Re: [Discuss-gnuradio] saturation with multi_fft.py

[Martin Dvh]

Eric Blossom wrote:
> On Tue, Oct 09, 2007 at 12:05:08AM -0400, address@hidden wrote:
>> Your suggestion worked to fix the compilation problem, along with the 
>> addition of a line for atr_delay.v, however, I'm not able to load the 
>> newly compiled rbf file into the usrp, and the error leads me to believe I 
>> need to take a step back and make sure I'm working with the right files.
>>
>> When I copied the newly compiled usrp_multi.rbf to 
>> share/usrp/rev2/, I get the following error with the 
>> verbose environment variable turned on:
>>
>> usrp: firmware ...share/usrp/rev2/std.ihx loaded successfully.
>> Can't find fpga bitstream: multi_usrp_test.rbf
>>
>> even though I specified the name "multi_usrp_test.rbf" in the python code.
>>
>> So on a hunch I changed the name of the rbf file to std_4rx_0tx.rbf, 
>> adjusted my python code appropriatly, and now it loads but I get the 
>> following:
>>
>> usrp: firmware .../share/usrp/rev2/std.ihx loaded successfully.
>> usrp: fpga bitstream ...share/usrp/rev2/std_4rx_0tx.rbf loaded successfully.
>> This code requires an FPGA build with 4 DDCs.  This FPGA has only 2.
> 
> This would indicate that you didn't build what you think you did (or
> that the code that initializes that register value is hosed).
> The host reads back a register from the FPGA image to get the answer
> to number DDCs and DUCs.  I suspect that you may have copied the wrong
> rbf to the wrong place, or something similar.
> 
>> So now my question is, to test the multiple receive capability of the 
>> usrp,
> 
> Just to be clear, I think that you mean that you want to use multiple
> USRPs to receive multiple signals, NOT a single USRP with two
> daughterboards to receive multiple signals.  Do I understand you correctly?
> 
>> exactly which project file (in which directory) do I need to load 
>> into Quartus, do I need to modify it to enable 4 receive ddc's, and once 
>> it compiles, what do I do with it?  Where do I put it and how do I name 
>> it?  Why does it need to be named exactly one way and not another?
> 
> The project file for the multi-usrp stuff is in
> usrp/fpga/toplevel/usrp_multi
> 
> You need to copy the resulting .rbf file into 
> .../share/usrp/rev{2,4}/multi_4rx_0tx.rbf (or whatever you want to call it)
> 
> Then you need to ensure that you are specifying that filename in the
> USRP constructor.  E.g.,
> 
>   u = usrp.source_c(0, decim, fpga_firmware="multi_4rx_0tx.rbf")
> 
> I'm assuming that you have looked at the code in
> gnuradio-examples/python/multi_usrp/*
> 
> I'm not exactly sure of that status of that code.  
> Martin DVH would be the one to ask.
That code hasn't been updated in a while.
usrp_mult/config.vh includes
`include "../include/common_config_2rxhb_2tx.vh"

Which enables two actual rx and two actual tx channels.
So the default bitstream it generates should be renamed to multi_2rxhb_2tx.rbf

>> This code requires an FPGA build with 4 DDCs.  This FPGA has only 2.
The code does a few tricks to enable 4 rx channels to enable extra channels for 
sample alignment.
(These extra channels don't carry samples but just samplenumbers)

Is seems like somewhere in the codechain a check was added (or changed) to 
check if the bitstream supports the number of channels requested.
Probably there goes something wrong there.

(usrp_multi has two actual channels a samplenumberchannel and a not-used 
channel)

Martin
> 
> Eric
> 
> 
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