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<div class="document" id="uhd-usrp2-and-n2x0-series-device-manual">
<h1 class="title">UHD - USRP2 and N2x0 Series Device Manual</h1>
<div class="contents topic" id="table-of-contents">
<p class="topic-title first">Table of Contents</p>
<ul class="simple">
<li><a class="reference internal" href="#comparative-features-list" id="id1">Comparative features list</a></li>
<li><a class="reference internal" href="#load-the-images-onto-the-sd-card-usrp2-only" id="id2">Load the Images onto the SD card (USRP2 only)</a><ul>
<li><a class="reference internal" href="#use-the-card-burner-tool-unix" id="id3">Use the card burner tool (UNIX)</a></li>
<li><a class="reference internal" href="#use-the-card-burner-tool-windows" id="id4">Use the card burner tool (Windows)</a></li>
</ul>
</li>
<li><a class="reference internal" href="#load-the-images-onto-the-on-board-flash-usrp-n-series-only" id="id5">Load the Images onto the On-board Flash (USRP-N Series only)</a><ul>
<li><a class="reference internal" href="#use-the-net-burner-tool" id="id6">Use the net burner tool</a></li>
<li><a class="reference internal" href="#use-the-graphical-net-burner-tool-linux" id="id7">Use the graphical net burner tool (Linux)</a></li>
<li><a class="reference internal" href="#use-the-graphical-net-burner-tool-windows" id="id8">Use the graphical net burner tool (Windows)</a></li>
<li><a class="reference internal" href="#device-recovery-and-bricking" id="id9">Device recovery and bricking</a></li>
</ul>
</li>
<li><a class="reference internal" href="#setup-networking" id="id10">Setup Networking</a><ul>
<li><a class="reference internal" href="#setup-the-host-interface" id="id11">Setup the host interface</a></li>
<li><a class="reference internal" href="#multiple-devices-per-host" id="id12">Multiple devices per host</a></li>
<li><a class="reference internal" href="#change-the-usrp2-s-ip-address" id="id13">Change the USRP2's IP address</a></li>
</ul>
</li>
<li><a class="reference internal" href="#communication-problems" id="id14">Communication Problems</a><ul>
<li><a class="reference internal" href="#runtimeerror-no-control-response" id="id15">RuntimeError: no control response</a></li>
<li><a class="reference internal" href="#firewall-issues" id="id16">Firewall issues</a></li>
<li><a class="reference internal" href="#ping-the-device" id="id17">Ping the device</a></li>
<li><a class="reference internal" href="#monitor-the-serial-output" id="id18">Monitor the serial output</a></li>
<li><a class="reference internal" href="#monitor-the-host-network-traffic" id="id19">Monitor the host network traffic</a></li>
</ul>
</li>
<li><a class="reference internal" href="#addressing-the-device" id="id20">Addressing the Device</a><ul>
<li><a class="reference internal" href="#single-device-configuration" id="id21">Single device configuration</a></li>
<li><a class="reference internal" href="#multiple-device-configuration" id="id22">Multiple device configuration</a></li>
</ul>
</li>
<li><a class="reference internal" href="#using-the-mimo-cable" id="id23">Using the MIMO Cable</a><ul>
<li><a class="reference internal" href="#shared-ethernet-mode" id="id24">Shared Ethernet mode</a></li>
<li><a class="reference internal" href="#dual-ethernet-mode" id="id25">Dual Ethernet mode</a></li>
<li><a class="reference internal" href="#configuring-the-slave" id="id26">Configuring the slave</a></li>
</ul>
</li>
<li><a class="reference internal" href="#alternative-stream-destination" id="id27">Alternative stream destination</a><ul>
<li><a class="reference internal" href="#set-the-subnet-and-gateway" id="id28">Set the subnet and gateway</a></li>
<li><a class="reference internal" href="#create-a-receive-streamer" id="id29">Create a receive streamer</a></li>
</ul>
</li>
<li><a class="reference internal" href="#hardware-setup-notes" id="id30">Hardware Setup Notes</a><ul>
