Partial response receiver

An integrated circuit device for receiving a signal transmitted via an electrical signal conductor, the integrated circuit device comprising:

• a first sampling circuit to sample the signal and generate a first sample value that indicates whether the signal exceeds a first threshold level;
• a second sampling circuit to sample the signal and generate a second sample value that indicates whether the signal exceeds a second threshold level;
• a first select circuit coupled to receive the first and second sample values from the first and second sampling circuits and configured to select, according to a previously generated sample value, either the first sample value or the second sample value to be output as a selected sample value;
• a third sampling circuit to compare the signal with a third threshold level and to generate error samples that indicate whether the signal exceeds or is below the third threshold level;
• and
• a threshold generating circuit to adjust the third threshold level until the error samples indicate that the third threshold level substantially matches a first selected level of the signal.

A method of operation within an integrated circuit device, the method comprising:

• receiving a data signal from an external electrical signaling path;
• generating a first data sample having one of at least two states according to whether the data signal exceeds a first threshold level;
• generating a second data sample having one of the at least two states according to whether the data signal exceeds a second threshold level;
• generating an error sample that indicates whether the data signal exceeds or is below a third threshold level, wherein the first, second, and third threshold levels are generated based at least in part upon the error sample;
• and
• selecting either the first data sample or the second data sample to be a selected sample of the data signal.

A method of operation within an integrated circuit device, the method comprising:

• receiving a data signal from an external electrical signaling path;
• determining a first voltage level of the data signal;
• determining a second voltage level of the data signal;
• generating a first threshold level based on the first and second voltage levels of the data signal;
• generating a first data sample having one of at least two states according to whether the data signal exceeds the first threshold level;
• generating a second data sample having one of the at least two states according to whether the data signal exceeds a second threshold level;
• and
• selecting either the first data sample or the second data sample to be a selected sample of the data signal;
• wherein generating the first threshold level based on the first and second voltage levels comprises subtracting a value representative of the first voltage level from a value representative of the second voltage level to generate a first control value, the first control value corresponding to the first threshold level.

An integrated circuit device for receiving a signal transmitted via an electrical signal conductor, the integrated circuit device comprising:

• a first pair of sampling circuits to capture a first pair of samples of the signal in response to a first clock signal;
• a second pair of sampling circuits to capture a second pair of samples of the signal in response to a second clock signal;
• a first select circuit coupled to the first pair of sampling circuits and configured to select one sample of the first pair of samples according to a state of a selected sample of the second pair of samples;
• a second select circuit coupled to the second pair of sampling circuits and configured to select the selected sample of the second pair of samples;
• a first storage circuit coupled to receive the one sample of the first pair of samples from the first select circuit and configured to store the one sample of the first pair of samples in response to the first clock signal;
• and
• a second storage circuit coupled to receive the selected sample of the second pair of samples from the second select circuit and configured to store the selected sample of the second pair of samples in response to the second clock signal.

A method of operation within an integrated circuit device, the method comprising:

• generating first and second samples of an input data signal, each sample having either a first state or a second state according to whether the input data signal exceeds a respective one of first and second threshold levels;
• generating a first received data value based on the first and second data samples if a mode select signal is in a first state;
• and
• generating a second received data value based on the first and second data samples if the mode select signal is in a second state, wherein the second received data value includes more constituent bits than the first received data value.

A method of operation within a signaling system, the method comprising:

• outputting a sequence of data values onto an electrical signal conductor during successive transmission intervals, the sequence of data values forming a data signal on the electrical signal conductor;
• generating, during a first data reception interval, a first data sample having either a first state or second state according to whether a signal level of the electrical signal conductor exceeds a first threshold level and a second data sample having either the first state or second state according to whether the signal level exceeds a second threshold level;
• generating, during the first data reception interval, an error sample that indicates whether the signal level of the electrical signal conductor exceeds or is below a third threshold level;
• outputting, during a second data reception interval after the first data reception interval, a selected data sample, the selected data sample being selected from the first data sample and the second data sample according a data sample generated during a third data interval prior to the second data reception interval;
• and
• outputting the error sample during the second data reception interval.

An integrated circuit device for receiving signals transmitted in parallel via a data bus, the integrated circuit device comprising:

• a plurality of receive circuits to receive respective ones of the signals via respective signal lines of the data bus, the plurality of receive circuits including a first receive circuit to receive a first one of the signals from a first signal line of the data bus;
• a level sampler to sample the first one of the signals to generate at least one error sample;
• and
• an adaptive module to produce at least one pair of threshold values according to outputs from the first receive circuits and the level sampler, and to provide the at least one pair of threshold values to the plurality of receive circuits, wherein a respective receive circuit includes at least one pair of samplers to produce at least one pair of sample values of a respective signal by comparing a signal level of the respective signal with the at least one pair of threshold values, and wherein the respective receive circuit further includes selection circuitry to select one of the sample values according to a previously produced sample value.