Abstract: A method is described for identifying an inaccurate model of a hardware circuit. The method includes the steps of simulating the model of the circuit by applying a plurality of signals, said plurality of signals having at least one abstract data type level to provide a set of expected results, replacing the at least one abstract data type level with two or more levels having different values to thereby provide and expanded set of signals to apply to said model, resimulating the model with said expanded set and comparing the two sets of results and providing an output signal indicating if the model is inaccurate if the results contradict.

Abstract: A method is described for reducing delays in an analogue simulation model of a hardware circuit. The method includes the steps of stimulating via an input an output of said analog model, said output and said input having a relatively high resistance therebetween and applying a pulse to a relatively low resistance, whereby when said pulse is applied to the relatively low resistance, the input is connected to said output via the relatively low resistance so that the time constant of the circuit is reduced.

Abstract: A method is described for distinguishing between an input or output signal on a bi-directional pin of a model of a hardware circuit. The method includes the steps of for a bi-directional pin of said model applying signals to said pin at a reduced drive strength such that a driven signal on said pin will be superimposed over the applied signal, and comparing the drive strength on the bi-directional pin and responsive to said comparison determining whether the bi-directional pin is an input or output.

Abstract: A method is described for converting a data set for use with a digital model of a hardware cell into an expanded data set for use with an analog model of the hardware cell. The method including the steps of determining the signal required to drive one or more pins of said analog model by analyzing whether the signals used in said digital model are in a first category or a second category, said first category containing relatively simple signals and said second category containing relatively complex signals, and providing the signal required for the one or more pins in the analog model in dependence on said analysis.

Abstract: A method is described for verifying the output from an analogue simulation model of a hardware circuit. The method includes the steps of stimulating the analog model by applying a preselected voltage to an input pin of the analog model, driving one or more selected output pins of the analog model with a test voltage having a selected drive strength different from an expected output drive strength, measuring the output voltage of each output pin, comparing the measured output voltage and the expected output voltage and responsive to said comparison, providing a verifying output if the measured and expected voltages are not in contradiction.

Abstract: A method and system for identifying an inaccurate model of a hardware circuit includes the steps of simulating a digital model and an analogue model of the circuit to provide first and second sets of simulation results respectively. For each result in the first and second sets of simulation an integer value is determined which represents that result. The integer values are stored in first and second sets of comparison results respectively and the sets of comparison results are compared. An output signal indicating that at least one of the models is inaccurate is produced if the comparison results contradict.