<li><a class="reference internal" href="#front-panel-leds" id="id31">Front panel LEDs</a></li>
<li><a class="reference internal" href="#ref-clock-10-mhz" id="id32">Ref Clock - 10 MHz</a></li>
<li><a class="reference internal" href="#pps-pulse-per-second" id="id33">PPS - Pulse Per Second</a></li>
<li><a class="reference internal" href="#internal-gpsdo" id="id34">Internal GPSDO</a></li>
</ul>
</li>
<li><a class="reference internal" href="#miscellaneous" id="id35">Miscellaneous</a><ul>
<li><a class="reference internal" href="#available-sensors" id="id36">Available Sensors</a></li>
<li><a class="reference internal" href="#multiple-rx-channels" id="id37">Multiple RX channels</a></li>
</ul>
</li>
</ul>
</div>
<div class="section" id="comparative-features-list">
<h1>Comparative features list</h1>
<dl class="docutils">
<dt><strong>Hardware Capabilities:</strong></dt>
<dd><ul class="first last simple">
<li>1 transceiver card slot</li>
<li>External PPS reference input</li>
<li>External 10 MHz reference input</li>
<li>MIMO cable shared reference</li>
<li>Fixed 100 MHz clock rate</li>
<li>Internal GPSDO option (N2x0 only)</li>
</ul>
</dd>
<dt><strong>FPGA Capabilities:</strong></dt>
<dd><ul class="first last simple">
<li>2 RX DDC chains in FPGA</li>
<li>1 TX DUC chain in FPGA</li>
<li>Timed commands in FPGA (N2x0 only)</li>
<li>Timed sampling in FPGA</li>
<li>16-bit and 8-bit sample modes (sc8 and sc16)<ul>
<li>Up to 25 MHz of RF BW with 16-bit samples</li>
<li>Up to 50 MHz of RF BW with 8-bit samples</li>
</ul>
</li>
</ul>
</dd>
</dl>
</div>
<div class="section" id="load-the-images-onto-the-sd-card-usrp2-only">
<h1>Load the Images onto the SD card (USRP2 only)</h1>
<p><strong>Warning!</strong>
Use <strong>usrp2_card_burner</strong> with caution. If you specify the wrong device node,
you could overwrite your hard drive. Make sure that <strong>--dev=</strong> specifies the SD card.</p>
<p><strong>Warning!</strong>
It is possible to use 3rd party SD cards with the USRP2.
However, certain types of SD cards will not interface with the CPLD:</p>
<ul class="simple">
<li>Cards can be SDHC, which is not a supported interface.</li>
<li>Cards can have unexpected timing characteristics.</li>
</ul>
<p>For these reasons, we recommend that you use the SD card that was supplied with the USRP2.</p>
<div class="section" id="use-the-card-burner-tool-unix">
<h2>Use the card burner tool (UNIX)</h2>
<pre class="literal-block">
sudo <install-path>/lib/uhd/utils/usrp2_card_burner_gui.py
-- OR --
cd <install-path>/lib/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>
</pre>
<p>Use the <strong>--list</strong> 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.</p>
</div>
<div class="section" id="use-the-card-burner-tool-windows">
<h2>Use the card burner tool (Windows)</h2>
<pre class="literal-block">
<path_to_python.exe> <install-path>/lib/uhd/utils/usrp2_card_burner_gui.py
</pre>
</div>
</div>
<div class="section" id="load-the-images-onto-the-on-board-flash-usrp-n-series-only">
<h1>Load the Images onto the On-board Flash (USRP-N Series only)</h1>
<p>The USRP-N Series can be reprogrammed over the network to update or change the firmware and FPGA images.
When updating images, always burn both the FPGA and firmware images before power cycling.
This ensures that when the device reboots, it has a compatible set of images to boot into.</p>
<div class="section" id="use-the-net-burner-tool">
<h2>Use the net burner tool</h2>
<pre class="literal-block">
Use default images:
usrp_n2xx_simple_net_burner --addr=<IP address>
Use custom-built images:
usrp_n2xx_simple_net_burner --addr=<IP address> --fw=<firmware path> --fpga=<FPGA path>
</pre>
<p><strong>Note:</strong>
Different hardware revisions require different FPGA images.
Determine the revision number from the sticker on the rear of the chassis.
