In the instructions below, substitute your UW Net ID wherever you see "uwnetid".

Last updated: 5 Apr 2016

• Overview
• Installation on Windows
• Usage from Windows
• Usage from Mac OS/X
• Troubleshooting Problems

Cadence

Cadence is a large collection of programs for circuit design, layout, simulation and preparation for manufacturing. Two of the primary toolsets are:

• Virtuoso

  The Virtuoso family of tools provide schematic editing, layout support, electrical verification, and visualization and analysis of waveforms.

• Spectre

  Spectre is Cadence's SPICE tool for circuit simulation.

Most of the Cadence tools are Linux based and run on a server. Access to this server is via a remote desktop application -- in our case, this is VNC. Once you install the environment, you use a VNC client to connect to the server and open up a remote desktop as another window on your local computer's desktop. Inside the remote desktop, you open up a terminal window and run the appropriate script to run the desired tool.

Installation on Windows

Installing the local application or client involves downloading a .zip file and unzipping it.

1. Download cadman.zip
2. Unzip cadman.zip into the C:\ folder.
3. Look at the contents of the C:\cadman folder.

   You should see one cadman.ini file and several .exe and .cmd files.

   The cadman.ini file is where you can override some defaults; for example, if the server IP address or hostkey changes. You don't normally need to modify this file, although sometime it is useful if the username you logged in as in not the same as your UW NetID. You want to put your UW NetID and/or your password in that file — be very carefukl about saving your password, as it is saved in plain text.

Usage from Windows

Before you can use Cadence tools, you must first connect to the server on which the Cadence design and simulation tools are installed.

Background

PuTTY's plink command is a remote shell command -- basically, it is the command-line version of the putty.exe GUI. plink uses your login account on the remote server to start the remote display mechanism -- the VNC remote display service. Your login account is the same as your UW NetID, and your MyUW password is required. plink is also used to provide an encrypted connection to the server, to protect passwords and your work.

When the VNC server is started, it sets a unique port per user. That port is used by plink to provide the encrypted tunnel, and the VNC viewer command (vncviewer.exe) to connect to the remote display service via the tunnel.

cadman.exe automates all of that for you. It makes sure it can find plink.exe and vncviewer.exe, uses plink to start the VNC remote display service, gets the returned port number, opens up a tunnel using plink (which must remain open), and then starts vncviewer to use the tunnel and connect to the remote display service.

Once the connection is made, an additional password, the VNC password, is also required. The VNC password restricts access to the remote display service to those who know both the port number and the service.

Using Cadence from Windows

To use Cadence tools after installation:

1. Browse to the C:\cadman folder.
2. Run cadman.exe

   By default, cadman.exe uses the value of the USERNAME environment variable to login to the remote server. On a personal computer, this may not be the same as your UW NetID. In that case, you should do one of the following:

   • override the name shown in the window

          If needed, change xxxxxxxx to your UW NetID
          

     Change the textbox value "xxxxxxxx" to your UW NetID.

   • or, modify cadman.ini
     1. close cadman
     2. edit the cadman.ini file, adding your UW NetID after uwnetid=
     3. start cadman.exe
     
     
   • or, run cadman.exe from the command line
     1. open a command shell or prompt

        For Windows 7, go to the Start Menu and enter cmd.

        For Windows 8.1, right-click on the Start Menu and select Command Prompt.

     2. Change folder to C:\cadman

               cd /d c:\cadman
               

     3. Run the script with your UW NetID as an argument.

               cadman uwnetid
               

        where "uwnetid" is your UW NetID.

3. Click on the Connect to Cadence Desktop via VNC Service button

   You may be prompted for your MyUW password -- enter it when requested. It will be remembered until you close cadman.

   A command shell will open, with some information that looks like:

   Connecting to remote system for port...
   
   New 'cn10-vcl8:4 (srondeau)' desktop is cn10-vcl8:4
   
   Starting applications specified in /home/srondeau/.vnc/xstartup
   Log file is /home/srondeau/.vnc/cn10-vcl8:4.log
   
   Port 5904 acquired.
   Starting the ssh tunnel...
   
   Press any key to continue . . .
     

   Press the enter key.

   Then you will see a VNC authentication window from the VNC remote display service, prompting for a password.

4. Enter the VNC password.

   The default VNC password is listed in the command shell window. You should change that password (eventually) by clicking on the Set VNC Service Password button — note that setting the password will shut down the existing VNC remote display service to do change the password.

5. Do your work in Cadence.

   On the remote server, open a terminal window and enter either of these commands:

   1. cad-ncsu

      This starts Cadence's Virtuoso and related tools with the NCSU Cadence Design Kit (CDK) or library.

   2. virtuoso

      This starts Cadence's Virtuoso and related tools with the default library.

   3. spectre

      The spectre script requires at least an input file name as an argument. The input file is a netlist file; e.g.

          spectre sample.netlist
          

      To look at options for the command:

          spectre -help
          

6. When finished and you no longer want the VNC remote display service active, shut it down.

   The remote display service stays up until you explictly shut it down. That is done by clicking on the Kill Cadence Desktop VNC Service button.

Usage from Windows

Before you can use Cadence tools, you must first connect to the server on which the Cadence design and simulation tools are installed.

