Use the card burner tool (unix)

sudo <install-path>/share/uhd/utils/usrp2_card_burner_gui.py

-- OR --

cd <install-path>/share/uhd/utils
sudo ./usrp2_card_burner.py --dev=/dev/sd<XXX> --fpga=<path_to_fpga_image>
sudo ./usrp2_card_burner.py --dev=/dev/sd<XXX> --fw=<path_to_firmware_image>

Use the --list option to get a list of possible raw devices. The list result will filter out disk partitions and devices too large to be the sd card. The list option has been implemented on Linux, Mac OS X, and Windows.

Use the card burner tool (windows)

<path_to_python.exe> <install-path>/share/uhd/utils/usrp2_card_burner_gui.py

Use the net burner tool (unix)

sudo <install-path>/share/uhd/utils/usrp_n2xx_net_burner_gui.py

-- OR --

cd <install-path>/share/uhd/utils
./usrp_n2xx_net_burner.py --addr=<ip address> --fw=<path for firmware image>
./usrp_n2xx_net_burner.py --addr=<ip address> --fpga=<path to FPGA image>

Use the net burner tool (Windows)

<path_to_python.exe> <install-path>/share/uhd/utils/usrp_n2xx_net_burner_gui.py

Device recovery and bricking

Its possible to put the device into an unusable state by loading bad images. Fortunately, the USRP-N Series can be booted into a safe (read-only) image. Once booted into the safe image, the user can once again load images onto the device.

The safe-mode button is a pushbutton switch (S2) located inside the enclosure. To boot into the safe image, hold-down the safe-mode button while power-cycling the device. Continue to hold-down the button until the front-panel LEDs blink and remain solid.

When in safe-mode, the USRP-N device will always have the IP address 192.168.10.2

Setup the host interface

The USRP2 communicates at the IP/UDP layer over the gigabit ethernet. The default IP address of the USRP2 is 192.168.10.2 You will need to configure the host's ethernet interface with a static IP address to enable communication. An address of 192.168.10.1 and a subnet mask of 255.255.255.0 is recommended.

Note: When using the UHD, if an IP address for the USRP2 is not specified, the software will use UDP broadcast packets to locate the USRP2. On some systems, the firewall will block UDP broadcast packets. It is recommended that you change or disable your firewall settings.

Multiple devices per host

For maximum throughput, one ethernet interface per USRP2 is recommended, although multiple devices may be connected via a gigabit ethernet switch. In any case, each ethernet interface should have its own subnet, and the corresponding USRP2 device should be assigned an address in that subnet. Example:

Configuration for USRP2 device 0:

• Ethernet interface IPv4 address: 192.168.10.1
• Ethernet interface subnet mask: 255.255.255.0
• USRP2 device IPv4 address: 192.168.10.2

Configuration for USRP2 device 1:

• Ethernet interface IPv4 address: 192.168.20.1
• Ethernet interface subnet mask: 255.255.255.0
• USRP2 device IPv4 address: 192.168.20.2

Change the USRP2's IP address

You may need to change the USRP2's IP address for several reasons:

• to satisfy your particular network configuration
• to use multiple USRP2s on the same host computer
• to set a known IP address into USRP2 (in case you forgot)

Method 1: To change the USRP2's IP address you must know the current address of the USRP2, and the network must be setup properly as described above. Run the following commands:

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

Method 2 (Linux Only): This method assumes that you do not know the IP address of your USRP2. It uses raw ethernet packets to bypass the IP/UDP layer to communicate with the USRP2. Run the following commands:

cd <install-path>/share/uhd/utils
sudo ./usrp2_recovery.py --ifc=eth0 --new-ip=192.168.10.3

Firewall issues

When the IP address is not specified, the device discovery sends broadcast 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 yeilds 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 will reply to icmp echo requests. 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

Monitor the serial output

Read the serial port to get debug verbose from the embedded microcontroller. The microcontroller prints useful information about IP addresses, MAC addresses, control packets, fast-path settings, and bootloading. Use a standard USB to 3.3v-level serial converter at 230400 baud. Connect GND to the converter ground, and connect TXD to the converter receive. The RXD pin can be left unconnected as this is only a one-way communication.

