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:
Jul. 27, 1999
Filed:
Feb. 17, 1998
Kenji Kubo, Hyogo, JP;
Hideyuki Takaoka, Hyogo, JP;
Mitsubishi Electric System LSI Design Corporation, Hyogo, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
Oscillating circuitry built in integrated circuitry (1) comprises a ring oscillator (31) for generating a first clock, an external oscillator (40) capable of generating a second clock in either one of two oscillating modes which is determined according to an external circuit (12 and 13, or 6 through 8) connected to terminals (2 and 3) thereof, and an internal clock selection circuit (41) which delivers the first clock as an internal clock to the integrated circuitry (1) just after the integrated circuitry (1) is activated or reset, stops the delivery of the first clock and simultaneously furnishes a signal held at a logic high level as the internal clock in response to a control signal for instructing a selection of the second clock, and then determines whether or not the external oscillator (40) is generating the second clock properly, and which furnishes the second clock as the internal clock when it determines that the external oscillator (40) is generating the second clock properly.