Assembling the X300/X310 kit

Before you can start using your USRP, you might have to assemble the hardware, if this has not yet happened. Make sure you are grounded (e.g. by touching a radiator) in order not to damage sensitive electronics through static discharge!

1. Unscrew the top of your X300/X310 (there are 2 screws which can be easily loosened using a small Phillips screwdriver).
2. Insert the daughterboards by inserting them into the slots and optionally screwing them onto the motherboard.
3. Connect the RF connectors on the daughterboards to the front panel. In order to avoid confusion, make sure the internal connections match the labels on the front panel (i.e. TX/RX is connected to TX/RX).
4. If you have purchased an internal GPSDO, follow the instructions on the internal GPSDO manual page to insert the GPSDO. Note that you will need an external GPS antenna connected to the rear GPS ANT connector in order to make use of GPS, although your USRP will still be usable without.
5. Connect the 1 GigE SFP+ transceiver into the Ethernet port 0 and connect the X300/X310 with your computer.
6. Connect the power supply and switch on the USRP.

Network Connectivity

The next step is to make sure your computer can talk to the USRP. An otherwise unconfigured USRP device will have the IP address 192.168.10.2 when using 1GigE. It is recommended to directly connect your USRP to the computer at first, and to set the IP address on your machine to 192.168.10.1. See Section Setup the host interface on details how to change your machine's IP address.

Note: If you are running an automatic IP configuration service such as Network Manager, make sure it is either deactivated or configured to not change the network device! This can, in extreme cases, lead to you bricking the USRP!

If your network configuration is correct, running uhd_find_devices will find your USRP and print some information about it. You will also be able to ping the USRP by running:

ping 192.168.10.2

on the command line. At this point, you should also run:

uhd_usrp_probe --args addr=192.168.10.2

to make sure all of your components (daughterboards, GPSDO) are correctly detected and usable.

Updating the firmware

If the output from uhd_find_devices and uhd_usrp_probe didn't show any warnings, you can skip this step. However, if there were warnings regarding version incompatibility, you will have to upate the FPGA image before you can start using your USRP.

1. Download the current UHD images. You can use the uhd_images_downloader script provided with UHD (see also FPGA Image Flavors).

2. Use the usrp_x3xx_fpga_burner utility to update the FPGA image. On the command line, run:

   usrp_x3xx_fpga_burner --addr=192.168.10.2 --type=HGS # Since we are using 1GigE, type is HGS
   

If you have installed the images to a non-standard location, you might need to run (change the filename according to your device):

usrp_x3xx_fpga_burner --addr=192.168.10.2 --fpga-path <path_to_images>/usrp_x310_fpga_HGS.bit

The process of updating the firmware will take several minutes. Make sure the process of flashing the image does not get interrupted.

See Load the Images onto the On-board Flash for more details.

When your firmware is up to date, power-cycle the device and re-run uhd_usrp_probe. There should be no more warnings at this point, and all components should be correctly detected. Your USRP is now ready for development!

Gigabit Ethernet (1 GigE)

Ten Gigabit Ethernet (10 GigE)

PCI Express (Desktop)

Important Note: The USRP X-Series provides PCIe connectivity over MXI cable. We will use the 'MXI' nomenclature for the rest of this manual.

PCI Express (Laptop)

Important Note: The USRP X-Series provides PCIe connectivity over MXI cable. We will use the 'MXI' nomenclature for the rest of this manual.

FPGA Image Flavors

The USRP-X Series devices contains two SFP+ ports for the two Ethernet channels. Because the SFP+ ports support both 1 Gigabit (SFP) and 10 Gigabit (SFP+) transceivers, several FPGA images are shipped with UHD to determine the behavior of the above interfaces.

FPGA images are shipped in 2 formats:

• LVBITX: LabVIEW FPGA configuration bitstream format (for use over PCI Express and Ethernet)
• BIT: Xilinx configuration bitstream format (for use over Ethernet and JTAG)

To get the latest images, simply use the uhd_images_downloader script:

UNIX:

sudo uhd_images_downloader

Windows:

<path_to_python.exe> <install-path>/bin/uhd_images_downloader.py

Use PCI Express to load FPGA images

UHD requires a valid LabVIEW FPGA configuration bitstream file (LVBITX) to use the USRP-X Series device over the PCI Express bus. LabVIEW FPGA is NOT required to use UHD with a USRP-X Series device. Because FPGA configuration is a part of normal operation over PCI Express, there is no setup required before running UHD.

