Browse Prior Art Database

Activity clock detector

IP.com Disclosure Number: IPCOM000013290D
Original Publication Date: 2000-Aug-01
Included in the Prior Art Database: 2003-Jun-18
Document File: 2 page(s) / 47K

Publishing Venue

IBM

Abstract

I. Problem Description The problem to fix is, in a system generating clocks for a slave part, how to control if these clocks are really sent to the external.

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Activity clock detector

I. Problem Description The problem to fix is, in a system generating clocks for a slave part, how to control if these clocks are really sent to the external.

II. Applications of the Invention Any machine or system wanting to sent reference clocks safely.

III. Description of the Invention As described on figure 1, a clock is generated by the VCXO. A clock buffer gives more power to feed several adapters, and one module is used to monitor the clock sent. This module is connected to the input of the activity detector, and the "detect" output of the activity detector is connected to the interrupt input of a microcontroller of the reference card.

CLOCK BUFFER

REFERENCE CARD

ADAPTER

VCXOCHIP

ADAPTER CARD

In

 ACTIVITY DETECTOR

detect

  MICRO CONTROLLER

Interrupt

FIGURE 1

On the figure 2 , the schematic of the clock activity detector

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shows that the CLOCK to be MONITORED is connected to the input of a UP TRANSITION SYSTEM used to reset a COUNTER . This COUNTER counts up to the 5 , this number is the max clock count time used (it can be set to different values depending of the application). The COUNTER is clocked by a system clock as for a SET/RESET mechanism. The SET/RESET is reset by the up transition system , and if everything is OK, the DETECT output is always inactive (=0). If the CLOCK to be MONITORED is missing, after 5 time SYSTEM CLOCKS , the COUNT END output is raised , and...