Three-state differential data transmission with self latching ability
AssigneeAgilent Technologies, Inc.
InventorSHAD R. SHEPSTON
Life of this patent
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Abstract
Digital data transmission using three logic states on a differential pair of signal lines. The three states are: a first line a threshold higher than a second line, the second line a threshold higher than the first line, and when both lines are approximately equal. The presence of three states allows the receiving circuit to recognize the beginning and end of a valid data bit. A receiving circuit using two comparators to generate strobes for latching the data is also disclosed. The strobes also clock a counter whose output is fed to a decoder. The output of the decoder is used to select one of N latches that are used to latch the incoming data.
Claims8
Digital data transmission, comprising:
- a first signal line having a first signal wherein said first signal assumes a first signal value when a first data bit value is being transmitted and said first signal assumes a second signal value when a second data bit value is being transmitted and said first signal assumes a third signal value when no data is being transmitted;
- a second signal line having a second signal wherein said second signal assumes said first signal value when said second data bit value is being transmitted and said second signal assumes said second signal value when said first data bit value is being transmitted and said second signal assumes said third signal value when no data is being transmitted;
- and
- a strobe signal, said strobe signal indicating when said first data bit value and said second data bit value should be latched, said strobe signal being generated from a difference between said first signal and said second signal.
Digital data transmission, comprising:
- a first signal line having a first signal wherein said first signal assumes a first signal value when a first data bit value is being transmitted and said first signal assumes a second signal value when a second data bit value is being transmitted and said first signal assumes said second signal value when no data is being transmitted;
- a second signal line having a second signal wherein said second signal assumes said first signal value when said second data bit value is being transmitted and said second signal assumes said second signal value when said first data bit value is being transmitted and said second signal assumes said second signal value when no data is being transmitted;
- and
- a strobe signal, said strobe signal indicating when said first data bit value and said second data bit value should be latched, said strobe signal being generated from a difference between said first signal and said second signal.
A method of transmitting digital data, comprising:
- driving a first signal to a first signal value to transmit a first data bit value;
- driving said first signal to a second signal value to transmit a second data bit value;
- driving said first signal to a third signal value when no data is being transmitted;
- driving a second signal to the second signal value to transmit said first data bit value;
- driving said second signal to the first signal value to transmit a second data bit value;
- driving said second signal to the third signal value when no data is being transmitted;
- and
- generating a strobe, said strobe being generated by a difference between said first signal and said second signal;
- latching said first data bit value and said second data bit value using said strobe.
A method of transmitting digital data, comprising:
- driving a first signal to a first signal value to transmit a first data bit value;
- driving said first signal to a second signal value to transmit a second data bit value;
- driving said first signal to the second signal value when no data is being transmitted;
- driving a second signal to the second signal value to transmit said first data bit value;
- driving said second signal to the first signal value to transmit a second data bit value;
- driving said second signal to the second signal value when no data is being transmitted;
- and
- generating a strobe, said strobe being generated by a difference between said first signal and said second signal;
- latching said first data bit value and said second data bit value using said strobe.
Dependencies are inferred from the claim text.