The fpga tag can be set in the optional device args passed to indicate the FPGA image flavor to UHD. If the above tag is specified, UHD will attempt to load the FPGA image with the requested flavor from the UHD images directory. If the tag is not specified, UHD will automatically detect the flavor of the image and attempt to load the corresponding configuration bitstream onto the device. Note that if UHD detects that the requested image is already loaded onto the FPGA then it will not reload it.

Use JTAG to load FPGA images

The USRP-X Series device features an on-board USB-JTAG programmer that can be accessed on the front-panel of the device. The iMPACT tool in the Xilinx Programming Tools package can be used to load an image over the JTAG interface. This can be useful for unbricking devices.

If you have iMPACT installed, you can use the impact_jtag_programmer.sh tool to install images. Make sure your X3x0 is powered on and connected to your computer using the front panel USB JTAG connector (USB 2.0 is fine for this). Then run the tool:

<path_to_uhd_tools>/impact_jtag_programmer.sh --fpga-path=<fpga_image_path>

Use the burner tool over Ethernet

Automatic FPGA path, detect image type:
usrp_x3xx_fpga_burner --addr=<IP address>

Automatic FPGA path, select image type:
usrp_x3xx_fpga_burner --addr=<IP address> --type=<HGS or XGS>

Manual FPGA path:
usrp_x3xx_fpga_burner --addr=<IP address> --fpga-path=<path to FPGA image>

Use the burner tool over PCI Express

Automatic FPGA path, detect image type:
usrp_x3xx_fpga_burner --resource=<NI-RIO resource>

Automatic FPGA path, select image type:
usrp_x3xx_fpga_burner --resource=<NI-RIO resource> --type=<HGS or XGS>

Manual FPGA path:
usrp_x3xx_fpga_burner --resource=<NI-RIO resource> --fpga-path=<path to FPGA image>

Device recovery and bricking

It is possible to put the device into an unusable state by loading bad images ("bricking"). Fortunately, the USRP-X Series device can be loaded with a good image temporarily using the USB-JTAG interface. Once booted into the safe image, the user can once again load images onto the device over Ethernet or PCI Express.

Setup the host interface

The USRP-X Series communicates at the IP/UDP layer over the Gigabit and Ten Gigabit Ethernet. The default IP address for the USRP X300/X310 device depends on the Ethernet Port and interface used. You must configure the host Ethernet interface with a static IP address on the same subnet as the connected device to enable communication, as shown in the following table:

On a Linux system, you can add a static IP address very easily by using the 'ip' command

sudo ip addr add 192.168.10.1/24 dev <interface>

Note that <interface> is usually something like eth0. You can discover the names of the network interfaces in your computer by running:

ip addr show

Note: When using UHD software, if an IP address for the USRP-X Series device is not specified, the software will use UDP broadcast packets to locate the USRP-X Series device. On some systems, the firewall will block UDP broadcast packets. It is recommended that you change or disable your firewall settings.

On many Linux distributions, NetworkManager or similar tools may control the network interface. It is important to deactivate these tools for your device before continuing!

Setting the MTU

As UHD by default uses receive and transmit frames larger than the standard MTU of 1500 Bytes, the NIC needs to be configured to use a larger MTU when used with the USRP X series devices.

sudo ip link set mtu 8192 dev <interface>

Upon initialization UHD will probe for the maximum possible path MTU along the path between the USRP X series device and the host, both in receive and transmit direction.

If the network hardware does not support MTUs as large as 8000 Bytes, passing the send_frame_size and receive_frame_size arguments will make UHD use smaller MTUs:

uhd_usrp_probe --args='send_frame_size=<max send MTU>, recv_frame_size=<max receive MTU>'

Note: This will most likely have a severe performance penalty.

