Adaptive Interrupt Sharing
Original Publication Date: 1986-Apr-01
Included in the Prior Art Database: 2005-Mar-08
This article describes an extended form of interrupt sharing for personal computer (PC) peripherals, which allows for switching between different interrupt request signalling paths, one path providing conventional PC request handling and the other providing shared request handling under control of system supervisory software. The interrupt request (IRQ) circuits for most of the existing PC I/O adapters are implemented such that when the circuit is enabled, the IRQ signal to the PC I/O channel stays "low" during the non-active state. The IRQ line is set "high" when interrupt is requested. With this mechanism, only one device can be enabled for each interrupt level. The low state device overrides the high state device.