Automatic signal configuration
First Claim
1. A system for determining whether valid digital information is present of a digital line based upon the analog nature of said digital line, the system comprising:
- a generator adapted to continuously drive an invalid logic signal onto said digital line, said invalid logic signal capable of being overdriven by a valid logic signal on said digital line; and
a detector connected to said digital line and adapted to determine whether said valid logic signal is present on said digital line.
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Accused Products
Abstract
A system and method are disclosed for automatically configuring the interconnection of circuit boards in slots on the backplane of a computer. Some signal lines, such as bus grant and interrupt acknowledge signals, must be daisy-chained, or connected in series through the circuit boards collectively. However, if a circuit board is not present, then the daisy-chain is broken. For each slot to be monitored in the backplane, the present invention envisions implementing a generator, a valid logic level detector and a signal selector. The generator imposes an invalid logic signal onto an output connector of a slot to derive an input for the valid logic level detector. Based upon the input, the detector determines whether a circuit board resides in the slot. Accordingly, the detector adjusts the signal selector to either bypass the slot or connect the slot, as well as the present circuit board, to the daisy-chain.
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Citations
20 Claims
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1. A system for determining whether valid digital information is present of a digital line based upon the analog nature of said digital line, the system comprising:
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a generator adapted to continuously drive an invalid logic signal onto said digital line, said invalid logic signal capable of being overdriven by a valid logic signal on said digital line; and a detector connected to said digital line and adapted to determine whether said valid logic signal is present on said digital line. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A system for automatically configuring the interconnection of circuit boards interfaced to a backplane in a computer to thereby maintain a daisy-chain configuration, the system comprising:
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generator means for continuously driving an invalid logic signal onto an output of a slot for a circuit board, said invalid logic signal capable of being overdriven by said output of said circuit board when said output comprises a valid logic signal; detector means for receiving said output and for determining whether said output is either within a predetermined valid logic range or a predetermined invalid logic range; and selector means responsive to said detector, said selector means for bypassing daisy-chain lines of said slot when said output resides within said predetermined invalid logic range, said selector means for connecting said daisy-chain lines of said slot within said daisy-chain when said output resides within said predetermined valid logic range. - View Dependent Claims (14, 15, 16, 17, 18, 19)
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20. A method for determining whether valid digital information is present on a digital line based upon the analog signal level of said digital line, the method comprising the steps of:
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(1) driving an invalid logic signal onto said digital line wherein said invalid logic signal is capable of being overdriven by a valid logic signal on said digital line; (2) detecting the signal level on said digital line; )3) determining whether said level falls within either a predefined invalid logic range of a predefined valid logic range; and (4) concluding that no valid digital information resides on said digital line when said signal level is determined to be within said predefined invalid logic range.
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Specification