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Re: [Discuss-gnuradio] USRP2 and external clock (from GPS receiver)
From: |
Douglas Geiger |
Subject: |
Re: [Discuss-gnuradio] USRP2 and external clock (from GPS receiver) |
Date: |
Fri, 20 Feb 2009 11:37:44 -0600 |
User-agent: |
Thunderbird 2.0.0.19 (Windows/20081209) |
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Matt Ettus wrote:
> Douglas Geiger wrote:
>> I'm at svn revision 10441 - with both the firmware and fpga code built
>> from that (using Xilinx ISE 10.1 to make the fpga). I've just modified
>> the txrx.c code - adding:
>> clocks_enable_test_clk(true, 2);
>> clocks_mimo_config(MC_WE_LOCK_TO_SMA);
>> just before the while(1) loop
>>
>> My rx_mimo.cc code also calls ->config_mimo(MC_WE_LOCK_TO_SMA), but
>> right now I've stepped back to just getting one USRP2 synchronized to my
>> external source - which in this case is a function generator with a
>> 10MHz sine with 2V P-P.
>>
>> Is it possible some of the hardware on my USRP2's isn't working?
>
> Unlikely, since it was tested before shipping.
>
> I will send you code to run in a separate email.
>
> Matt
Ok - now that I've discovered I had some bad cabling - specifically a
bad T-splitter: the side going to my O-scope worked, the side going to
my USRP2's did *not* - which I suppose can be chalked up to user error.
I am now able to synchronize the clocks - both with the firmware/fpga
code you sent, and the version I had built locally.
However - once I start running my code on the host PC, the clock loses
sync. I have to power down, and re-power-up the USRP2 for the clock to
lock onto my external source again. This is with the firmware/fpga from
svn r10441, and my host code. I've tried calling ->config_mimo and
- ->sync_to_pps() as soon as I create my USRP2 objects, but that didn't
seem to help.
Doug
- --
Doug Geiger
Research Assistant
Communications and Signal Processing Lab
Oklahoma State University
http://cspl.okstate.edu
address@hidden
address@hidden
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- [Discuss-gnuradio] Re: Re: Re: USRP2 and external clock (from GPS receiver), (continued)
Re: [Discuss-gnuradio] USRP2 and external clock (from GPS receiver), Douglas Geiger, 2009/02/19
- Re: [Discuss-gnuradio] USRP2 and external clock (from GPS receiver), Matt Ettus, 2009/02/19
- Re: [Discuss-gnuradio] USRP2 and external clock (from GPS receiver), Douglas Geiger, 2009/02/19
- Re: [Discuss-gnuradio] USRP2 and external clock (from GPS receiver), Matt Ettus, 2009/02/19
- Re: [Discuss-gnuradio] USRP2 and external clock (from GPS receiver), Douglas Geiger, 2009/02/19
- Re: [Discuss-gnuradio] USRP2 and external clock (from GPS receiver), Matt Ettus, 2009/02/19
- Re: [Discuss-gnuradio] USRP2 and external clock (from GPS receiver),
Douglas Geiger <=
- Re: [Discuss-gnuradio] USRP2 and external clock (from GPS receiver), Matt Ettus, 2009/02/20
- Re: [Discuss-gnuradio] USRP2 and external clock (from GPS receiver), Douglas Geiger, 2009/02/20
- Re: [Discuss-gnuradio] USRP2 and external clock (from GPS receiver), Douglas Geiger, 2009/02/20
- Re: [Discuss-gnuradio] USRP2 and external clock (from GPS receiver), Eric Blossom, 2009/02/20