Use this number to select the correct FPGA image for your device.</p>
<p>For users who would prefer a graphical utility, a Python-based alternative exists.</p>
</div>
<div class="section" id="use-the-graphical-net-burner-tool-linux">
<h2>Use the graphical net burner tool (Linux)</h2>
<pre class="literal-block">
<install-path>/lib/uhd/utils/usrp_n2xx_net_burner_gui.py
</pre>
</div>
<div class="section" id="use-the-graphical-net-burner-tool-windows">
<h2>Use the graphical net burner tool (Windows)</h2>
<pre class="literal-block">
<path_to_python.exe> <install-path>/lib/uhd/utils/usrp_n2xx_net_burner_gui.py
</pre>
</div>
<div class="section" id="device-recovery-and-bricking">
<h2>Device recovery and bricking</h2>
<p>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.</p>
<p>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.</p>
<p>When in safe-mode, the USRP-N device will always have the IP address <strong>192.168.10.2</strong>.</p>
</div>
</div>
<div class="section" id="setup-networking">
<h1>Setup Networking</h1>
<p>The USRP2 only supports Gigabit Ethernet
and will not work with a 10/100 Mbps interface.
However, a 10/100 Mbps interface can be connected indirectly
to a USRP2 through a Gigabit Ethernet switch.</p>
<div class="section" id="setup-the-host-interface">
<h2>Setup the host interface</h2>
<p>The USRP2 communicates at the IP/UDP layer over the gigabit ethernet.
The default IP address of the USRP2 is <strong>192.168.10.2</strong>.
You will need to configure the host's Ethernet interface with a static IP
address to enable communication. An address of <strong>192.168.10.1</strong> and a subnet
mask of <strong>255.255.255.0</strong> is recommended.</p>
<p>On a Linux system, you can set a static IP address very easily by using the
'ifconfig' command:</p>
<pre class="literal-block">
sudo ifconfig <interface> 192.168.10.1
</pre>
<p>Note that <strong><interface></strong> is usually something like <strong>eth0</strong>. You can discover the
names of the network interfaces in your computer by running <strong>ifconfig</strong> without
any parameters:</p>
<pre class="literal-block">
ifconfig -a
</pre>
<p><strong>Note:</strong>
When using UHD software, 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.</p>
</div>
<div class="section" id="multiple-devices-per-host">
<h2>Multiple devices per host</h2>
<p>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:</p>
<p><strong>Configuration for USRP2 device 0:</strong></p>
<ul class="simple">
<li>Ethernet interface IPv4 address: <strong>192.168.10.1</strong></li>
<li>Ethernet interface subnet mask: <strong>255.255.255.0</strong></li>
<li>USRP2 device IPv4 address: <strong>192.168.10.2</strong></li>
</ul>
<p><strong>Configuration for USRP2 device 1:</strong></p>
<ul class="simple">
<li>Ethernet interface IPv4 address: <strong>192.168.20.1</strong></li>
<li>Ethernet interface subnet mask: <strong>255.255.255.0</strong></li>
<li>USRP2 device IPv4 address: <strong>192.168.20.2</strong></li>
</ul>
</div>
<div class="section" id="change-the-usrp2-s-ip-address">
<h2>Change the USRP2's IP address</h2>
<p>You may need to change the USRP2's IP address for several reasons:</p>
<ul class="simple">
<li>to satisfy your particular network configuration</li>
<li>to use multiple USRP2s on the same host computer</li>
<li>to set a known IP address into USRP2 (in case you forgot)</li>
</ul>
<p><strong>Method 1:</strong>
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:</p>
<pre class="literal-block">
cd <install-path>/lib/uhd/utils
./usrp_burn_mb_eeprom --args=<optional device args> --key=ip-addr --val=192.168.10.3
</pre>
<p><strong>Method 2 (Linux Only):</strong>
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:</p>
<pre class="literal-block">
cd <install-path>/lib/uhd/utils
sudo ./usrp2_recovery.py --ifc=eth0 --new-ip=192.168.10.3
</pre>
</div>
</div>
<div class="section" id="communication-problems">
<h1>Communication Problems</h1>
<p>When setting up a development machine for the first time,
you may have various difficulties communicating with the USRP device.
The following tips are designed to help narrow down and diagnose the problem.</p>
<div class="section" id="runtimeerror-no-control-response">
<h2>RuntimeError: no control response</h2>
<p>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 <strong>192.168.20.1</strong>, and the USRP device is
<strong>192.168.10.2</strong> (note the difference in the third numbers of the IP addresses), you
will likely see a 'no control response' error message.</p>
<p>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.</p>
</div>
<div class="section" id="firewall-issues">
<h2>Firewall issues</h2>
<p>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 <strong>49152</strong>.</p>
</div>
<div class="section" id="ping-the-device">
<h2>Ping the device</h2>
<p>The USRP device 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.</p>
<pre class="literal-block">
ping 192.168.10.2
</pre>
</div>
<div class="section" id="monitor-the-serial-output">
<h2>Monitor the serial output</h2>
<p>Read the serial port to get debug verbose output 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 <strong>GND</strong> to the converter ground, and connect <strong>TXD</strong> to the converter receive.
