Patent ID: 7181559

Claim:
An interrupt handling apparatus for a system in which a plurality of interrupt sources share a level sensitive interrupt, the interrupt handing apparatus comprising: an interrupt input unit configured to receive level sensitive interrupt requests and generate request occurrence signals therefrom, each request occurrence signal indicating that a level sensitive interrupt request has been received; an edge detection unit connected to said interrupt input unit and configured to receive said request occurrence signals and generate start signals for edge triggered interrupt messages on the basis of the received request occurrence signals; and an interrupt termination detection unit configured to receive termination signals each indicating that an interrupt routine relating to a previous edge triggered interrupt message has terminated, wherein, in response to receiving a termination signal relating to a first edge triggered interrupt message generated on the basis of a request occurrence signal associated with a first level sensitive interrupt request received from one of the plurality of interrupt sources, said interrupt termination detection unit is configured to control said interrupt input unit to output a request occurrence signal for generating a second edge triggered interrupt message if a second level sensitive interrupt request previously received from another one of the plurality of interrupt sources is still active.