Interrupt controller that reduces the number of scans needed to identify priority

摘要

An interrupt controller is so configured that if the priority level is divided into 2n or less levels, the priority levels are scanned in the order of 2n->2n-1->. . . 20, and the priority levels having the same order of priority are scanned on the basis of the default values at only one timing. Therefore, even if interrupt requests having the same priority levels compete with each other, an interrupt request signal having the highest priority level can be detected from the competing interrupt requests with only (n+1) timings.