• USRP2: Serial port located on the rear edge
• N210: Serial port located on the left side

Monitor the host network traffic

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

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, or by other means. See the application notes on device identification. Use this addressing scheme with the single_usrp interface.

Example device address string representation for a USRP2 with IPv4 address 192.168.10.2

addr=192.168.10.2

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 USRP2s with IPv4 addresses 192.168.10.2 and 192.168.20.2

addr0=192.168.10.2, addr1=192.168.20.2

Shared ethernet mode

In shared ethernet mode, only one device in the configuration can be attached to the ethernet.

• Clock reference, time reference, and data are communicated over the MIMO cable.
• Both master and slave must have different IPv4 addresses in the same subnet.

Dual ethernet mode

In dual ethernet mode, both devices in the configuration must be attached to the ethernet.

• Only clock reference and time reference are communicated over the MIMO cable.
• Both master and slave must have different IPv4 addresses in different subnets.

Configuring the slave

In order for the slave to synchronize to the master over MIMO cable, the following clock configuration must be set on the slave device:

uhd::clock_config_t clock_config;
clock_config.ref_source = uhd::clock_config_t::REF_MIMO;
clock_config.pps_source = uhd::clock_config_t::PPS_MIMO;
usrp->set_clock_config(clock_config, slave_index);

Front panel LEDs

The LEDs on the front panel can be useful in debugging hardware and software issues. The LEDs reveal the following about the state of the device:

• LED A: transmitting
• LED B: mimo cable link
• LED C: receiving
• LED D: firmware loaded
• LED E: reference lock
• LED F: CPLD loaded

Ref Clock - 10MHz

Using an external 10MHz reference clock, square wave will offer the best phase noise performance, but sinusoid is acceptable. The reference clock requires the following power level:

• USRP2 5 to 15dBm
• N2XX 0 to 15dBm

PPS - Pulse Per Second

Using a PPS signal for timestamp synchronization requires a square wave signal with the following amplitude:

• USRP2 5Vpp
• N2XX 3.3 to 5Vpp

Test the PPS input with the following app:

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

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

Internal GPSDO

Please see the GPSDO application note for information on configuring and using the internal GPSDO.

Installation instructions:

1. Remove the daughterboard.
2. Move J510 jumper on the motherboard from 1-2 to 2-3 in order to switch from external 10 MHz Ref Clock to GPSDO’s 10 MHz Ref Clock
3. Screw the GPSDO module in place with the screws provided. The screws are treated to avoid loosening with vibration.
4. Connect the GPSDO power cable to J509 on the motherboard, and then to connector D on the GPSDO module
5. Connect an SMB to SMA cable between connectors B and J506 (PPS2)
6. Connect an SMB to SMA cable between connectors C and J507 (CLK REF2)
7. Connect the serial cable between connectors A and J312 (RS232-3) on the motherboard. If J312 on your USRP isn’t a keyed connector, please ensure to connect pin1 (TX) of connector A to pin3 (RX) on J312.
8. Remove the washer and nut from the MMCX to SMA-Bulkhead cable. Connect it to connector E and then insert SMA-Bulkhead connector through the hole in the rear panel. Tighten nut to fasten in place.
9. Replace the daughterboard pushing all the cables underneath.

Then run the following commands:

cd <install-path>/share/uhd/utils
./usrp_burn_mb_eeprom --args=<optional device args> --key=gpsdo --val=internal

Removal instructions:

Restore the jumper setting, disconnect the cables, and unscrew the GPSDO unit. Then run the following commands:

cd <install-path>/share/uhd/utils
./usrp_burn_mb_eeprom --args=<optional device args> --key=gpsdo --val=none

Antenna Types:

The GPSDO is capable of supplying a 3V for active GPS antennas or supporting passive antennas

Available Sensors

The following sensors are available for the USRP2/N-Series motherboards; they can be queried through the API.

• mimo_locked - clock reference locked over the MIMO cable
• ref_locked - clock reference locked (internal/external)
• gps_time - GPS epoch seconds (available when GPSDO installed)
• gps_locked - GPS lock status

Multiple RX channels

There are two complete DDC 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 subdevice specification. This hardware has only one daughterboard slot, which has been aptly named slot "A".

In the following example, a TVRX2 is installed. Channel 0 is sourced from subdevice RX1, channel 1 is sourced from subdevice RX2:

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