| 摘要 |
PURPOSE:To quickly detect the working abnormality of a data processor or the system working fault and at the same time to improve the system working efficiency by providing a fault occurrence monitoring circuit which contains the upper and lower limit value setting registers, an arithmetic circuit, etc. CONSTITUTION:The upper and lower limit addresses are previously set at an upper limit value setting register 21 and a lower limit value setting register 20 of a fault occurrence monitoring circuit 17 provided on a microprocessor in a prescribed range that can set by a program counter. Then it is decided during the executing control of an instruction whether or not the value of the counter 11 is kept within a range between the upper and lower limit addresses which are set by both registers 20 and 21 via arithmetic circuits 22 and 23 and a logic gate 24. If not, the level of the output signal Z of the gate 24 is set at 0 and the signal Zi is outputted to an interruption circuit via a control circuit 25. Then the working of the microprocessor is branched out to an exceptional process. Thus it is possible to quickly detect the working abnormality of a data processor itself or the system working fault and also to improve the system working efficiency. |
