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OpenAccess Support

This interface is presently not available under Microsoft Windows.

OpenAccess is an open-source database for CAD/EDA data. It is used by Cadence Virtuoso 6.x, and by many other tools. It provides a commonality among tools from different vendors, and is intended to facilitate seamless integration of tools from different vendors into a process flow. OpenAccess is distributed by Si2 ( Source code and binary distributions are available for a number of operating systems, to registered users and coalition members.

Xic can connect to an OpenAccess (OA) database through a plug-in, which is supplied with all Xic releases for other than Microsoft Windows, on which there is no OA support. Since there is no default location for OA, the user must set the XIC_LIBRARY_PATH or the LD_LIBRARY_PATH variable to include the library location in the search path during program loading. This is most conveniently done in the user's shell startup script.

Presently, the plug-in is compiled with the OpenAccess releases below. The plug-in can work with libraries from newer OpenAccess releases, but not with libraries from an older release.

Distribution OpenAccess Release
LinuxRHEL5 (32 and 64 bit) 22.04.054
all others 22.04.064

These are known to be compatible will OpenAccess from Ciranova PyCell Studio release 4.7.1 and later, and Cadence Virtuoso 6.1.4 and later. This includes Virtuoso 6.1.7 which jumps to OpenAccess API level 5. The existing plugin can handle API levels 4 and 5.

There are at least three ways to obtain OpenAccess.

  1. From a Cadence Virtuoso installation on the same computer.
  2. From a Ciranova (now Synopsys) PyCell Studio portable-pcell installation on the same computer.
  3. From an OpenAccess distribution from the Si2 organization.

The OpenAccess plug-in is provided with OS X releases, though (regrettably) Ciranova and Cadence do not support the platform. Those inclined can get OpenAccess from Si2 and build it on OS X, using patches available from the Whiteley Research web site. Unlike Windows, OS X is inherently a first-class CAD platform, too bad the big guys don't support it. The patch also ports OpenAccess to FreeBSD, and improves support for recent Linux releases.

Probably, the main interest in using OA is for limited compatibility with Cadence Virtuoso. There are two levels here. The first level is compatibility with the OA system. This is basically complete, as any Xic design can be saved to and read from OA without data loss or change. The second level is compatibility with the conventions and methods used in the Virtuoso product, much of which is proprietary or undocumented. This is a much tougher nut to crack. Presently, there is fairly reasonable capability of taking Virtuoso designs into Xic, but the reverse is not true. Presently, physical (layout view) data from Xic can be read by Virtuoso and should appear correct, however there is no netlist information or connection to a schematic. It is as if the layout view was read from a GDSII file. Schematic and schematic symbol views from Xic can not be read as anything but garbage by Virtuoso. There are plans for a data translation stage in the future to possibly adapt Xic schematics to Virtuoso format.

When the OpenAccess plug-in is loaded, there are several changes to Xic.

  1. There is an OpenAccess Libs entry added to the File Menu. Pressing this will bring up the OpenAccess Libraries panel, which provides access to the existing OpenAccess design data.

  2. A number of ``bang'' commands (text-mode commands that start with '!') are made available. These commands are typed into the prompt line to start. Much of the functionality of these commands is also available graphically in the panel.

In addition, the standard commands for reading and writing design data become operable with OpenAccess data. When specifying a cell, one provides two words: the OpenAccess library name and the cell name.

It is not possible to write to an OA library unless the library has been ``branded'' by Xic. By default, libraries created in Xic are writable from Xic, libraries created by other tools are not. The read-only status from Xic of any library can be set from the OpenAccess Libraries panel, or with the !oabrand command.

next up previous contents index
Next: Representing Xic Cells in Up: Xic Configuration and Startup Previous: Plug-Ins   Contents   Index
Stephen R. Whiteley 2021-01-27