An End Of Interrupt (EOI) is a signal sent to a Programmable Interrupt Controller (PIC) to indicate the completion of interrupt processing for a given interrupt. An EOI is used to cause a PIC to clear the corresponding bit in the In-Service Register (ISR), and thus allow more interrupt requests of equal or lower priority to be generated by the PIC.
EOIs may indicate the interrupt vector implicitly, or explicitly. An explicit EOI vector is indicated with the EOI, whereas an implicit EOI vector will typically use a vector as indicated by the PICs priority schema. For example, the highest vector in the ISR. Also, EOIs may be sent at the end of interrupt processing by an interrupt handler, or the operation of a PIC may be set to auto-EOI at the start of the interrupt handler.
Famous quotes containing the word interrupt:
“Television ... helps blur the distinction between framed and unframed reality. Whereas going to the movies necessarily entails leaving one’s ordinary surroundings, soap operas are in fact spatially inseparable from the rest of one’s life. In homes where television is on most of the time, they are also temporally integrated into one’s “real” life and, unlike the experience of going out in the evening to see a show, may not even interrupt its regular flow.”
—Eviatar Zerubavel, U.S. sociologist, educator. The Fine Line: Making Distinctions in Everyday Life, ch. 5, University of Chicago Press (1991)