Mixed-mode-simulator interface

Claim 2

A mixed-mode-simulator interface for synchronizing, at non-regular intervals, a system simulator which includes an analog simulator, which analyzes continuous-function elements and events at non-equal, error-determined intervals in an analog realm, and which has a predetermined threshold-crossing value therein, and an event-driven simulator, which analyzes elements and events at non-equal, event-driven intervals in an event-driven realm, wherein both simulators are performing a simulation on a single, mixed-mode system, comprising: analog-time-advance means for advancing analog simulation time by a predetermined time amount; integration means for predicting analog values; analog-error-analysis means for determining an acceptable analog error and for selecting said predetermined time amount; an analog-function-threshold-crossing sensor for detecting, from the threshold-crossing value, a threshold crossing of a continuous function, and a crossing time therefore; an event queue for receiving said crossing time and event times and values from the event-driven simulator, and for determining a next-event time; evaluation means for evaluating only those event-driven elements whose value has changed since the last event; and synchronizer means for determining continuous function values at a future time which is prior to the end of said predetermined time amount.

Claim 3

The interface of claim 1 wherein said synchronizer means includes a polynomial-interpolation-rollback controller for examining continuous function elements at a future time prior to the end of said predetermined time amount.

Claim 4

The interface of claim 1 which further includes initialization means, including an event queue, which is operable to receive initial, preset external and internal values, and wherein all continuous values are initially set to zero; a counter i, which is initially set to zero; means for advancing said counter; continuous function evaluation means for evaluating continuous elements and events during the advancing; event-driven evaluation means for evaluating event-driven elements and events during the advancing; and comparison means in each of said continuous function evaluation means and said event-driven evaluation means for detecting changes in one realm as a result of changes in the other realm.

Claim 5

A mixed-mode-simulator interface for synchronizing, at non-regular intervals, a system simulator which includes an analog simulator, which analyzes continuous-function elements and events at non-equal, error-determined intervals in an analog realm, and which has a predetermined threshold-crossing value therein, and an event-driven simulator, which analyzes elements and events at non-equal, event-driven intervals in an event-driven realm, wherein both simulators are performing a simulation on a single, mixed-mode system, comprising: a time-advance synchronizer located between the analog and event-driven simulators which includes means for advancing the analog simulator by a time interval H of varying length; means for advancing the event-driven simulator by a varying-length time amount; integration means for determining continuous-function values during time interval h; algebraic means for determining event-driven values during the time amount; continuous-function examination means for determining events in the analog realm; and rollback means for evaluating interaction between the analog and digital realms and evaluating the continuous-function values at a time intermediate the beginning time B and a time B+h.

Claim 6

A mixed-mode-simulator interface for synchronizing, at non-regular intervals, a system simulator which includes an analog simulator, which analyzes continuous-function elements and events at non-equal, error-determined intervals in an analog realm, and which has a predetermined threshold-crossing value therein, and an event-driven simulator, which analyzes elements and events at non-equal, event-driven intervals in an event-driven realm, wherein both simulators are performing a simulation on a single, mixed-mode system, comprising: a time-advance synchronizer located between the analog and event-driven simulators which includes means for advancing the analog simulator by a time interval H of varying length; means for advancing the event-driven simulator by a varying-length time amount; integration means for determining continuous-function values during time interval h; algebraic means for determining event-driven values during the time amount; continuous-function examination means for determining events in the analog realm; and rollback means for evaluating interaction between the analog and digital realms and evaluating the continuous-function values at a time intermediate the beginning time B and a time B+h.

Claim 7

The interface of claim 4 wherein said rollback means includes a polynomial-interpolation-rollback controller for moving backwards in time along a continuous-function in the analog realm.

Claim 8

The interface of claim 4 which includes a continuous-function-threshold-crossing sensor for detecting, from the threshold-crossing value and said integration means, a threshold crossing, and a crossing time therefore.

