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. 04, 2014
Filed:
Jul. 08, 2011
Naoshi Ishikawa, Kanagawa, JP;
Naoshi Ishikawa, Kanagawa, JP;
Renesas Electronics Corporation, Kanagawa, JP;
Abstract
Disclosed is a microcomputer that can gain bus access irrespective of the magnitude relationship between the frequency of a bus master and the frequency of a bus slave. A CPU operates in accordance a first clock, which has a variable frequency. A timer operates in accordance with a second clock. A frequency conversion logic circuit is coupled to the CPU through a main bus and coupled to the timer through a peripheral I/O bus. When the first clock is higher in frequency than the second clock, the frequency conversion logic circuit generates a bus control signal for the timer by using a first synchronization signal, which indicates the change timing of a bus control signal for the peripheral I/O bus. When the first clock is lower in frequency than the second clock, the frequency conversion logic circuit generates a bus control signal for the CPU by using a second synchronization signal, which indicates the change timing of a bus control signal for the main bus. Therefore, bus access can be gained irrespective of the magnitude relationship between the frequencies of the CPU and timer.