Multiple devices per host

For maximum throughput, one Ethernet interface per USRP is recommended, although multiple devices may be connected via an Ethernet switch. In any case, each Ethernet interface should have its own subnet, and the corresponding USRP device should be assigned an address in that subnet. Example:

Configuration for USRP-X Series device 0:

• Ethernet interface IPv4 address: 192.168.10.1
• Ethernet interface subnet mask: 255.255.255.0
• USRP-X Series device IPv4 address: 192.168.10.2

Configuration for USRP-X Series device 1:

• Ethernet interface IPv4 address: 192.168.110.1
• Ethernet interface subnet mask: 255.255.255.0
• USRP-X Series device IPv4 address: 192.168.110.2

Change the USRP's IP address

You may need to change the USRP's IP address for several reasons:

• to satisfy your particular network configuration
• to use multiple USRP-X Series devices on the same host computer
• to set a known IP address into USRP (in case you forgot)

To change the USRP's IP address, you must know the current address of the USRP, and the network must be setup properly as described above. Run the following commands:

UNIX:

cd <install-path>/lib/uhd/utils
./usrp_burn_mb_eeprom --args=<optional device args> --key=ip-addr --val=192.168.10.3

Windows:

cd <install-path>\lib\uhd\utils
usrp_burn_mb_eeprom.exe --args=<optional device args> --key=ip-addr --val=192.168.10.3

Single device configuration

In a single-device configuration, the USRP device must have a unique IPv4 address on the host computer. The USRP can be identified through its IPv4 address, resolvable hostname, NI-RIO resource name or by other means. See the application notes on device identification. Use this addressing scheme with the multi_usrp interface (not a typo!).

Example device address string representation for a USRP-X Series device with IPv4 address 192.168.10.2:

addr=192.168.10.2

Example device address string representation for a USRP-X Series device with RIO resource name RIO0 over PCI Express:

resource=RIO0

Multiple device configuration

In a multi-device configuration, each USRP device must have a unique IPv4 address on the host computer. The device address parameter keys must be suffixed with the device index. Each parameter key should be of the format <key><index>. Use this addressing scheme with the multi_usrp interface.

• The order in which devices are indexed corresponds to the indexing of the transmit and receive channels.
• The key indexing provides the same granularity of device identification as in the single device case.

Example device address string representation for 2 USRPs with IPv4 addresses 192.168.10.2 and 192.168.20.2:

addr0=192.168.10.2, addr1=192.168.20.2

RuntimeError: no control response

This is a common error that occurs when you have set the subnet of your network interface to a different subnet than the network interface of the USRP device. For example, if your network interface is set to 192.168.20.1, and the USRP device is 192.168.10.2 (note the difference in the third numbers of the IP addresses), you will likely see a 'no control response' error message.

Fixing this is simple - just set the your host PC's IP address to the same subnet as that of your USRP device. Instructions for setting your IP address are in the previous section of this documentation.

Firewall issues

When the IP address is not specified, the device discovery broadcasts UDP packets from each Ethernet interface. Many firewalls will block the replies to these broadcast packets. If disabling your system's firewall or specifying the IP address yields a discovered device, then your firewall may be blocking replies to UDP broadcast packets. If this is the case, we recommend that you disable the firewall or create a rule to allow all incoming packets with UDP source port 49152.

Ping the device

The USRP device will reply to ICMP echo requests ("ping"). A successful ping response means that the device has booted properly and that it is using the expected IP address.

ping 192.168.10.2

USRP device not enumerated (Linux)

UHD requires the RIO device manager service to be running in order to communicate with an X-Series USRP over PCIe. This service is installed as a part of the USRP RIO (or NI-USRP) installer. On Linux, the service is not started at system boot time, and is left to the user to control. To start it, run the following command:

sudo niusrprio_pcie start

If the device still does not enumerate after starting the device manager, make sure that the host computer has successfully detected it. You can do so by running the following command:

lspci -k -d 1093:c4c4

A device similar to the following should be detected:

