The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 21, 1995
Filed:
Sep. 29, 1993
Norio Masui, Hyogo, JP;
Shigeo Mizugaki, Hyogo, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
A microcomputer provided with improved interrupt handling. The frequency of a clock signal supplied to the central processing unit is increased to shorten the interrupt holding time when relatively many interrupts are occurring. When few interrupts are occurring, the frequency of the clock signal is decreased thereby reducing power consumption. The invention includes a holding factors register for storing the number of interrupt factors being held by an interrupt controller and an interrupt nesting counter for storing the number of nested interrupts in the central processing unit. The numbers stored in the holding factors register and interrupt nesting counter are compared to preset numbers. A clock control circuit changes the frequency of the system clock signal in accordance with the comparison result thereby changing the frequency of the clock signal depending on the number of occurrences of interrupts.