Required Hardware

The sections below describe the hardware and accessories required to use the Mango 802.11 MAC/PHY Design on the USRP E320 hardware.

E320 Node

The E320 hardware is available in two versions:

The Mango 802.11 design has only been tested on the E320 Standard (full enclosure).

We expect the design would work normally on the bare-board E320, but may require external cooling without the heat sinking provided by the metal enclosure.

Accessing the microSD card

Using the Mango 802.11 design on the USRP E320 requires swapping the microSD card inside the enclosure. The E320 back panel cover must be removed to access the microSD card.The panel is secured by 4 T15 screws. The E320 kit typically includes a T15 wrench.

To swap microSD cards:

  1. Disconnect all cables from the E320 node
  2. Remove and save the four T15 screws on the back panel
  3. Carefully remove and save the back panel cover
  4. The microSD card is on the bottom side of the E320 board - press the card in to release it
  5. Insert the new microSD card containing the 802.11 design boot files (see Getting Started)
  6. Replace the back panel cover and screws

Required Accessories

MicroSD Card and Reader

The E320 boots from a microSD card. The SD card supplies the firmware binary for the Embedded Controller, the configuration bitstream for the Zynq PL, and application binaries for the Zynq CPUs. The E320 ships with an SD card initialized at the factory for use with the standard USRP SDR software suite.

We strongly recommend you save the factory microSD card and use a new card with the 802.11 design!

The Mango 802.11 design for the USRP E320 requires a FAT-formatted microSD card with minimum capacity of 128MB; larger microSD cards work fine.

A microSD card reader is also required to read/write files on the card from a PC.

Micro USB Cable

A single micro USB cable is required to connect the E320 to a host PC for debug and development. The E320 kit typically includes a good micro USB cable.

The E320 implements an on-board USB hub with three peripherals:

  • Digilent USB-JTAG circuit
  • CP2105 USB-UART
  • SMT32 EC microcontroller

The Xilinx Vivado and SDK tools will detect and use the Digilent USB-JTAG circuit automatically.

The USB-UART interfaces are very useful during software development.

The SMT32 EC USB connection is not used in the 802.11 design.

USB Flash Drive

By default the 802.11 design boots the E320 from the microSD card. However iterating on the design via the microSD card is inconvenent; the E320 back panel cover must be removed to access the SD card slot, and inserting/removing the SD card is tedious.

For easier iteration the 802.11 design also supports loading the FPGA bitstream from a USB drive attached to the USB port on the back of the E320. The USB port can be accessed when the E320 back panel cover is installed.

The Mango 802.11 design for the USRP E320 requires a FAT-formatted USB drive with minimum capacity of 128MB; larger drives work fine.

The USB flash interface is implemented by the u-boot bootloader. There are reports of issues using u-boot with older USB drives. We have tested a number of modern USB 2.0 flash drives successfully. We use and recommend the SanDisk 16GB Cruzer Fit (SDCZ33-016G-G35) drive (Amazon link).

RF Accessories

The E320 routes RF connections to front-panel SMA jacks. You must supply whatever RF accessories are required for your application. For example to test multiple nodes over a wired connection, you will need RF cables with SMA plugs, attenuators, splitters/combiners, etc.

Refer to the NI E320 Documentation for details on RF connections, such as maximum Tx/Rx power.

We recommend connecting 50-ohm SMA terminators to all unused front-panel SMA jacks before running the 802.11 design. There are many terminator options; we use the Amphenol 132360.

Ethernet Cable & Network

The 802.11 MAC/PHY Design uses the E320 Ethernet interface for wired-wireless bridging (i.e. connecting wireless clients to the internet) and for experimental controal via wlan_exp.

To serve wireless internet access the E320 node must be connected to an Ethernet network with a DHCP server, router, and active internet connection. The 802.11 AP application will bridge wireless clients to this wired network, enabling wireless clients to receive DHCP address assignments and access the internet.

An internet connection is not required to use the wlan_exp framework to control the 802.11 design running on the E320.