I feel like I’ve seen this question asked before, but is it possible to
attach two USRP boards to the same PC, and transmit between the two?
-Michael F.-
On Fri, Jan 26, 2007 at 11:23:17AM -0600, Michael F. wrote:
I feel like I’ve seen this question asked before, but is it possible to
attach two USRP boards to the same PC, and transmit between the two?-Michael F.-
Yes it is.
The first argument to the usrp constructor, which, says which one you
want to open (0, 1, …). The interpretation of “which” is OS and
libusb
dependent and is kind of vague. Last time I checked, I believe that
it was a function of the order that the devices were connected.
Another approach is to open each one, then check the serial number to
see if it’s the one you want.
s = u.serial_number() # returns a string
Also note that the total USB bandwidth of the system (on the order of
32MB/s) is shared by all attached devices.
Eric
On Fri, Jan 26, 2007 at 06:49:54PM +0100, Raphaël Jacquot wrote:
want to open (0, 1, …). The interpretation of “which” is OS and libusb
unless you connect each to a separate port on the machine
in which case, you have a full bandwidth for each.
In almost all machines I have seen to date, there is a single EHCI
host controller that connects to all ports on the machine. The
bandwidth limit is the sum across all ports connected to a given EHCI
controller. (The one exception I have seen is a dual processor
Opteron motherboard based on an nVidia nForce4 chipset. It
effectively has two southbridge chips, each of which contains a USB
EHCI controller, SATA, etc).
You can determine how many ECHI controllers your machine has by
examining the output of lspci:
[eb@cyan ~]$ lspci | grep -i usb
00:1d.0 USB Controller: Intel Corporation 82801G (ICH7 Family) USB
UHCI #1 (rev 02)
00:1d.1 USB Controller: Intel Corporation 82801G (ICH7 Family) USB
UHCI #2 (rev 02)
00:1d.2 USB Controller: Intel Corporation 82801G (ICH7 Family) USB
UHCI #3 (rev 02)
00:1d.3 USB Controller: Intel Corporation 82801G (ICH7 Family) USB
UHCI #4 (rev 02)
00:1d.7 USB Controller: Intel Corporation 82801G (ICH7 Family) USB2
EHCI Controller (rev 02)
One EHCI controller and 4 associated UHCI controllers.
Eric