Browse Prior Art Database

Extension to 68k Manual Vector Range

IP.com Disclosure Number: IPCOM000036815D
Original Publication Date: 1989-Oct-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 2 page(s) / 56K

Publishing Venue

IBM

Related People

Lee, KL: AUTHOR [+2]

Abstract

This article describes a technique for use in a microprocessor which provides the ability to attach more than 192 interrupts.

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Extension to 68k Manual Vector Range

This article describes a technique for use in a microprocessor which provides the ability to attach more than 192 interrupts.

Some microprocessors provide only 256 manual interrupt vectors which are insufficient for a 32-port communication controller. A generic control program (XCP) already supplies an interface for all manual vectors. This interface with some hardware assists can supply essentially 2 to the 30 number of manual vectors. This is done by having the hardware arbitrator taking all vectors higher than xxx and multiplexing them into vector xxx. Thus, whenever an interrupt that had a manual vector ID of xxx or higher occurred, an interrupt xxx would be presented to the microprocessor and the vector number would be stored in a hardware register. The XCP first level interrupt handler would then decode the vector number from the hardware register and invoke the correct application interrupt handler.

Referring to the drawing, the interrupt source will provide a vector number as a part of the microprocessor interrupt sequence. A hardware interrupt converter will then convert the raw interrupt vector number to a number less than 255 (the maximum allowed by some microprocessors). The vector number provided by the interrupting peripheral will be saved in the vector number register for later use by XCP. The converted interrupt vector number is then presented to the microprocessor. If the vector was greater than 255, vector 25...