Re: USRP2 Firmware Changes nt working properely?

Hi Tim,
           Actually just today i solved the problem of USRP2
synchronisation.
I downloaded the new firmware code from the gnuradio website did the
following changes by adding clocks_mimo_config(MC_WE_LOCK_TO_SMA);Â just
before the while loop, in the txrx.c compiled it and burnt in SD card.
Now the clocks are locked to reference clock and the USRP2’s are
synchronized, and everything is working well…!

But i have another issue, when i send the file containing complex I&Q
samples from GRC
Transmitter side : File Source —>USRP2_sink(interp=16, f=1.8G)
                       |–>FFT_sink(avg=yes)
                                           Â
Receiver side:Â usrp2_fftsink.py (decim=16,f=1.8G)

I get perfect frequency plot matching exactly as seen in the transmitter
side.

But when i use tx_samples.cc (interp=16, f=1.8G, -r)Â to transmit the
same file. I get the almost same frequency plot with lot of dissortion,
I have checked all the available parameters in the tx_samples.cc but in
vain.

I have also , python generated code top_block.py by the GRC for the
above function with the tx_samples.cc , both are sending 32bit floating
complex values to usrp2_sink…, how come their results are
different…? even though keeping all the parameters same for both of
them…!

Thank you
KRISHNA S

     Â

— On Tue, 30/3/10, Tim P. [email protected] wrote:

From: Tim P. [email protected]
Subject: Re: [Discuss-gnuradio] USRP2 Firmware Changes nt working
properely ???
To: “Krishna S” [email protected]
Date: Tuesday, 30 March, 2010, 8:05 PM

Hi Krishna,

(Sorry for the blank email before - accidently hit gmail shortcut)

The way I’ve done this in the past is by calling:

u=usrp2.source_32fc()
u.config_mimo(MC_WE_LOCK_TO_SMA)

in the Python flowgraph init. I’ve not had to modify the firmware to get
this to work (I cant remember if the firmware had to be modified to
confirm the clocks were synchronising via the test pin header on the
USRP2)

Cheers,

Tim

2010/3/30 Krishna S [email protected]

Hi i am trying to synchronize two USRP2’s to the reference clock 10MHz.
as per the discussions i found in the internet i have added

clocks_mimo_config(MC_WE_LOCK_TO_SMA);

just before the while(1) loopÂ
in txrx.c and then i have compiled the code to create txrx.bin

But when i burn this txrx.bin with the downloaded u2_rev3.bin from the
trunk(gnuradio website). The USRP2 is booting up all fine(6 LED’s flash
once and 2 LED’s remain). but when connected to PC , it shows USRP2 not
found.

to cross verify i also downloaded txrx.bin from the trunk in gnuradio
website and burnt the SD card with u2_rev3.bin. USRP2 again boots up
properely , and the USRP2 is detectable in the PC (./find_usrps)

But when i compile the firmware code and burn, the USRP2 boots properly
, but does not connect to the PC…I don’t know why ??? Can somebody
help me out here ? am i missing anything ?

I compiling the firmware directory in the gnuradio3.2.2/usrp2/firmwareÂ

the compiled txrx.bin is 28KB and the downloaded txrx.bin is 25.6KB

Thanks

KRISHNA S

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