N300/N310 Getting Started Guides

Kit Contents

N310

USRP N300/N310 DC Power Supply (12V, 7A) 1 RJ45 – SFP+ Adapter 1 Gigabit Ethernet Cat-5e Cable (3m) USB-A to Micro USB-B Cable (1m) Getting Started Guide Ettus Research Sticker

Verify the Contents of Your Kit

Ensure that your kit contains all the items listed above. If any items are missing, please contact sales@ettus.com​ immediately.

You Will Need

• For Network Mode: A host computer with an available 1 or 10 Gigabit Ethernet interface for sample streaming.
• For Stand-Alone Embedded Mode: A host computer with an available 1 Gigabit Ethernet port or a USB 2.0 port to remotely access the embedded Linux operating system running on ARM CPU.

Proper Care and Handling

All Ettus Research products are individually tested before shipment. The USRP is guaranteed to be functional at the time it is received by the customer. Improper use or handling of the USRP can cause the device to become non-functional. Take the following precautions to prevent damage to the unit.

• Never allow metal objects to touch the circuit board while powered.
• Always properly terminate the transmit port with an antenna or 50Ω load.
• Always handle the board with proper anti-static methods.
• Never allow the board to directly or indirectly come into contact with any voltage spikes.
• Never allow any water or condensing moisture to come into contact with the device.
• Always use caution with FPGA, firmware, or software modifications.

	Never apply more than -15 dBm of power into any RF input.
	Always use at least 30dB attenuation if operating in loopback configuration

Install and Setup the Software Tools on Your Host Computer

In order to use your Universal Software Radio Peripheral (USRP™), you must have the software tools correctly installed and configured on your host computer. A step-by-step guide for doing this is available at the Building and Installing the USRP Open-Source Toolchain (UHD and GNU Radio) on Linux, OS X and Windows Application Notes. See the Hardware Specifications section of the USRP N300 Series Hardware Resources page for additional details on which version of the USRP Hardware Driver, UHD, is required. It is recommended to use the latest stable version of UHD that is available.

If you have a USB stick with the Live SDR Environment installed on it, then you may boot your host computer from that. The LiveUSB SDR Environment does not require anything to be installed on your host computer, and contains a Linux-based environment with the UHD software and the GNU Radio framework already installed. More information about the Live SDR Environment is available at the Live SDR Environment Getting Started Guides page.

The USRP N300/N310 requires UHD version 3.11.0.0 or later. Ettus recommends using the latest stable version of UHD. Please consult the UHD Manual at ​[1] for more details on device-specific software features.

Connecting the Device

Powering on for the First Time

You can connect the device to your host computer in the following ways:

• Using the on-board serial-to-USB connector.
• Using the RJ-45 Ethernet port and an SSH client on your host computer.

To power on the device for the first time, connect the host computer to the device using the USB cable. This setup allows you to review and modify the network configuration of the device and interact with the bootloader in case of problems during the boot process.

Setting up a Serial Connection

It is possible to gain root access to the device using a serial terminal emulator. Most Linux, OSX, or other Unix flavours have a tool called screen which can be used for this purpose, by running the following command: sudo screen /dev/ttyUSB2 115200 In this command, we prepend sudo to elevate user privileges (by default, accessing serial ports is not available to regular users), we specify the device node, in this case, /dev/ttyUSB2, and the baud rate 115200.

The exact device node depends on your operating system's driver and other USB devices that might be already connected. Modern Linux systems offer alternatives to simply trying device nodes; instead, the OS might have a directory of symlinks under /dev/serial/by-id:

   $ ls /dev/serial/by-id
   usb-Digilent_Digilent_USB_Device_25163511FE00-if00-port0
   usb-Digilent_Digilent_USB_Device_25163511FE00-if01-port0
   usb-Silicon_Labs_CP2105_Dual_USB_to_UART_Bridge_Controller_007F6CB5-if00-port0
   usb-Silicon_Labs_CP2105_Dual_USB_to_UART_Bridge_Controller_007F6CB5-if01-port0

Note: Exact names depend on the host operating system version and may differ.

Every N3XX series device connected to USB will by default show up as four different devices. The devices labeled "USB_to_UART_Bridge_Controller" are the devices that offer a serial prompt. The first (with the if00 suffix) connects to Linux, whereas the second connects to the STM32 microcontroller. If you have multiple N3XX devices connect, you may have to try out multiple devices. In this case, to use this symlink instead of the raw device node address, modify the command above to:

   $ sudo screen /dev/serial/by-id/usb-Silicon_Labs_CP2105_Dual_USB_to_UART_Bridge_Controller_007F6CB5-if00-port0 115200

Boot messages will appear and update rapidly after you power on the device. Once the boot process successfully completes, a login prompt like the following should appear:

   ni-3xx-<motherboard serial #>:

Enter the username ​root​ and leave the password field blank.

