Problem:

(a) Use a simple example to explain what is meant by a finite state machine.

(b) Describe the time limit problem in an interrupt-driven system.

(c) A certain machine control has three push-button switches:

forward, stop and reverse. If the machine is moving forward it must be stopped before it can run in reverse. Likewise if it is running in reverse, it must be stopped before moving forward.

(i) Draw the state transition diagram

(ii) Draw a state table

(iii) Write the 8051 code to implement such a controller

(d) A system is planned to have four interrupts with the following specifications.

Calculate whether or not the system will be interrupt-bound.