know a better way yet (I don't think the "Work Value" can be set from the outside) but you can give it a try. Best regards, Dieter -- Dieter Spaar, Germany spaar(a)mirider.augusta.de

16 years, 5 months

Re: BS-11 PLL clock source / calibration

by Dieter Spaar

Hello Harald, On Fri, 17 Apr 2009 10:17:13 +0200, "Harald Welte" <laforge(a)gnumonks.org> wrote: > > Dieter, what I just found out is that the LI object has a user-configurable > setting, where we can force it to be stand alone or locked to the E1. > > We could add this setting to the bs11_config program so people can try > if their E1 clock or their [10 years uncalibrated] BS11 internal oscillator > is better. > > What do you think? I did a quick test with this setting and it seems to work fine with the BS-11 (so we should not believe the documentation ;-). Here is the LMT dump for the PLL Mode, it can be changed during normal operation: ; Locked Tx D0A5070000FC0102 Rx D1A5070000FC0102 ; Standalone Tx D0A5070000FC0103 Rx D1A5070000FC0103 A little bit strange is the behaviour of NM_ATT_BS11_CCLK_ACCURACY, if the PLL Mode is set to "Standalone", it changes to "high accuracy", however if you restart the BS-11, this attribute stays at "medium accuracy". Maybe NM_ATT_BS11_CCLK_ACCURACY has no meaning if the PLL Mode is set to "Standalone". Best regards, Dieter -- Dieter Spaar, Germany spaar(a)mirider.augusta.de

16 years, 5 months

Re: MBCCU0: No Load

by Dieter Spaar

Hallo Bjoern, > I tried it several times, > and left the BTS on over night. > The LMT cable wasn't always plugged in. > When I boot up the BTS it always says that the second TRX > has Load and the first not. You did turn the power off for a restart, just to be sure ? > If I try to bring up the BTS with your SW under Win. > I get the Abis Link Up but when I try the Load DB I get some > error messages on LMT. > Then the second TRX goes down to No Load. If the firmware for the first TRX is not loaded, the Abis communication will still work because the microcontroller which takes care about the commnunication is working. The error messages result from the not working TRX (I guess it would work if TRX1 instead of TRX0 is used, however I have not tried it yet). > And this is the condition until I reboot the BTS. > Maybe its a software issue? I don't think so because the communication processor loads the same firmware in both TRX. This is done in parallel. In your trace there is the same behavior I experience here, loading the firmware for TRX0 ad TRX1 starts, however loading TRX0 stops immediately. Of course I can only speak for my BS-11, but here it is most certainly a hardware issue (at one time I could even see an error message that the first power supply unit did not start). Best regards, Dieter -- Dieter Spaar, Germany spaar(a)mirider.augusta.de

16 years, 5 months

AW: [patch] support for recent Single E1 PCI ISDN cards tolinux-2.6.27.4

by Andreas.Eversberg

i must check with cologechip (vendor), if the subvendor id is correct, then i will check it into the GIT. -----Ursprüngliche Nachricht----- Von: openbsc-bounces(a)lists.gnumonks.org [mailto:openbsc-bounces@lists.gnumonks.org] Im Auftrag von Harald Welte Gesendet: Montag, 27. April 2009 10:12 An: Nico Cc: openbsc(a)lists.gnumonks.org Betreff: Re: [patch] support for recent Single E1 PCI ISDN cards tolinux-2.6.27.4 Hi Nico, On Sun, Apr 26, 2009 at 12:54:36AM +0200, Nico wrote: > Here's a patch I've been using to get a SingleE1 PCI ISDN card (recently > bought from Junghanns.NET) to work with the hfcmulti.ko driver. I'm not > sure the mapping between the PCI subdevice id and the driver data is > right, but at least the card can "talk" to the BS-11 now. Thanks for your patch. I think this should be forwarded to the mISDN folks for mainline inclusion. Andreas Eversberg (reading this list) is heavily involved with them, maybe he can take care of that. > I'm curious if any of you are also using such cards and how they get > them to work. I've so far only worked with HFC-E1 evaluation boards so far, sorry. -- - Harald Welte <laforge(a)gnumonks.org> http://laforge.gnumonks.org/ ============================================================================ "Privacy in residential applications is a desirable marketing option." (ETSI EN 300 175-7 Ch. A6)

16 years, 5 months

[patch] support for recent Single E1 PCI ISDN cards to linux-2.6.27.4

by Nico

Hi, Here's a patch I've been using to get a SingleE1 PCI ISDN card (recently bought from Junghanns.NET) to work with the hfcmulti.ko driver. I'm not sure the mapping between the PCI subdevice id and the driver data is right, but at least the card can "talk" to the BS-11 now. I'm curious if any of you are also using such cards and how they get them to work. Best regards, -- Nico