The <strong>RXD</strong> pin can be left unconnected as this is only a one-way communication.</p>
<ul class="simple">
<li><strong>USRP2:</strong> Serial port located on the rear edge</li>
<li><strong>N210:</strong> Serial port located on the left side</li>
</ul>
</div>
<div class="section" id="monitor-the-host-network-traffic">
<h2>Monitor the host network traffic</h2>
<p>Use Wireshark to monitor packets sent to and received from the device.</p>
</div>
</div>
<div class="section" id="addressing-the-device">
<h1>Addressing the Device</h1>
<div class="section" id="single-device-configuration">
<h2>Single device configuration</h2>
<p>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
<a class="reference external" href="./identification.html">device identification</a>. Please note that this
addressing scheme should also be used with the <strong>multi_usrp</strong> interface.</p>
<p>Example device address string representation for a USRP2 with IPv4 address <strong>192.168.10.2</strong>:</p>
<pre class="literal-block">
addr=192.168.10.2
</pre>
</div>
<div class="section" id="multiple-device-configuration">
<h2>Multiple device configuration</h2>
<p>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 <strong>multi_usrp</strong> interface.</p>
<ul class="simple">
<li>The order in which devices are indexed corresponds to the indexing of the transmit and receive channels.</li>
<li>The key indexing provides the same granularity of device identification as in the single device case.</li>
</ul>
<p>Example device address string representation for 2 USRP2s with IPv4 addresses <strong>192.168.10.2</strong> and <strong>192.168.20.2</strong>:</p>
<pre class="literal-block">
addr0=192.168.10.2, addr1=192.168.20.2
</pre>
</div>
</div>
<div class="section" id="using-the-mimo-cable">
<h1>Using the MIMO Cable</h1>
<p>The MIMO cable allows two USRP devices to share reference clocks,
time synchronization, and the Ethernet interface.
One of the devices will sync its clock and time references to the MIMO cable.
This device will be referred to as the slave, and the other device, the master.</p>
<ul class="simple">
<li>The slave device acquires the clock and time references from the master device.</li>
<li>The master and slave may be used individually or in a multi-device configuration.</li>
<li>External clocking is optional and should only be supplied to the master device.</li>
</ul>
<div class="section" id="shared-ethernet-mode">
<h2>Shared Ethernet mode</h2>
<p>In shared Ethernet mode,
only one device in the configuration can be attached to the Ethernet.</p>
<ul class="simple">
<li>Clock reference, time reference, and data are communicated over the MIMO cable.</li>
<li>Master and slave must have different IPv4 addresses in the same subnet.</li>
</ul>
</div>
<div class="section" id="dual-ethernet-mode">
<h2>Dual Ethernet mode</h2>
<p>In dual Ethernet mode,
both devices in the configuration must be attached to the Ethernet.</p>
<ul class="simple">
<li>Only clock reference and time reference are communicated over the MIMO cable.</li>
<li>The master and slave must have different IPv4 addresses in different subnets.</li>
</ul>
</div>
<div class="section" id="configuring-the-slave">
<h2>Configuring the slave</h2>
<p>In order for the slave to synchronize to the master over MIMO cable,
the following clock configuration must be set on the slave device:</p>
<pre class="literal-block">
usrp->set_time_source("mimo", slave_index);
usrp->set_clock_source("mimo", slave_index);
</pre>
</div>
</div>
<div class="section" id="alternative-stream-destination">
<h1>Alternative stream destination</h1>
<p>It is possible to program the USRP device to send RX packets to an alternative IP/UDP destination.</p>
<div class="section" id="set-the-subnet-and-gateway">
<h2>Set the subnet and gateway</h2>
<p>To use an alternative streaming destination,
the device needs to be able to determine if the destination address
is within its subnet, and ARP appropriately.
Therefore, the user should ensure that subnet and gateway addresses
have been programmed into the device's EEPROM.</p>
<p>Run the following commands:</p>
<pre class="literal-block">
cd <install-path>/lib/uhd/utils
./usrp_burn_mb_eeprom --args=<optional device args> --key=subnet --val=255.255.255.0
./usrp_burn_mb_eeprom --args=<optional device args> --key=gateway --val=192.168.10.1
</pre>
</div>
<div class="section" id="create-a-receive-streamer">
<h2>Create a receive streamer</h2>
<p>Set the stream args "addr" and "port" values to the alternative destination.
