Patent ID: 8127183
Filing Date: 2012-02-28
Classification: G06F

Abstract:
1. A microcomputer system for simultaneously performing a plurality of tasks by time sharing, one of the plurality of tasks being defined as a most important task having a higher priority than any other task, the microcomputer system comprising: a central processing unit including a signal output section for outputting a task information signal indicative of whether the central processing unit performs the most important task at a present time, the task information signal having a first state if the central processing unit performs the most important task at the present time and having a second state if the central processing unit doesn't perform the most important task at the present time; a memory having a program area for storing a program for the most important task, the program area being defined by a program start address and a program end address; and a runaway detector including a program start address register for storing the program start address, a program end address register for storing the program end address, and a program area checker for determining whether an execution address, where an instruction performed by the central processing unit at the present time is located, is within the program area by comparing the execution address with each of the program start address and the program end address, the runaway detector receiving the task information signal from the central processing unit and detecting a task runaway in the event of conflict between a state of the task information signal and a result of a determination of the program area checker, wherein the memory further has a data area for storing data for the most important task, the data area being defined by a data start address and a data end address, the runaway detector further includes a data start address register for storing the data start address, a data end address register for storing the data end address, and a data area checker for determining whether the execution address is within the data area by comparing the execution address with each of the data start address and the data end address, and the runaway detector detects the task runaway in the event of conflict between the state of the task information signal and a result of a determination of the data area checker.