Re: [Discuss-gnuradio] some problems about usrp motherboard that i make by myself

[Eric Blossom]

On Sun, Jul 25, 2010 at 07:50:10PM -0700, tonygc wrote:
> 
> thank you for your reply, Eric! our team plans to integrate USRP with other
> functions, so we first want to copy the USRP motherboard to convince our PCB
> design. PCB has been tested, all is ok. after finishing the soldering, first
> load the firmware of FX2(with build_eeprom.py), then LEDs blinks. the
> daughterboard can be detected by Probe. but can't receive any signals,
> neither transmitting... is there something we omit? in addition, how to test
> whether FPGA image is loaded into FPGA?

There could be any number of things that you have omitted...

Either you, or somebody on your team will have to really understand
what is going on, how code is loaded into the FX2, how the fpga image
is loaded, etc, or you will have no hope of debugging this.

Once you have an understanding of what you expect to happen, then you
can look to see if it's happening.  If it is, good, go on to the next
thing.  If it isn't, then figure out why what you expect to be
happening isn't happening.


Suggested reading:  

  USB 2.0 Specification
  FX2 Technical Reference Manual
  The USRP schematics
  The source code for the FX2: usrp/firmware/*
  The source code for usrp/host/apps/usrper.cc
  The source code in usrp/host/*
  Datasheets for all parts on the board
  The FPGA source code

Eric



> Eric Blossom wrote:
> > 
> > On Wed, Jul 21, 2010 at 08:48:46PM -0700, tonygc wrote:
> >> 
> >> who can tell me the reason? any help will be appreciated... 
> > 
> > Bringing up new hardware (even if you think it's a perfect copy of
> > somebody else's design) is always a challenge.  It requires a wide
> > range of skills, patience, test equipment and the ability to figure
> > out how to debug a problem.
> > 
> > Most people I know learned these skills by working side-by-side at a
> > bench with people who had more experience than they did, both looking
> > at the same board...
> > 
> > A couple of things to check:
> > 
> >   Are the power supplies as expected?
> >   Do the clocks look good?
> >   Can you load code into the FX2?
> >   Can you load an FPGA image into the FPGA?
> >   ...
> >   
> > Good luck!
> > Eric
> > 
> > 
> > 
> >> tonygc wrote:
> >> > 
> >> > although there's no PCB of USRP motherboard, i make the PCB by myself.
> >> > there's no change of the motherboard, according to the schs. after
> >> > finishing the PCB and all components soldering, i burn the eeprom of
> >> the
> >> > motherboard by /gnuradio/usrp/firmware/src/usrp2/burn-usrp4-eeprom.
> >> > finally, its leds blinks. that's a small success for me. when i plug in
> >> > the rfx400 and run benchmark_tx.py, there's a sign that it's working
> >> > because it displays it's transmitting signals with
> >> > .......................... unfortunately, the receiver receives
> >> nothing...
> >> > then i use the probe to detect whether USRP works, and the probe
> >> displays
> >> > that it can detect the USRP and the daughterboard. it's the same as the
> >> > board bought from Ettus.  i'm confused. the daughterboard is also ok on
> >> > the USRP motherboard bought from Ettus. 
> >> > anyone can help me? i don't know how to deal with this problem... thank
> >> > you for your help!