Packets will be sent to this destination when the user issues a stream command.</p>
<pre class="literal-block">
//create a receive streamer, host type does not matter
uhd::stream_args_t stream_args("fc32");
//resolvable address and port for a remote udp socket
stream_args.args["addr"] = "192.168.10.42";
stream_args.args["port"] = "12345";
//create the streamer
uhd::rx_streamer::sptr rx_stream = usrp->get_rx_stream(stream_args);
//issue stream command
uhd::stream_cmd_t stream_cmd(uhd::stream_cmd_t::STREAM_MODE_NUM_SAMPS_AND_DONE);
stream_cmd.num_samps = total_num_samps;
stream_cmd.stream_now = true;
usrp->issue_stream_cmd(stream_cmd);
</pre>
<p><strong>Note:</strong>
Calling recv() on this streamer object should yield a timeout.</p>
</div>
</div>
<div class="section" id="hardware-setup-notes">
<h1>Hardware Setup Notes</h1>
<div class="section" id="front-panel-leds">
<h2>Front panel LEDs</h2>
<p>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:</p>
<ul class="simple">
<li><strong>LED A:</strong> transmitting</li>
<li><strong>LED B:</strong> MIMO cable link</li>
<li><strong>LED C:</strong> receiving</li>
<li><strong>LED D:</strong> firmware loaded</li>
<li><strong>LED E:</strong> reference lock</li>
<li><strong>LED F:</strong> CPLD loaded</li>
</ul>
</div>
<div class="section" id="ref-clock-10-mhz">
<h2>Ref Clock - 10 MHz</h2>
<p>Using an external 10 MHz reference clock, a square wave will offer the best phase
noise performance, but a sinusoid is acceptable. The reference clock requires the following power level:</p>
<ul class="simple">
<li><strong>USRP2</strong> 5 to 15 dBm</li>
<li><strong>N2XX</strong> 0 to 15 dBm</li>
</ul>
</div>
<div class="section" id="pps-pulse-per-second">
<h2>PPS - Pulse Per Second</h2>
<p>Using a PPS signal for timestamp synchronization requires a square wave signal with the following amplitude:</p>
<ul class="simple">
<li><strong>USRP2</strong> 5Vpp</li>
<li><strong>N2XX</strong> 3.3 to 5Vpp</li>
</ul>
<p>Test the PPS input with the following app:</p>
<ul class="simple">
<li><strong><args></strong> are device address arguments (optional if only one USRP device is on your machine)</li>
</ul>
<pre class="literal-block">
cd <install-path>/lib/uhd/examples
./test_pps_input --args=<args>
</pre>
</div>
<div class="section" id="internal-gpsdo">
<h2>Internal GPSDO</h2>
<p>Please see the <a class="reference external" href="./gpsdo.html">Internal GPSDO Application Notes</a>
for information on configuring and using the internal GPSDO.</p>
</div>
</div>
<div class="section" id="miscellaneous">
<h1>Miscellaneous</h1>
<div class="section" id="available-sensors">
<h2>Available Sensors</h2>
<p>The following sensors are available for the USRP2/N-Series motherboards;
they can be queried through the API.</p>
<ul class="simple">
<li><strong>mimo_locked</strong> - clock reference locked over the MIMO cable</li>
<li><strong>ref_locked</strong> - clock reference locked (internal/external)</li>
<li>other sensors are added when the GPSDO is enabled</li>
</ul>
</div>
<div class="section" id="multiple-rx-channels">
<h2>Multiple RX channels</h2>
<p>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 <strong>RX</strong> subdevice specification.
This hardware has only one daughterboard slot,
which has been aptly named slot <strong>A</strong>.</p>
<p>In the following example, a TVRX2 is installed.
Channel 0 is sourced from subdevice <strong>RX1</strong>,
and channel 1 is sourced from subdevice <strong>RX2</strong> (<strong>RX1</strong> and <strong>RX2</strong>
are the antenna ports on the TVRX2 daughterboard):</p>
<pre class="literal-block">
usrp->set_rx_subdev_spec("A:RX1 A:RX2");
</pre>
</div>
</div>
</div>
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