xcell takes a cell library in the ACT format as well as a top-level module that instantiates all the cells to be characterized as input.
It creates a large number of scenarios that are simulated using an external SPICE simulator, and the results of SPICE simulation are analyzed.
These results are used to create a Synopsys-format .lib file suitable for use by timing analysis and power analysis tools.
To run, use:
xcell [-Ttech] top.act out
This will create out.lib. xcell also requires:
- A configuration file
xcell.confin the current directory that is used to specify the details of the characterization process. - A spice file
stdspice.spicontaining the spice models for the devices.
An example configuration is provided in the example/ directory.
The input actfile must have a process called characterize with no parameters, which is instantiated at the end of the file. The process must have a list of cells named g1, g2 ... gN in order. xcell starts looking for these cells sequentially, starting from g1. If any of them are not found, it exits. See char.act in the example directory for the exact input format that is required.
This program is for use with the ACT toolkit.
- Please install the ACT toolkit first; installation instructions are here.
- Build this program using the standard ACT tool install instructions here.
xcell invokes an external SPICE simulator. Currently it supports Xyce as well as hspice as external SPICE simulators. The simulator to be used is specified in the xcell.conf file. The simulator binary must be in the current path so that xcell can invoke it successfully.