Systems simulation of an advanced avionics COMSEC unit

The authors discuss JAID (JIAWG/AACU Interoperability Demonstration), the simulation of the AACU (Advanced Avionics COMSEC Unit) in an integrated avionics system. The AACU is the next generation of avionics COMSEC (communications security) devices. The simulation model of the AACU involves doing a gate-level model of the AACU bus interface hardware and a behavioral model of the functionality of the rest of the AACU. The AACU functionality demonstrated by the behavioral model involves emulating custom LSI and several microprocessors which perform the black box COMSEC functionality of the AACU. The behavioral model emulates the correct timing, state transition, and COMSEC functionality of the AACU. Issues involved in writing a behavioral model for a mixed-mode (behavioral and gate-level) simulation are emphasized.<>