Background

PuTTY's plink command is a remote shell command -- basically, it is the command-line version of the putty.exe GUI. plink uses your login account on the remote server to start the remote display mechanism -- the VNC remote display service. Your login account is the same as your UW NetID, and your MyUW password is required. plink is also used to provide an encrypted connection to the server, to protect passwords and your work.

When the VNC server is started, it sets a unique port per user. That port is used by plink to provide the encrypted tunnel, and the VNC viewer command (vncviewer.exe) to connect to the remote display service via the tunnel.

cadman.exe automates all of that for you. It makes sure it can find plink.exe and vncviewer.exe, uses plink to start the VNC remote display service, gets the returned port number, opens up a tunnel using plink (which must remain open), and then starts vncviewer to use the tunnel and connect to the remote display service.

Once the connection is made, an additional password, the VNC password, is also required. The VNC password restricts access to the remote display service to those who know both the port number and the service.

Using Cadence from Mac OS/X

To use Cadence tools after installation, you will primarily be using ssh in a terminal window to set up and control the remote display session. You may like these instructions better if you prefer the GUI method.

1. Connect to Cadence Desktop via VNC Service
   1. Open a terminal window
   2. Start the VNC service to get the remote port number.

          ssh uwnetid@cadence.insttech.washington.edu vncstart
          

      For uwnetid, provide your UW Net ID. When prompted for a password, use your MyUW password.

      For example, my UW Net ID is srondeau, so I would run:

          ssh srondeau@cadence.insttech.washington.edu vncstart
          

      and enter my MyUW password when prompted.

      You should see something similar to the output below:

          New 'cn10-vcl8:9 (srondeau)' desktop is cn10-vcl8:9
        
          Starting applications specified in /home/srondeau/.vnc/xstartup
          Log file is /home/srondeau/.vnc/cn10-vcl8:9.log
        
          vncport 5909
          

      My remote port number is 5909, as can be seen from this line above:

          vncport 5909
          

      Remember this to fill in remport in the next step.

   3. Establish an ssh tunnel to protect your VNC session:

          ssh -f uwnetid@cadence.insttech.washington.edu -L 15900:127.0.0.1:remport sleep 60
          

      For remport, provide your VNC port number from vncstart. If you are returning to an already-established VNC session, you can ask what your VNC port is:

          ssh uwnetid@cadence.insttech.washington.edu vncport
          

   4. Display the default VNC password (which will work unless you changed it).

          ssh uwnetid@cadence.insttech.washington.edu vncpw
          

   5. Open a VNC session to the remote computer:

          open vnc://127.0.0.1:15900
          

   6. Enter the VNC password when prompted.

      The default VNC password is listed in the command shell window. You should change that password (eventually) by following the Set VNC Service Password instructions — note that setting the password will shut down the existing VNC remote display service to do change the password.

2. Do your work in Cadence.

   On the remote server, open a terminal window and enter either of these commands:

   1. cad-ncsu

      This starts Cadence's Virtuoso and related tools with the NCSU Cadence Design Kit (CDK) or library.

   2. virtuoso

      This starts Cadence's Virtuoso and related tools with the default library.

   3. spectre

      The spectre script requires at least an input file name as an argument. The input file is a netlist file; e.g.

          spectre sample.netlist
          

      To look at options for the command:

          spectre -help
          

3. When finished and you no longer want the VNC remote display service active, shut it down.

   The remote display service stays up until you explictly shut it down. That is done by following the Kill Cadence Desktop VNC Service instructions.

4. Set VNC Service Password
   1. Open a terminal window
   2. Change the password

          ssh uwnetid@cadence.insttech.washington.edu setvncpw "newpw"
          

      where newpw is the new password you want.

5. Kill Cadence Desktop VNC Service
   1. Open a terminal window
   2. Stop the VNC service

          ssh uwnetid@cadence.insttech.washington.edu vncstop
          

Troubleshooting Problems

1. Access Denied

   There are a few possibilities:

   1. The MyUW password you supplied was not accepted by the remote server.

      You probably entered the wrong password. You may have to close cadman and then start it again to "forget" the wrong password.

   2. USERNAME is not the same as UW NetID

      The default user name is the value of the Windows USERNAME environment variable. The most likely cause of this error is that the USERNAME value is not the same as your UW NetID. Refer to this explanation to determine how to resolve that.

   3. Unknown login account for valid UW NetID

      Another possibility is that a valid UW NetID is used, but there is no login account that matches it on the remote server. In that case, please contact your instructor or lab staff.

2. FATAL ERROR: Network error: Software caused connection abort

   This indicates that your IP address is being blocked by the remote server, probably due to too many failed login attempts. Please contact lab staff via email and provide your IP address. Your IP address can be seen by visiting this web page.

3. Connection Abandoned

   This usually occurs when plink required an answer to a question, but the script failed to answer it. If you try to connect manually:

     plink uwnetid@140.142.71.52
     

   using your UW NetID instead of "uwnetid", you should answer "y" to the question about caching information, then provide your MyUW password when prompted. If you login successfully, simply enter exit to log out. After that, you can use cadman.exe to connect to the server using the remote desktop service.

4. FATAL ERROR: Host key did not appear in manually configured list

   The hardcoded host key provided in cadman.exe and cadman.ini no longer match the host's key. Try downloading and unzipping cadman.zip in case there is an updated version (the version number appears in the window title). If cadman.exe still fails with this message, please contact lab staff.

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