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:
May. 11, 1999
Filed:
Aug. 18, 1997
Kelvin E McCollough, Austin, TX (US);
Javier Saldana, Austin, TX (US);
Pamela Daniel, Austin, TX (US);
Motorola Inc., Austin, TX (US);
Abstract
Under software control, a loss of clock detect circuit (24) can be enabled to detect loss of clock. A plurality of different clock signals, including the input reference clock (34) to the PLL (12) and the feedback (36) from the PLL (12), are monitored by the loss of clock circuit (24). When the currently selected system clock (38) signal is lost, a control circuit (28) can select an optimal back-up clocking mode based on which clock signals were lost. One such selectable mode is to utilize the input reference clock (34) directly instead of the PLL (12). Another such selectable mode is to utilize the PLL (12) in a self-clocked mode to provide the system clock (38).