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Common Problems and Fixes

Resolve issues encountered during installation or while using the I/O mode features of the support package.

Radio hardware is busy

Problem

MATLAB® returns this warning message from a call to the info method:

 info(dev)
## Establishing connection to hardware. This process can take several 
## seconds. 

Warning: The device with IPAddress 192.168.3.2 is busy. The 
device is already owned by a block, block dialog, or 
System object. Stop the simulation, close the opened dialog, 
or call the release methods of the System Object to allow 
a new owner to be assigned.

This message means that the radio hardware is in use by another MATLAB or Simulink® entity. The radio hardware can become busy when any of the following conditions occur:

  • A Simulink simulation is in progress.

  • A receiver or transmitter block mask is open.

  • A locked receiver or transmitter System object™ is present.

Possible Solution

Release the radio hardware by stopping the simulation, closing the block mask, or calling the release method of the System object.

No data from hardware

Problem

After streaming starts, you do not receive data from the radio hardware.

Possible Solutions

Reestablish Connection.  If you do not have a connection, it is possible that a bad network interface card (NIC), a bad cable, or a loss of power is causing the problem. To reestablish connectivity:

  • Check the cables and power.

  • Follow steps in Select Network Configuration to make sure that you have a basic connection.

  • If you cannot establish communication with the host, check your radio hardware for faulty connections or defects.

Synchronize Software with Radio Hardware

  • For a radio object: Use the info function.

  • For a receiver block: Open the block mask and click Info.

  • For a receiver System object: Use the info function.

Refresh Address Resolution Protocol (ARP) Cache.  You can get this message when the IP address or MAC address binding is refreshed, interfering with the transmission of data from the radio hardware to the host. To avoid the refresh issue, set a static entry in the ARP cache, that is, the table that holds the address bindings. To find the IP address and MAC address, in the block mask of the receiver, examine the hardware information section.

In the following example, the radio hardware is configured with the default IP address 192.168.3.2, and the MAC address is 00-0A-35-02-21-8A.

For Windows®, with system administrator privileges enabled, execute the following in a command shell:

cmd> arp -s 192.168.3.2 00-0A-35-02-21-8A

To confirm that you got the expected outcome, examine the table and verify that the output shows a static entry type:

  cmd> arp -a 192.168.3.2

Interface: 192.168.2.8 --- 0x16
Internet Address      Physical Address      Type
192.168.3.2           00-0a-35-02-21-8a     static

For Linux®, with root or sudo privilege enabled, execute the following in a command shell (note that the MAC address delimiter is ":" instead of "-"):

sh> sudo /usr/sbin/arp -s 192.168.3.2 00:0A:35:02:21:8A

To confirm that you got the expected outcome, examine the table and verify that the output shows a static entry type, as noted by the PERM string.

sh> sudo /usr/sbin/arp -a 192.168.3.2
       
? (192.168.3.2) at 00:0a:35:02:21:8a [ether] PERM on eth3

info function fails

Problem

The radio hardware is not communicating with the host computer. You might get an error similar to the following:

info(dev)
## Establishing connection to hardware. This process can take 
## several seconds.

Warning: Failed to create context for uri: ip:192.168.3.2
The address is not available or the last connection was not 
cleared properly. Make sure the device is connected. If the 
issue persists, click here, and try again.

Possible Solutions

Try these connection checks to see if you can identify where the communication problem is occurring.

Check Host-Hardware Ethernet Connection

  • Check that the radio hardware power is turned on.

  • Check that one end of the Ethernet cable is plugged into the host computer, and that the other end of the cable is plugged into the radio hardware.

  • Check that the Ethernet LEDs are on.

    • If the Ethernet LEDs at one or both ends are not on, check the cable connections at both ends.

    • If the lights still do not come on, try a different Ethernet cable.

  • If you have multiple Ethernet ports on your host computer, check that the radio hardware is connected to the Ethernet port you want.

  • Check that the TCP/IPv4 properties of the host Ethernet connection are as shown in Select Network Configuration.

  • Check that the subnet value of the host and the radio hardware are the same.

  • Repeat the configuration steps.

Check Connection Between Radio Hardware and Operating System.  Check the connection using the ping command and the IP address of the radio hardware.

  1. Open a command window (on Windows) or a shell (on Linux).

  2. Try to contact the radio hardware using the ping command and the IP address of the radio hardware:

    %ping ipaddress

    ipaddress is the IP address of the radio hardware, for example, '192.168.3.2'.

    Note

    Use the IP address of the radio hardware, not the host IP address.

If you get a response to the ping command, then your connection is successful.

If you get the message Request timed out, the network connection setup is incorrect. See Select Network Configuration.

Overruns or underruns

Problem

The model is not running in real time.

