ACSL is widely used for the time-domain simulation of mechanical, aerodynamic, hydraulic and other dynamical systems described by nonlinear ordinary differential equations. Today, many larger systems contain electrical or electronic subsystems with semiconductor devices. For the simulation of such subsystems, specialized software tools are used. One such program is SPICE, a general purpose circuit simulator developed at the University of California at Berkeley which has become a standard in industry, research and education.
The ACSL-SPICE-Interface was developed for the simultaneous simulation of mixed systems containing ACSL-type and SPICE-type subsystems. The interface works within the familiar ACSL environment and is based on an ACSL feature which allows calls to compiled Fortran subroutines from the model code. The SPICE Version 3F5 source code was implemented in such a way that its routines can be called in library form. Additionally, routines were developed which call those parts of SPICE which read in the circuit file, initialize the simulation and perform the numerical integration in the time-domain.
To simulate a mixed system, the user first defines the subsystems to be modeled in ACSL (i.e. mechanical, hydraulical, etc.) and the electrical/electronic subsystems to be modeled in SPICE. After selection of the state variables for data exchange between the ACSL- and SPICE-submodels, the ACSL model file and the SPICE circuit file are written. The interface calls are put into the ACSL model file. After selection of an appropriate integration algorithm and step size, the simulation may be started. Results can be viewed and printed within the ACSL runtime environment as usual.
The ACSL-SPICE-Interface combines the time-proven tools ACSL and SPICE for a straight-forward and effcient simulation of complex mixed systems which contain electrical or electronic subsystems.