16 years, 5 months

Re: MBCCU0: No Load

by Dieter Spaar

Hello Bjoern, [ I sent it to the OpenBSC list too, because there are the Linux experts ] > Ok, Ill give it a try later on today. > Just one thing: > Ive now compiled OpenBSC on a fresh installed Debian lenny machine, > and LMT etc. works great but if I try to start bsc_hack I get the > following: > > gsmbase1:/home/tec/openbsc/src# ./bsc_hack > DB: Database initialized. > DB: Database prepared. > could not open socket Address family not supported by protocol > > It seems to be related to af_packet Kernel module, but I cant find the > mod. > > Do you have an idea? Don't ask me about Linux details, I am coming from Windows ;-) Maybe it is related to mISDN, I think there is also a special tunnel for capturing the traces in Wireshark. The rest (Telnet interface) should be standard socket operations. Maybe someone else can give a better explanation, the above is just my understanding. Best regards, Dieter -- Dieter Spaar, Germany spaar(a)mirider.augusta.de

16 years, 5 months

AW: first patch: mISDN handling

by Andreas.Eversberg

i just want to know, if my recent patch arrived on this list (my last mail), because my first mail formatting was detected as spam. i see no reaction to my last mail.

16 years, 5 months

German podcast about OpenBSC

by Harald Welte

JFYI, there now is a Chaosradio Express podcast about OpenBSC available at http://chaosradio.ccc.de/cre120.html Regards, -- - Harald Welte <laforge(a)gnumonks.org> http://laforge.gnumonks.org/ ============================================================================ "Privacy in residential applications is a desirable marketing option." (ETSI EN 300 175-7 Ch. A6)

16 years, 5 months

Re: BS-11 PLL clock source / calibration

by Dieter Spaar

Hello Harald, On Fri, 17 Apr 2009 10:17:13 +0200, "Harald Welte" <laforge(a)gnumonks.org> wrote: > > Dieter, what I just found out is that the LI object has a user-configurable > setting, where we can force it to be stand alone or locked to the E1. You mean the "PLL synchonisation mode" attribute which is set to "locked mode" ? I am not sure if we can change it for our version of the BS-11. As far as I understand the documentation, this is a setting which is only available with the CCU ("Combo Card Unit", the universal interface which also allows to use a standard ISDN line). The documentation mentions at one place that for the CCU variant they use an oven controlled oscillator which fulfilles the GSM clock stability requirements even without being snchronized to the E1 line. But we should of course try it. > We could add this setting to the bs11_config program so people can try > if their E1 clock or their [10 years uncalibrated] BS11 internal oscillator > is better. > > What do you think? Yes, why not try it. Probably the result is similar to disabling the master clock of the HFC-E1 card, this way the BS-11 clock determines the E1 clock (the HFC-E1 card synchronizes to the trasmitter E1 clock of the BS-11 and the BS-11 locks to the transmitter clock of the HFC-E1 which is determined by the BS-11). Surely the cleaner way is to adjust the clock setting in the BS-11 (if this settings works for our BS-11 variant). > I'm quite sure there must be an option to do this externally. The internal > oscillator must be calibrated every two years, and I'm sure they do this > without opening the case (in the field...) Its possible to calibrate the PLL without opening the case. The attribute is protected by some checksum, I have not looked at the details. And "officially" out LMT version should not even allow to see the calibration dialog ;-) The problem for me is how to measure the clock without opening the case. I can measure an unmodulated carrier very accurate if it is within the 10 MHz to 1 GHz range (the HP 8922 is accurate enough to do this). However I don't have the equippment to measure the modulated and pulsed signal of the BS-11. Maybe there is some hidden setting to send just the unmodulated carrier, but I have not yet found anything in this direction. Another problem is that changing the calibration requires a restart of the BS-11 (at least I only saw any effect when I restarted). Additionally when you query the calibration, you get the "PLL Set Value" and the "PLL Work Value", the "Set Value" seems to be used when starting up and the "Work Value" changes, most certainly locking to an external clock also influences it. I did not find anything in the documentation, actually those settings are not indended for the end user, just the factory. Best regards, Dieter -- Dieter Spaar, Germany spaar(a)mirider.augusta.de

16 years, 5 months

BS-11 clock accuracy

by Dieter Spaar

Hello, I think I finally found a way to measure the frequency of the BS-11 in a reliable way. My BS-11 is accurate to within 0.1 ppm if the oscillator is set to "Standalone Mode". If the oscillator is locked to the E1 clock of the HFC-E1 card and the HFC-E1 card is generating the clock, the frequency of the BS-11 drifts more than +/-1 ppm in about one minute. I did just a short test, but this results fits to the previous observations (remember, an old Nokia phone was not able to see the official networks and the test network at the same time if the frequency of the test network is off by more than 1 ppm). Of course I don't know how good the calibration of the other BS-11 units is, but setting the oscillator to "Standalone Mode" surely is better than using the HFC-E1 card for synchronisation (if the HFC-E1 card is not synchronized to the official ISDN network clock as Andreas suggested). Best regards, Dieter -- Dieter Spaar, Germany spaar(a)mirider.augusta.de

16 years, 5 months

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OpenBSC April 2009