Synchronized fault tolerant reset
First Claim
1. A synchronizing circuit comprising a plurality of modules for receiving respective asynchronous input signals and respective local clock signals, each module comprising:
- a de-metastabilizer stage for receiving the input signal and the local clock signal of said module and providing a first stage output signal representative of the input signal synchronized to the local clock signal, said first stage output signal being free of glitches and metastable conditions,a global synchronizing means for receiving the first stage output signal of the de-metastabilizer stage of each module and the local clock signal of said module and providing respective second stage output signals synchronized to the local clock signal, each second stage output signal being representative of the respective first stage output signal of an associated de-metastabilizer stage as synchronized to the local clock signal of said module, anda majority edge detector and voter network for receiving the second stage output signals of the global synchronizing means of said module and outputting and holding a voted output signal upon receiving from the global synchronizing means of said module a majority of enabling edge transitions of the second stage output signals.
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Accused Products
Abstract
A synchronizing circuit comprises a plurality of substantially identical modules for receiving respective asynchronous input signals and respective local clock signals with the local clock signals of the respective modules being substantially synchronized. Each module of the synchronizing circuit comprises a de-metastabilizer stage, a global synchronizing stage and a majority edge detector and voter network. The de-metastabilizer stage receives the input signal of the module and provides an output signal free of glitches and metastable conditions, synchronized to the local clock signal. The global synchronizing stage receives the output signals of the de-metastabilizer stage of each module and provides respective output signals synchronized to the local clock signal. The majority edge detector and voter network receives the output signals of the global synchronizing stage and outputs a voted output signal synchronized to the other modules'"'"' voted output signals and to the local clock signal.
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Citations
12 Claims
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1. A synchronizing circuit comprising a plurality of modules for receiving respective asynchronous input signals and respective local clock signals, each module comprising:
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a de-metastabilizer stage for receiving the input signal and the local clock signal of said module and providing a first stage output signal representative of the input signal synchronized to the local clock signal, said first stage output signal being free of glitches and metastable conditions, a global synchronizing means for receiving the first stage output signal of the de-metastabilizer stage of each module and the local clock signal of said module and providing respective second stage output signals synchronized to the local clock signal, each second stage output signal being representative of the respective first stage output signal of an associated de-metastabilizer stage as synchronized to the local clock signal of said module, and a majority edge detector and voter network for receiving the second stage output signals of the global synchronizing means of said module and outputting and holding a voted output signal upon receiving from the global synchronizing means of said module a majority of enabling edge transitions of the second stage output signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A fault tolerant computer system comprising a plurality of modules for receiving respective asynchronous reset signals and respective local clock signals, each module comprising:
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a de-metastabilizer stage for firstly synchronizing the reset signal of said module to the local clock signal, a global synchronizing means for receiving the firstly synchronized reset signal from the de-metastabilizer stage of each of said plurality of modules and secondly synchronizing the firstly synchronized reset signals to the local clock signal, a majority edge detector and voter network having a plurality of input terminals for receiving the secondly synchronized reset signals from the global synchronizing means of said module, and an output terminal for outputting a voted reset signal representative of the majority of the secondly synchronized reset signals, the majority edge detector and voter network providing said voted reset signal which is held in a given state upon receiving a majority of enabling edge transitions of the secondly synchronized reset signals from the global synchronizing means of said module, third synchronizing means for arming and disarming the majority edge detector and for synchronizing the voted reset signal to the local clock signal, and computer means for receiving as inputs the local clock signal and the synchronized voted reset signal. - View Dependent Claims (11, 12)
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Specification