Communication interface
First Claim
1. A communication interface for use in a communication system interconnecting a computer with at least one other device, said interface comprising:
- (a) output circuitry for outputting messages, said output circuitry including control circuitry and encoding circuitry for providing two parallel outputs,(i) one of said parallel outputs being in the form of an outgoing data signal representing data and including a serial bit pattern forming at least part of an output message, said serial bit pattern providing a sequence of signal transitions between two levels with said transitions occurring only when said data changes, and(ii) another one of said parallel being in the form of an outgoing strobe signal which, when data is output in the data signal, has signal transitions only at bit boundaries where there is no transition on the data signal, and(b) input circuitry for inputting messages, said input circuitry including decoding circuitry having a first input to receive an incoming data signal and a second input to receive an incoming strobe signal, said decoding circuitry being arranged to respond both to incoming data and incoming strobe signals to decode data encoded in said incoming data signal.
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Accused Products
Abstract
A communication interface for interconnecting a computer with at least one other device has a link output circuit and a link input circuit. A link output on one device is connected to a link input on another device by a data line and a parallel strobe line. Data is transmitted on the data line in serial bit strings forming a succession of tokens of predetermined lengths. Signal transitions are provided on the parallel strobe line where no signal transition occurs on the data line. Each token includes a bit indicating the length of the token and a parity bit providing a check on bits in a preceding token.
121 Citations
37 Claims
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1. A communication interface for use in a communication system interconnecting a computer with at least one other device, said interface comprising:
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(a) output circuitry for outputting messages, said output circuitry including control circuitry and encoding circuitry for providing two parallel outputs, (i) one of said parallel outputs being in the form of an outgoing data signal representing data and including a serial bit pattern forming at least part of an output message, said serial bit pattern providing a sequence of signal transitions between two levels with said transitions occurring only when said data changes, and (ii) another one of said parallel being in the form of an outgoing strobe signal which, when data is output in the data signal, has signal transitions only at bit boundaries where there is no transition on the data signal, and (b) input circuitry for inputting messages, said input circuitry including decoding circuitry having a first input to receive an incoming data signal and a second input to receive an incoming strobe signal, said decoding circuitry being arranged to respond both to incoming data and incoming strobe signals to decode data encoded in said incoming data signal. - View Dependent Claims (4, 6, 7, 10, 11, 12, 13)
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2. A communication interface for use in a communication system interconnecting a computer with at least one other device, said interface comprising:
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(a) output circuitry for outputting messages, said output circuitry including (i) control circuitry and encoding circuitry for encoding and outputting a succession of encoded serial tokens each including a serial bit string, and (ii) a parity bit generator responsive to successive bits in an encoded serial token and arranged to generate a parity bit after encoding of each serial token, said parity bit being included in a next serial token to provide a parity check responsive to the bits in the preceding serial token, and (b) input circuitry for inputting messages, said input circuitry including decoding circuitry for inputting and decoding data in each serial token received and a parity checking circuit to detect a parity bit in each serial token and compare said parity bit with a bit pattern including bits from said preceding serial token. - View Dependent Claims (5)
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3. A communication interface for use in a communication system interconnecting a computer with at least one other device, said interface comprising:
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(a) output circuitry for outputting messages, said output circuitry including (i) control circuitry and encoding circuitry for encoding and outputting a succession of variable bit length tokens each including a serial bit string including at least one parity bit and other bits including at least one bit forming a bit length indicator for the token, and (ii) a parity bit generator responsive to successive said other bits after a bit length indicator in a first token up to and including a bit length indicator in a second token and arranged to generate a parity bit for inclusion in each token, and (b) input circuitry for inputting messages, said input circuitry including decoding circuitry for inputting and decoding data in each token received and a parity checking circuit to detect a parity bit in each token and compare said parity bit with a bit pattern after a bit length indicator in one token up to and including the next bit length indicator. - View Dependent Claims (8, 9, 14, 15)
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16. A method of effecting communication between at least two interconnected devices, at least one of which devices comprises a computer device, said method comprising the steps of:
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(a) establishing parallel data signal and strobe signal communication paths between two link interfaces each connected to a respective one of said devices, (b) encoding a serial bit pattern to form a data signal representing data as at least part of an output message, said serial bit pattern providing a sequence of signal transitions between two levels with said transitions occurring only when said data changes, (c) outputting said data signal on the data signal path from one link interface, (d) outputting on the strobe signal path from the said one link interface a strobe signal which, when data is output in the data signal transitions only at bit boundaries where there is no transition on the data signal, and (e) inputting said data and strobe signals in parallel at the other link interface and responding to both said data and strobe signals to decode data encoded in said data signal. - View Dependent Claims (21, 22, 23, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37)
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17. A method of effecting communication between at least two interconnected devices, at least one of which devices comprises a computer device, said method comprising the steps of:
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(a) establishing unidirectional communication paths between two link interfaces each connected to a respective one of said devices, (b) encoding a succession of tokens each including a serial bit string, (c) generating a parity bit in response to successive bits of a first token, (d) including said parity bit in the serial bit string of a second token following said first token to provide a check on the number of bits in said first token, (e) transmitting said first and second tokens serially from one said link interface to the other link interface, (f) decoding said first and second tokens at said other link interface, and (g) detecting said parity bit in said second token and comparing said parity bit with the decoded bit pattern.
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18. A method of effecting communication between at least two interconnected devices, at least one of which devices comprises a computer device, said method comprising the steps of:
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(a) establishing unidirectional communication paths between two link interfaces each connected to a respective one of said devices, (b) encoding a succession of variable length tokens each including a serial bit string including at least one parity bit and other bits including a token bit length indicator, (c) generating a parity bit in response to successive bits of a first token following a bit length indicator for said first token up to and including a bit length indicator for a next token, (d) including said parity bit in the serial bit string of said next token to provide a check on bits in said first token and the bit length indicator of said next token, (e) transmitting said first and second tokens serially from one said link interface to the other link interface, (f) decoding said first and next tokens at said other link interface to provide a decoded bit pattern, and (g) detecting said parity bit and comparing said parity bit with the decoded bit pattern. - View Dependent Claims (19, 20, 24, 25, 26)
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Specification