Finite State Machine Control Research Articles

Concurrent error detection using monitoring machines

In circuits implementing system level functions, the correctness of the overall operation is critically dependent on the correctness of the control part. Therefore, concurrent error detection techniques for controllers implemented in integrated circuits have previously received wide attention. This paper presents a new technique for concurrent error detection in finite state machine (FSM) controllers. It is based on the use of monitoring machines. In a monitored FSM controller, an auxiliary monitoring machine operates in lock-step with the main FSM, such that any fault in either of the two machines is immediately detected. It is shown how the monitoring machine provides a uniform mechanism for the detection of stuck-at faults as well as delay faults. Besides being less costly than the main machine, it is also not identical to it. These features yield designs which compare very favourably with previous implementations. Not only is the fault coverage higher, also the hardware cost of the monitored sequential circuit is significantly lower.

Steady-state optimal control of finite-state machines

The basic problem considered here is the optimal control of finite-state machines operating over an infinite time interval. This is essentially a deterministic version of the theories of Howard [4] and Eaton and Zadah [5] on the control of Markov [email protected]? The deterministic theory presents certain special problems, not found in the stochastic theory. This is especially so for finite state machines whose closed-loop dynamics always include periodic motions, cyclic machines. This class of dynamical system is of interest in Economic and Biological systems where the system behavior is often inherently periodic. Necessary and sufficient conditions are given for optimal control. However, the necessity condition, given in Theorem 4, requires more restrictive assumptions than the sufficiency condition, given in Theorem 2. Also, while both cyclic and absorbing-state machines, with all transient states and one absorbing state, are considered, the major emphasis is on cyclic machines.