Programmable interface circuit for differential and single-ended signals
AssigneeLattice Semiconductor Corporation
InventorArifur Rahman
Life of this patent
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Abstract
A programmable interface circuit is disclosed, in accordance with one embodiment, which supports differential and single-ended signaling. For example, an input buffer within the programmable interface circuit is configurable to receive differential signals or single-ended signals. A multiplexer provides the appropriate reference signal to the input buffer, when configured to receive single-ended signals, by selecting the reference signal from a plurality of reference buses. The multiplexer, along with a capacitor, may also provide lowpass filtering of the reference signal. Furthermore, an output buffer may be configurable utilizing techniques similar to that described for the input buffer.
Claims19
An interface circuit comprising:
- a first input buffer having a first and a second input lead, wherein the first input lead is coupled to a first terminal;
- a plurality of reference buses adapted to provide reference signals;
- a first multiplexer, coupled to the plurality of reference buses, adapted to provide one of the reference signals from the plurality of reference buses as its output signal;
- and
- a second multiplexer, coupled to the first input buffer and the first multiplexer, adapted to provide to the second input lead the output signal from the first multiplexer or an input signal from a second terminal.
An integrated circuit comprising:
- a first input buffer having a first and second lead, wherein the first lead is coupled to a first terminal;
- a second input buffer having a third and fourth lead, wherein the fourth lead is coupled to a second terminal;
- means for providing a plurality of reference signals;
- means for providing one of the plurality of reference signals to the second lead of the first input buffer or coupling the second lead to the second terminal;
- and
- means for providing one of the plurality of reference signals to the third lead of the second input buffer or coupling the third lead to the first terminal.
A method for receiving differential and single-ended signals, the method comprising:
- providing a differential input buffer having a first and second input lead;
- coupling a first input signal path to the first input lead;
- and
- providing a configurable path to the second input lead, wherein the configurable path can be configured to provide a second input signal path to the second input lead or configured to provide a reference signal path to the second input lead to receive a desired reference signal.
Dependencies are inferred from the claim text.