You should be presented with a shell prompt similar to the following:

   root@ni-n3xx-<motherboard serial #>:~#

You should be presented with a shell prompt similar to the following:

On this prompt, you can enter any Linux command available. Using the default configuration, the serial console will also show all kernel log messages (unlike when using SSH, for example), and give access to the boot loader (U-boot prompt). This can be used to debug kernel or bootloader issues more efficiently than when logged in via SSH.

Connecting to the microcontroller

The STM32 microcontroller (which controls the power sequencing, among other things) also has a serial console available. To connect to the microcontroller, use the other UART device. In the example above:

   $ sudo screen /dev/serial/by-id/usb-Silicon_Labs_CP2105_Dual_USB_to_UART_Bridge_Controller_007F6CB5-if01-port0 115200

It provides a very simple prompt. The command 'help' will list all available commands. A direct connection to the microcontroller can be used to hard-reset the device without physically accessing it (i.e., emulating a power button press) and other low-level diagnostics.

Configuring an SSH Connection

The device relies on the DHCP protocol to automatically obtain an IP address when connected over the RJ45 1 Gigabit Ethernet port. If your network setup does not include a DHCP server, refer to the ​Serial Connection​ section above or configure a DHCP server on the network to provide an IP address to the device.

After the device has obtained an IP address, you can remotely log into it from a Linux or macOS system with SSH, as shown below:

   $ ssh root@192.168.1.x

NOTE: The IP address may vary depending on your network setup.

On Microsoft Windows, the connection can be established using ​Putty​. Enter the IP address of the device and the username ​root. The password field should be left blank.

You should be presented with a shell like the following:

   root@ni-n3xx-<motherboard serial #>:~#

Find more details on network configuration here: https://files.ettus.com/manual/page_usrp_n3xx.html#n3xx_network_configuration

Setting Up a Streaming Connection

The device supports multiple, high-speed, low-latency interfaces on the SFP+ ports for streaming samples to the host computer. Complete the steps below to set up a streaming connection over the 1 Gigabit Ethernet interface on the SFP+ port.

1. Configure your Host's Ethernet adapter as shown below:

   IP Address: 192.168.10.1
   Subnet Mask: 255.255.255.0
   Gateway: 0.0.0.0

2. Insert the ​ RJ45 – SFP+ adapter ​into​ SFP Port 0​ .

3. Connect the adapter to a host computer using the Ethernet cable.

The ​ Green LED​ above ​SFP Port 0​ should illuminate.

4. To test the connection,​ ​ping​ the device at address 192.168.10.2​ from the host, as shown below:

   $ ping 192.168.10.2

For more details on Network Setup and Configuration, please see the “Interfaces and Connectivity” section on the N300/N310 hardware resources page located within the Ettus Research Knowledge Base at ​https://kb.ettus.com/N300/N310​ .

Verifying Device Operation

Once the UHD driver is installed on the host computer, verify the correct operation of the device by running the various utility programs included in the driver. Refer to the Application Note Verifying the Operation of the USRP Using UHD and GNU Radio.

Upgrading to 10 Gigabit Ethernet

The device also supports dual 10 Gigabit Ethernet connections. To use these interfaces, we recommend our 10 Gigabit Ethernet Connectivity kit. For more information on this accessory, visit https://www.ettus.com/product/details/10GIGE-KIT​. For more information on using the 10 Gigabit Ethernet interface, refer to N300/N310 Hardware Resources Page.

Updating the Filesystem

Before doing any major work with a newly acquired USRP N300/N310, it is recommended to update the file system. Updating the filesystem can be accomplished directly on the N300/N310 by using Mender or externally by manually writing an image onto a micro SD card and inserting it. While manual updating is faster, Mender requires no direct physical access to the device. For details on using Mender, see Section Mender: Remote update capability.

Manual updating is simply loading an image on the micro SD card. The first step in that process is to obtain an image.

To obtain the default micro SD card image for a specific version of UHD, install that version of UHD (3.11.0.1 or later) on a host system with Internet access and run:

   $ uhd_images_downloader -t n3xx_common_sdimg_default

The image will be downloaded to <UHD_INSTALL_DIR>/share/uhd/images/usrp_n3xx_fs.sdimg, where UHD_INSTALL_DIR is the UHD installation directory.

To load an image onto the micro SD card, connect the card to the host and run:

   $ sudo dd if=<YOUR_IMAGE> of=/dev/<YOUR_SD_CARD> bs=1M

The <YOUR_IMAGE> is the path to the micro SD card image (i.e.<UHD_INSTALL_DIR>/share/uhd/images/usrp_n3xx_fs.sdimg).

The <YOUR_SD_CARD> device node depends on your operating system and which other devices are plugged in. Typical values are sdb or mmcblk0. CAUTION: Operating on the wrong device can cause damage to that device.

The micro SD card used can be the original SD card shipped with the device or another one that is at least 16 GB in size.

Insert the updated micro SD card and power on the device.

