discuss-gnuradio
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Discuss-gnuradio] Unable to tune Tx or Rx with XCVR2450 on USRP2


From: Matt Ettus
Subject: Re: [Discuss-gnuradio] Unable to tune Tx or Rx with XCVR2450 on USRP2
Date: Wed, 03 Feb 2010 21:26:40 -0800
User-agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.7) Gecko/20100120 Fedora/3.0.1-1.fc12 Thunderbird/3.0.1


Manav,

Sorry for not being active in this thread. Things have been very busy here. In any case, it sounds like you are seeing something very different from Ian. You are having one of 2 problems --

- You received bad SD cards. If you power up your USRP2 with the SD card in it, and you don't see 2 LEDs light up on the front panel, then this is what you are seeing, and it has nothing to do with the XCVR2450. Go to this page and follow the directions there:

        http://www.ettus.com/flash

- If the card is not bad, then you have a flash version which does not match your GNU Radio install. Newer flash cards come with new versions of the firmware and FPGA, but these will only work with updated GNU Radio code. If this is the case, you either need to update GNU Radio, or put an old version of the FPGA and firmware on your card. I recommend the first option.

Matt


On 02/02/2010 05:08 PM, Manav Seth wrote:
Ya, what I mean is that for you too the problem may be the SD card only.
Actually we had got around 20 USRP's/daughterboards from Ettus and none
of them were working with the SD cards they supplied with them (20 in
all). When I tried with an older SD card, it worked.

On Tue, Feb 2, 2010 at 5:43 PM, Ian Holland <address@hidden
<mailto:address@hidden>> wrote:

    Hi Manav

    I tried both of my daughterboards with the same SD card in the
    USRP2, so perhaps we were actually facing different problems, or at
    least I am facing an additional problem with one of my cards.

    Your problem may be resolved once you try Josh’s earlier suggestion
    of reflashing the latest FPGA and firmware images, but of course you
    will need an SD card reader to do this. You should be able to find
    them at any electronics/photography/home entertainment store, and
    they are quite cheap.

    Ian.

    ------------------------------------------------------------------------

    *From:* Manav Seth [mailto:address@hidden
    <mailto:address@hidden>]
    *Sent:* Wednesday, 3 February 2010 10:54 AM
    *To:* Ian Holland
    *Cc:* address@hidden <mailto:address@hidden>;
    address@hidden <mailto:address@hidden>

    *Subject:* Re: [Discuss-gnuradio] Unable to tune Tx or Rx with
    XCVR2450 on USRP2

    Hi,


    The problem I guess is with the SD cards only. Even I was facing the
    same problem. But today I tried with an old SD card and it worked.
    I am not able to catch hold of a card reader and the one in my
    laptop is not working.

    manav

    On Tue, Feb 2, 2010 at 5:14 PM, Ian Holland
    <address@hidden <mailto:address@hidden>>
    wrote:

    Hi Josh

    Thanks for the advice. I tried the full range of low and high band
    frequencies, in increments of 10 MHz with 2 different XCVR2450 boards.
    This was done at least 4 times after power cycling for each card. I
    noticed the following:

    - For one of the XCVR cards, it repeatedly failed for all frequencies.
    - For the other card, it intermittently failed for frequencies at the
    lower and upper end of the low band, and at the higher end of the high
    band. I tried several values of N_DIV_MIN_Q16, and expect with a really
    large value (131 << 22), which seemed to fail for almost all
    frequencies, and also seemed to cause the USRP2 to "freeze up" a few
    times, I noticed negligible difference in the behaviour of this
    daughtercard.
    - For both XCVR2450s I noticed that sometimes after power cycling the
    USRP2 either froze when I tried to run my test, or it was unable to be
    found by my host PC in some cases.
    - I tried (131 << 16) (i.e. original) value for N_DIV_MIN_Q16 and also
    (131 << 19) on the card that failed for all frequencies, and that made
    no difference.

    I am not hugely concerned about the band-edge instability for the
    working card (although of course it would be nice to get to the bottom
    of that issue), but do you have any idea what could be wrong with the
    2nd card, that fails for all frequencies?

    Best Regards

    Ian.



    >Is it failing to lock at all different frequencies? and in the high
    band
    >and low band ranges? Do you have more than one XCVR board with this
    >problem?

    >It could be possible that for this board, and the frequencies you have
    >chosen, the N divider value teeters on the border or locking/not
    >locking. You may want to modify the usrp2 firmware code and build
    custom
    >image. The file to modify is
    >http://gnuradio.org/redmine/repositories/entry/gnuradio/usrp2/firmware/
    lib/
    
<http://gnuradio.org/redmine/repositories/entry/gnuradio/usrp2/firmware/%0Alib/>>db_xcvr2450.c

    >Add some printfs to the xcvr2450_set_freq function and try to raise the

    >value of N_DIV_MIN_Q16 and see if you can get it to lock.

    >I hope that helps,
    >-Josh

    On 02/01/2010 06:08 PM, Ian Holland wrote:
    >  Thanks Josh
    >
    >  I can now confirm that it is definitely failing to lock. I have
    noticed
    >  on some rare occasions that it actually does lock. However, as soon as
    >  the USRP2 is power-cycled it goes back to the default behaviour of
    being
    >  unable to lock.
    >
    >  What can be done to make sure that it will lock? Is this likely to be
    a
    >  hardware issue specific to our daughtercards, or is there something
    else
    >  we can do in software to get around it?
    >
    >  Thanks
    >
    >  Ian.
    >
    > > It could be failing to lock. You may want to watch the debug port on
    >  the
    > > usrp2. If the lock detect is failing, it will print out on the serial
    > > console. attach a 3.3v level serial port
    >
    >  On 01/28/2010 10:09 PM, Ian Holland wrote:
    > > Hi Josh
    > >
    > >> The xcvr has a high band and a low band, which means there is a gap
    >  in
    > >> the tunable frequency range for the xcvr. Therefore, the
    > >> "auto-calculated mid-point frequency" is an invalid frequency for
    the
    > >> xcvr. Pick a frequency in the high band or low band range:
    > >
    > >> #define LB_FREQ_MIN U2_DOUBLE_TO_FXPT_FREQ(2.3e9)
    > >> #define LB_FREQ_MAX U2_DOUBLE_TO_FXPT_FREQ(2.6e9)
    > >> #define HB_FREQ_MIN U2_DOUBLE_TO_FXPT_FREQ(4.8e9)
    > >> #define HB_FREQ_MAX U2_DOUBLE_TO_FXPT_FREQ(6.1e9)
    > >
    > > Thanks - I will keep that in mind when using usrp_siggen.py in
    future.
    > >
    > > However, I have tried 2.4G with the source code from my original post
    > > (relevant code snippet for Tx tuning just below this paragraph, for
    > > which successTx is 0 and all frequency properties in TxTuneResult are
    > > 0), and also with usrp2_fft.py -f 2.4G, after burning the latest
    >  images.
    > > I still face the same problem that neither the Tx nor the Rx will
    >  tune.
    > >
    > > /* try tuning Tx to a test frequency */
    > > double Fc = 2400000000.0;
    > > usrp2::tune_result TxTuneResult;
    > > bool successTx = device->set_tx_center_freq(Fc,&TxTuneResult);


    _______________________________________________
    Discuss-gnuradio mailing list
    address@hidden <mailto:address@hidden>
    http://lists.gnu.org/mailman/listinfo/discuss-gnuradio




_______________________________________________
Discuss-gnuradio mailing list
address@hidden
http://lists.gnu.org/mailman/listinfo/discuss-gnuradio





reply via email to

[Prev in Thread] Current Thread [Next in Thread]