GENERAL I/O DEVICE CAPABLE OF PROCESSING EDGE INTERRUPT

摘要

PURPOSE: A general I/O device(20) capable of processing an edge interrupt is provided to automatically disable an interrupt signal inputted to a CPU(30) in such a manner that the general I/O device(20) detects a condition for generating an edge interrupt and the CPU(30) processes all interrupts. CONSTITUTION: A general I/O device(20) capable of processing an edge interrupt includes the following units. A register(21) temporally processes an intermediate result during the processing of a CPU(30). An interface unit(22) interfaces with the CPU(30). A interrupt control unit(23) judges if an inputted external interrupt signal is an edge interrupt signal or not, and generates the corresponding internal interrupt. A restoration signal generation unit(24) generates a signal for disabling an interrupt when the CPU(30) finishes an interrupt processing. A multiplexor(25) multiplexes with an external pad. The restoration signal generation unit(24) includes a NAND gate for NAND-processing an internal interrupt signal and a cancellation signal.