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US 2011/0084737 A1Published application
Frequency responsive bus coding
AssigneeRambus Inc.
InventorsKyung Suk Oh, John Wilson, Joong-Ho Kim, Jihong Ren
Life of this patent
Estimating the term…
Abstract
A data system permits bus encoding based on frequency of the bus and the frequency of switching on the bus so as to avoid undesirable frequency conditions such as a resonant condition or interference with other electrical devices. Transmission frequencies along one or more busses are monitored and used to control the encoding process, for example, an encoding process based on data bus inversion (DBI). The use of both a measure of an absolute number of logic levels (“DBI_DC”) and a measure of a number of logic level transitions relative to a prior signal (“DBI_AC”) provides a measure of control that may be used to compensate for both main and predriver switching noise.
Claims43
A bus driving system, comprising:
- a first detector having a first detector output, the first detector receiving a first detector input signal that varies in time corresponding to transitions on a first plurality of signal lines;
- a second detector having a second detector output, the second detector receiving a second detector input signal that varies in time corresponding to signal line levels on a second plurality of signal lines;
- and,
- an encoder that selectively applies at least a first encoding scheme to a plurality of signal lines of a bus based on the first detector output and the second detector output.
1 more element
A method of encoding a plurality of signal lines of a bus, comprising:
- receiving, at a first detector, a first indicator, the first indicator varying in time corresponding to a first time varying number of signal line state transitions of the plurality of signal lines;
- receiving, at a second detector, a second indicator, the second indicator varying in time corresponding to a second time varying number of signal lines of the plurality of signal lines driven to a first state;
- filtering, by the first detector, the first indicator to produce a first detected signal indicator;
- filtering, by the second detector, the second indicator to produce a second detected signal indicator;
- and,
- selecting a first coding for the bus based on the first detected signal indicator and the second detected signal indicator.
3 more elements
An integrated circuit, comprising:
- a first detector to sense a first characteristic associated with internal switching for a transmission on a plurality of signal lines on a bus, the first detector generating a first indicator associated with first characteristic and the internal switching for the transmission;
- a second detector to sense a second characteristic associated with the transmission on the plurality of signal lines, the second detector generating a second indicator associated with the second characteristic and the transmission;
- an encoding controller to receive the first indicator and the second indicator, the encoding controller to select a selected encoding from at least a first encoding and a second encoding for the plurality of signal lines based on the first indicator and the second indicator;
- and,
- a bus encoder, responsive to the encoding controller, to set the selected encoding of the plurality of signal lines.
2 more elements
A computer readable medium having information stored thereon that describes a block of an integrated circuit including a bus encoder, the integrated circuit comprising:
- a first detector having a first detector output, the first detector receiving a first detector input signal that varies in time corresponding to transitions on a first plurality of signal lines;
- a second detector having a second detector output, the second detector receiving a second detector input signal that varies in time corresponding to signal line levels on a second plurality of signal lines;
- and,
- an encoder that selectively applies at least a first encoding scheme to a plurality of signal lines of a bus based on the first detector output and the second detector output.
1 more element
A system comprising:
- a predriver power supply, the predriver power supply having a predriver power supply distribution network resonance frequency;
- a signal line power supply, the signal line power supply having a signal line power supply distribution network resonance frequency;
- a plurality of signal line predrivers using the predriver power supply;
- a plurality of signal line drivers setting signal levels on a plurality of signal lines, the plurality of signal line drivers controlled by the plurality of signal line predrivers and using the signal line power supply;
- first detecting means for detecting a first frequency characteristic associated with the predriver power supply distribution network resonance frequency;
- second detecting means for detecting a second frequency characteristic associated with the signal line driver power supply distribution network resonance frequency;
- encoding selection means, coupled to the first detecting means and the second detecting means, for selecting at least a first encoding for the plurality of signal lines based on a first signal produced by the first detecting means and a second signal produced by the second detecting means;
- and,
- encoding means coupled to the plurality of signal line predrivers for controlling the plurality of signal line predrivers to set the first encoding of the plurality of signal lines.
6 more elements
A system comprising:
- a predriver power supply, the predriver power supply having a predriver power supply distribution network resonance frequency;
- a signal line power supply, the signal line power supply having a signal line power supply distribution network resonance frequency;
- a plurality of signal line predrivers using the predriver power supply;
- a plurality of signal line drivers setting signal levels on a plurality of signal lines, the plurality of signal line drivers controlled by the plurality of signal line predrivers and using the signal line power supply;
- a detector responsive to a first characteristic associated with the predriver power supply distribution network resonance frequency and a second characteristic associated with the signal line driver power supply distribution network resonance frequency;
- an encoder, responsive to the detector, coupled to the plurality of signal line predrivers that controls the plurality of signal line predrivers to set a first encoding of the plurality of signal lines.
3 more elements
Dependencies are inferred from the claim text.