Turning the Device Off/On

To avoid damaging the file system and causing any corruption, do not turn the device off with the power button without first shutting down the system. Use this command to cleanly and properly shut the system down:

   shutdown ­-h now

Enable Auto Booting

Auto booting of the N310 when power is applied can be configured by enabling the flag on the device's EEPROM with the following command:

   eeprom-set-flags 0x1

Network Connectivity

By default, the N310 USRP will be configured as a DHCP client on the 1 Gigabit Ethernet port. Assuming your network resolves hostnames (depends on your routers / switches), if you connect the device to your network, you should see it appear with the hostname ni-n3xx-<motherboard serial #>.​ You can then access the device over SSH.

If the hostname does not resolve, you can discover the IP address by logging into the device over the serial connection, or checking your network’s DHCP tables.

Once you have logged in to the device, you can reconfigure the network settings (e.g., you could configure it for a static IP address, if you wish).

Logging In

When you first log in to the device, the user is ‘root’ and the password is empty (no password).

Example Programs

The UHD driver includes several example programs, which may serve as test programs or the basis for your application program. These example programs are already installed on the N300/N310 USRP, and the source code can be obtained from the UHD repository on GitHub at: https://github.com/EttusResearch/uhd/tree/master/host/examples

Test and Verify the Operation of the USRP

You can quickly verify the operation of your USRP N300/N310 by running the rx_ascii_art_dft UHD example program. The rx_ascii_art_dft utility is a simple console ­based, real­time FFT display tool. It is not graphical in nature, so it can be easily run over an SSH connection within a terminal window, and does not need any graphical capability, such as X Windows, to be installed. It can also be run over a serial console connection, although this is not recommended, as the formatting may not render correctly.

You can run a simple test of the N300/N310 USRP by connecting an antenna and observing the spectrum of a commercial FM radio station in real­time. Please follow the steps listed below.

1. Attach an antenna to the RX2­ antenna port of the N310.

2. Log into the N310 from an external host computer over Ethernet using an SSH client.

3. At a terminal prompt running on the N310, run:

   /usr/lib/uhd/examples/rx_ascii_art_dft ­­--freq 88.1e6 ­­--rate 400e3 ­­--gain 30 ­­--ref­-lvl ­-30

4. Modify the command­line argument freq ​above to specify a tuning frequency for a strong local FM radio station.

5. You should see a real­time FFT display of 400 KHz of spectrum, centered at the specified tuning frequency.

6. Type "Q" or Ctrl­-C to stop the program and to return to the Linux command line.

7. You can adjust the size of your terminal window and then re­run the command to enlarge or shrink the FFT display.

8. You can run with the "​­­help"​option to see a description of all available command­line options.

Additional information is available at the Verifying the Operation of the USRP Using UHD and GNU Radio Application Note.

Technical Support and Community Knowledge Base

Technical support for USRP hardware is available through email only. If the product arrived in a non­functional state or you require technical assistance, please contact support@ettus.com. Please allow 24 to 48 hours for response by email, depending on holidays and weekends, although we are often able to reply more quickly than that.

We also recommend that you subscribe to the community mailing lists. The mailing lists have a responsive and knowledgeable community of hundreds of developers and technical users who are located around the world. When you join the community, you will be connected to this group of people who can help you learn about SDR and respond to your technical and specific questions. Often your question can be answered quickly on the mailing lists. Each mailing list also provides an archive of all past conversations and discussions going back many years. Your question or problem may have already been addressed before, and a relevant or helpful solution may already exist in the archive.

Discussions involving the USRP hardware and the UHD software itself are best addressed through the u​srp­-users ​mailing list at http://usrp-users.ettus.com.

Discussions involving the use of GNU Radio with USRP hardware and UHD software are best addressed through the d​iscuss­-gnuradio​ mailing list at https://lists.gnu.org/mailman/listinfo/discuss­gnuradio​.

Discussions involving the use of OpenBTS® with USRP hardware and UHD software are best addressed through the o​penbts­-discuss​ mailing list at https://lists.sourceforge.net/lists/listinfo/openbts­discuss​.​

The support page on our website is located at https://www.ettus.com/support​. The Knowledge Base is located at ​https://kb.ettus.com​.

Legal Considerations

Every country has laws governing the transmission and reception of radio signals. Users are solely responsible for insuring they use their USRP system in compliance with all applicable laws and regulations. Before attempting to transmit and/or receive on any frequency, we recommend that you determine what licenses may be required and what restrictions may apply.

• NOTE: This USRP product is a piece of test equipment.

Sales and Ordering Support

If you have any non­-technical questions related to your order, then please contact us by email at orders@ettus.com​, or by phone at +1­408­610­6399 (Monday-Friday, 8 AM - 5 PM, Pacific Time). Please be sure to include your order number and the serial number of your USRP.

Terms and Conditions of Sale

Terms and conditions of sale can be accessed online at the following link: http://www.ettus.com/legal/terms-and-conditions-of-sale