Claim 9

The interface of claim 4 which further includes initialization means, including an event queue, which is operable to receive initial, preset external and internal values, and wherein all continuous values are initially set to zero; a counter i, which is initially set to zero; means for advancing said counter; continuous function evaluation means for evaluating continuous elements and events during the advancing; event-driven evaluation means for evaluating event-driven elements and events during the advancing; and comparison means in each of said continuous function evaluation means and said event-driven evaluation means for detecting changes in one realm as a result of changes in the other realm.

Claim 10

A mixed-mode-simulator interface for synchronizing, at non-regular intervals, a system simulator which includes an analog simulator, which analyzes continuous-function elements and events at non-equal, error-determined intervals in an analog realm having continuous functions, and which has a predetermined threshold-crossing value therein, and an event-driven simulator, which analyzes elements and events at non-equal, event-driven intervals in an event-driven realm, wherein both simulators are performing a simulation on a single, mixed-mode system, comprising: initialization means, including an event queue, which is operable to receive initial, preset external and internal values, and wherein all continuous values are initially set to zero; a counter i, which is initially set to zero; means for advancing said counter; continuous function evaluation means for evaluating continuous elements and events during the advancing; event-driven evaluation means for evaluating event-driven elements and events during the advancing; and comparison means in each of said continuous function evaluation means and said event-driven evaluation means for detecting changes in one realm as a result of changes in the other realm; transient analysis means, including analog-time-advance means for advancing analog simulation time by a predetermined time amount; integration means for predicting analog values; analog-error-analysis means for determining an acceptable analog error and for selecting said predetermined time amount; an analog-function-threshold-crossing sensor for detecting, from the threshold-crossing value, a threshold crossing, and a crossing time therefore; an event queue for receiving said crossing time and event times and values from the event-driven simulator, and for determining a next-event time; evaluation means for evaluating only those event-driven elements whose value has changed since the last event; and synchronizer means including a polynominal-interpolation-rollback controller for examining continuous elements at a future time prior to the end of said predetermined time amount.

Claim 11

A mixed-mode-simulator interface for synchronizing, at non-regular intervals, a system simulator which includes an analog simulator, which analyzes continuous-function elements and events at non-equal, error-determined intervals in an analog realm having continuous functions, and which has a predetermined threshold-crossing value therein, and an event-driven simulator, which analyzes elements and events at non-equal, event-driven intervals in an event-driven realm, wherein both simulators are performing a simulation on a single, mixed-mode system, comprising: initialization means, including an event queue, which is operable to receive initial, preset external and internal values, and wherein all continuous values are initially set to zero; a counter i, which is initially set to zero; means for advancing said counter; continuous function evaluation means for evaluating continuous elements and events during the advancing; event-driven evaluation means for evaluating event-driven elements and events during the advancing; and comparison means in each of said continuous function evaluation means and said event-driven evaluation means for detecting changes in one realm as a result of changes in the other realm; transient analysis means, including analog-time-advance means for advancing analog simulation time by a predetermined time amount; integration means for predicting analog values; analog-error-analysis means for determining an acceptable analog error and for selecting said predetermined time amount; an analog-function-threshold-crossing sensor for detecting, from the threshold-crossing value, a threshold crossing, and a crossing time therefore; an event queue for receiving said crossing time and event times and values from the event-driven simulator, and for determining a next-event time; evaluation means for evaluating only those event-driven elements whose value has changed since the last event; and synchronizer means including a polynominal-interpolation-rollback controller for examining continuous elements at a future time prior to the end of said predetermined time amount.

Claim 14

The method of claim 9 which includes, prior to said determining of a threshold-crossing value, initializing the simulator, said initializing including the steps of: setting initial event-driven external and internal values in an event queue; setting an event counter i=0; setting all continuous values to zero; propagating events, in the event-driven realm, using event-driven simulation; integrate continuous functions from i-1 to i; detect threshold crossings between i-1 and i, and enter crossing times into event queue; further propagating events in the event driven realm; and analyzing continuous function for changes as a result of changes in the event-driven realm.