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Enhanced diagnostics for printed circuit board

IP.com Disclosure Number: IPCOM000014158D
Original Publication Date: 2000-Jul-01
Included in the Prior Art Database: 2003-Jun-19

Publishing Venue

IBM

Abstract

Disclosed is a device logic that can check improper condition of load/unload function in HDD. Now many functions and logic are integrated in LSI module. A clock is generated and provided by a module. If the clock-provided-module has some trouble, other module cannot work properly. Checking clock speed by using 2 different clock source can avoid improper condition. To HDD, especially to spindle driver, proper clock source is important because spindle is controlled by real time operation. For example, there is a module required clock frequency is 20MHz, but provided frequency is 12MHz. In this case, spindle rotational speed can reach only 60% 12/20 speed. This cause serious trouble because the heads cannot fly high enough. In addition, even microcode or the other module cannot check the clock frequency. This invention is for checking this kind of improper clock then avoiding serious trouble. For example, there are 2 different clock like 33MHz and 50MHz, we can compare. 2 50MHz clock is equivalent to 3 33MHz clock anytime. Then it can avoid serious trouble. 1