$ lspci -k -d 1093:c4c4
04:00.0 Signal processing controller: National Instruments ...
        Subsystem: National Instruments Device 76ca
        Kernel driver in use: niusrpriok_shipped

• A USRP X300 should appear with 'Subsystem: National Instruments Device 7736'
• A USRP X310 should appear with 'Subsystem: National Instruments Device 76ca'

USRP device not enumerated (Windows)

UHD requires the RIO device manager service to be running in order to communicate with an X-Series USRP over PCIe. This service is installed as a part of the USRP RIO (or NI-USRP) installer. On Windows, it can be found in the Services section in the Control Panel and it is started at system boot time. To ensure that the service is indeed started, navigate to the Services tag in the Windows Task Manager and ensure that the status of niusrpriorpc is "Running".

If the device still does not enumerate after starting the device manager, make sure that the host computer has successfully detected it. You can do so by checking if your device shows up in the Windows Device Manager.

Monitor the host network traffic

Use Wireshark to monitor packets sent to and received from the device.

Observe Ethernet port LEDs

When there is network traffic arriving at the Ethernet port, LEDs will light up. You can use this to make sure the network connection is correctly set up, e.g. by pinging the USRP and making sure the LEDs start to blink.

Front Panel

• JTAG: USB connector for the on-board USB-JTAG programmer
• RF A Group
  • TX/RX LED: Indicates that data is streaming on the TX/RX channel on daughterboard A
  • RX2 LED: Indicates that data is streaming on the RX2 channel on daughterboard A
• REF: Indicates that the external Reference Clock is locked
• PPS: Indicates a valid PPS signal by pulsing once per second
• AUX I/O: Front panel GPIO connector.
• GPS: Indicates that GPS reference is locked
• LINK: Indicates that the host computer is communicating with the device (Activity)
• RF B Group
  • TX/RX LED: Indicates that data is streaming on the TX/RX channel on daughterboard B
  • RX2 LED: Indicates that data is streaming on the RX2 channel on daughterboard B
• PWR: Power switch

Rear Panel

• PWR: Connector for the USRP-X Series power supply
• 1G/10G ETH: SFP+ ports for Ethernet interfaces
• REF OUT: Output port for the exported reference clock
• REF IN: Reference clock input
• PCIe x4: Connector for Cabled PCI Express link
• PPS/TRIG OUT: Output port for the PPS signal
• PPS/TRIG IN: Input port for the PPS signal
• GPS: Connection for the GPS antenna

Ref Clock - 10 MHz

Using an external 10 MHz reference clock, a square wave will offer the best phase noise performance, but a sinusoid is acceptable. The power level of the reference clock cannot exceed +15 dBm.

PPS - Pulse Per Second

Using a PPS signal for timestamp synchronization requires a square wave signal with the following a 5Vpp amplitude.

To test the PPS input, you can use the following tool from the UHD examples:

• <args> are device address arguments (optional if only one USRP device is on your machine)

cd <install-path>/lib/uhd/examples
./test_pps_input --args=<args>

Internal GPSDO

Please see the Internal GPSDO Application Notes for information on configuring and using the internal GPSDO.

Front Panel GPIO

Connector

Debugging custom FPGA designs with Xilinx Chipscope

Xilinx chipscope allows for debugging custom FPGA designs similar to a logic analyzer. USRP-X series devices can be used with Xilinx chipscope using the onboard USB JTAG connector.

Further information on how to use Chipscope can be found in the Xilinx Chipscope Pro Software and Cores User Guide (UG029).

Multiple RX channels

There are two complete DDC and DUC DSP chains in the FPGA. In the single channel case, only one chain is ever used. To receive from both channels, the user must set the RX or TX subdevice specification.

In the following example, a TVRX2 is installed. Channel 0 is sourced from subdevice RX1, and channel 1 is sourced from subdevice RX2 (RX1 and RX2 are antenna connectors on the TVRX2 daughterboard).

usrp->set_rx_subdev_spec("A:RX1 A:RX2");

Available Sensors

The following sensors are available for the USRP-X Series motherboards; they can be queried through the API.

• ref_locked - clock reference locked (internal/external)
• Other sensors are added when the GPSDO is enabled