Re: [Discuss-gnuradio] UHD Announcement - July 6th 2010

[Josh Blum]

Zohair,

> 1- I am using a PC with four Ethernet ports. I burned the firmware and the
> fpga images created on 6-7-2010. Also, I tried assigning IP addresses from
> the same subnetwork: 192.168.10.X/24. However, Only a single USRP2 is
> discovered at a time while others are unreachable. (USRP2s IPs are also from
> the same subnetwork above)
>
> 2- Then I tried assigning IPs from 4 different subnetworks to the USRP2's,
> and all them  can be discovered normally. Is it possible that they work
> using IPs from the same subnetwork or not? (case 1)

The goal is to setup your networking on your such that all devices are 
accessible (ie your computer knows how to route udp/ip packets to the 
correct device based on ip address). The easiest way to use use a 
different subnet per ethernet card. 192.168.X.Y and burn each usrp with 
the corresponding address 192.168.X.Z. If you play around with subnet 
masks you can get other configurations.

> 3- I used a MIMO source with 4 outputs and the following settings:
> freq: 2414000000, 2414000000, 2414000000, 2414000000
> Arg: addr=192.168.10.11 192.168.20.11 192.168.30.11 192.168.40.11,
> recv_buff_size=50e6 50e6 50e6 50e6
> sample rate: 195.312K ( Firstly, I used 32K but at runtime I was prompted
> to use this value)

What you probably saw was a warning that the system could not 
automatically request a large enough buffer.

http://www.ettus.com/uhd_docs/manual/html/usrp2.html#os-specific-notes

Also, you can only specify one buffer size across all boards. If you 
think about it the setup should be uniform per board.

> Gain= 35,35,35,35
> Antennas= [‘RX2’, ‘RX2’, ‘RX2’, ‘RX2’]
>
> I connected the 4 outputs to graphic scopes but once I run the flowgraph, I
> see this error messages:
>
> terminate called after throwing an instance of
> 'boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::bad_lexical_cast>
> > '
>    what():  bad lexical cast: source type value could not be interpreted as
> target.

it cant cast a "50e6 50e6 50e6 50e6" to a double. I need to catch these 
error and throw meaning full exceptions. :-)

Thanks for asking, it seems that I need to add more to the docs and 
polish. -Josh