Possible Solutions

The device on the specified address is not a known SDR device

Problem

A call to a function that specifies a device address returns an error that the device is not known, it cannot communicate to the radio hardware, or that it failed to find the device.

Possible Solution

  • Check that the radio hardware power is turned on.

  • Check that one end of the Ethernet cable is plugged into the host computer, and that the other end of the cable is plugged into the radio hardware.

  • Check that the Ethernet LEDs are on. If the Ethernet LEDs at one or both ends are not on, check the cable connections at both ends. If the lights still do not come on, try a different Ethernet cable.

  • If you have multiple Ethernet ports on your host computer, check that the radio hardware is connected to the Ethernet port you want

  • Check that the TCP/IPv4 properties of the host Ethernet connection are as shown in Select Network Configuration.

  • Check that the subnet value of the host and the radio hardware are the same.

  • Check that the correct SD card image is inserted in the reader of the hardware.

  • Repeat the hardware configuration steps.

USB-to-Ethernet adapter not recognized

Problem

During the hardware setup process, in the network connection configuration step, you don’t see the USB-to-Ethernet adapter listed in the connection list.

Possible Solution

  • Make sure that Windows has installed it correctly. If you have any difficulty, go to Windows Device Manager > Network adapters. Make sure your dongle is in the list of installed and available devices. If it is not, contact the dongle manufacturer or use the OS to update the drivers.

  • If the dongle is in the Device Manager list, go back to the network connection configuration step and refresh the list. If the adapter still does not show, follow the manual steps to configure the network connection: Select Network Configuration. Then you can return to the hardware setup process and continue.

Host blocking or antivirus software is interfering with the host-hardware communication

Problem

Host blocking or antivirus software is interfering with the host computer’s ability to communicate with the radio.

Possible Solution

  • Turn off the host blocking or network manager utility. Refer to the manufacturer instructions.

  • Turn off antivirus software in Windows, go to Control Panel > Network and Internet > Network Connections. Bring up the properties window for the desired network connection and clear all check boxes apart from Internet Protocol Version 4 (TCP/IPv4).

SD card image fails to download

Problem

When using downloadImage to download the SD card image for a development board, the following error message appears:

### downloadImage failed ...Error attempting to connect to address '192.168.3.2'. 

Cannot connect to the hardware. Following error was returned while attempting to connect: 
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 
@    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @ 
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY! 
Someone could be eavesdropping on you right now (man-in-the-middle attack)! 
It is also possible that a host key has just been changed. 
The fingerprint for the ECDSA key sent by the remote host is 
e1:03:3c:eb:e1:cd:76:52:54:20:af:e0:f1:ed:82:66. 
Please contact your system administrator. 
Add correct host key in /home/user/.ssh/known_hosts to get rid of this message. 
Offending ECDSA key in /home/user/.ssh/known_hosts:381 
Password authentication is disabled to avoid man-in-the-middle attacks. 
Keyboard-interactive authentication is disabled to avoid man-in-the-middle attacks. 
Permission denied (publickey,password,keyboard-interactive).
This issue occurs when the development board uses a SSH key that differs from the key used in the previous connection. These keys are generated on first boot of a new SD card image.

Possible Solution

Remove all SSH host keys belonging to the IP address assigned to the development board. For example:

% ssh-keygen -R 192.168.3.2

Note

Run this command in a terminal and not in a MATLAB console.

ZedBoard overheats

Problem

During SDR processing on a ZedBoard™, the Zynq® processor overheats and stops working.

Possible Solution

ZedBoard Rev B and earlier revisions must have a heat sink attached. (Rev C and later revisions have the heat sink attached already.) If your board has an FMC radio attached but no heat sink, you likely encounter this problem.

RF card falls off development board

Problem

The FMCOMMS RF card tends to fall out of the slot on the Zynq development board, especially when you use a heavy antenna.

Possible Solution

Use the standoffs that come with the SDR development kit.

Clock compatibility check fail

Problem

When you attempt to establish communication between a radio hardware and a System object or block, you get the following error message:

Tx/Rx baseband sample rates do not match.

It is likely that you are trying to send and receive radio signals at different baseband sample rates while using a single device.

Possible Solution

Make sure that the transmitter and the receiver have the same baseband sample rate. See Transmit and Receive On Single Device for more details.

Data reception hangs

Problem

When trying to receive data from the radio hardware, MATLAB or Simulink does not respond.

Possible Solution

When the data timeout property or parameter is set to the default value Inf, MATLAB or Simulink indefinitely waits for data. If you have a custom bitstream loaded onto the board, it is possible that the radio hardware does not return any samples.

  • To release the lock, power cycle the board.

  • Reload the default bitstream:

    dev = sdrdev('AD936x'); 
downloadImage(dev,'BoardName',DeviceName);

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