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:
Aug. 27, 2002
Filed:
Nov. 16, 1999
Yasufumi Morimoto, Hyogo, JP;
Takeshi Fujii, Hyogo, JP;
Other;
Abstract
A ring oscillator clock frequency measuring circuit includes a reference clock count timer and a ring oscillator clock count timer. The reference clock count timer starts its counting of a reference clock signal in response to a start instruction fed from a CPU, and outputs an overflow signal when its counting reaches a preset value. The ring oscillator clock count timer starts its counting of pulses of a ring oscillator clock signal in response to the start instruction fed from the CPU, and continues its counting until the reference clock count timer generates the overflow signal. The frequency of the ring oscillator clock signal is obtained from the count value of the ring oscillator clock count timer. This makes it possible to measure the frequency of the ring oscillator clock signal at high accuracy, and to reduce the current consumption by operating the CPU based on the ring oscillator clock signal after the measurement.