Abstract: A technique for characterizing a communications interface includes determining a voltage margin and a timing margin of the interface based on data sampled by a sampling device of a receiver of the interface. In at least one embodiment of the invention, a method for determining margin associated with a receiver circuit of an integrated circuit includes periodically sampling a signal over a time period by a receiver sampling circuit of the receiver circuit to generate a sampled version of the signal. The method includes incrementally varying a value of the parameter associated with the signal. The varying of the parameter is through a range of values of the parameter over the time period. The method includes determining a margin value of the receiver circuit associated with the parameter based, at least in part, on the sampled version of the signal.

Abstract: A decision feedback equalization (DFE) receiver and method are provided. The DFE receiver is configured to sample data bits from a data bus. The DFE receiver includes a data sampler configured to sample a current data bit from the data bus using one of a first, second and third voltage reference. The DFE receiver also includes multiplexing logic configured to select one of the first, second and third voltage references based on a prior data bus level. The wherein the first voltage reference is selected if the prior data bus level was a logic zero. The second voltage reference is selected if the prior data bus level was a logic one. The third voltage reference is selected if the prior data bus level was tri-state.

Abstract: A data processing device is configured so that, in a test mode of operation, the phase of an output signal of a second programmable delay module (PDM) is based on the phase of the input signal of the first PDM. To test the first and second PDMs, the output signal of the first PDM is set to each of a first set of phases and the corresponding phase of the output signal of the second PDM is compared to determine whether the performance of the first and second PDMs match a specification. Accordingly, the first and second PDMs are qualified based on their relative performance, reducing the need for test structures that consume an undesirably large amount of area.

Abstract: A decision feedback equalization (DFE) receiver and method are provided. The DFE receiver is configured to sample data bits from a data bus. The DFE receiver includes a data sampler configured to sample a current data bit from the data bus using one of a first, second and third voltage reference. The DFE receiver also includes multiplexing logic configured to select one of the first, second and third voltage references based on a prior data bus level. The wherein the first voltage reference is selected if the prior data bus level was a logic zero. The second voltage reference is selected if the prior data bus level was a logic one. The third voltage reference is selected if the prior data bus level was tri-state.

Abstract: A memory controller including a dual-mode memory interconnect includes an input/output (I/O) circuit including a plurality of input buffers and a plurality of output drivers. The I/O circuit may be configured to operate in one of a first mode and a second mode dependent upon a state of a mode selection signal. During operation in the first mode, the I/O circuit may be configured to provide a parallel interconnect for connection to one or more memory modules. During operation in the second mode, the I/O circuit may be configured to provide a respective serial interconnect for connection to each of one or more buffer units, each configured to buffer memory data that is being read from or written to the one or more memory modules.

Abstract: A technique for reducing crosstalk between communications paths includes scrambling data using scrambling functions that reduce or substantially minimize a probability that worst-case data patterns occur on communications paths adjacent to a potential victim communications path. In at least one embodiment of the invention, a method includes scrambling a plurality of data bits based at least in part on respective ones of a plurality of distinct combinations of one or more taps of a linear feedback shift register (LFSR). The plurality of data bits are scrambled for transmission during a first bit-time on corresponding ones of a plurality of adjacent communications paths.

Abstract: An in-band configuration technique configures a data communications link for high-speed data communications between at least a first and second integrated circuit using in-band communications between the first and second integrated circuits. The technique configures at least one equalizer of the data communications link with predetermined equalizer settings selected from a plurality of predetermined equalizer settings based on a selected rate of data communications for the link.

Abstract: A memory subsystem includes a master controller that includes a pseudo random bit sequence (PRBS) generator having a plurality of output taps and an exclusive-OR (XOR) unit. The memory subsystem also includes a memory device that is coupled to the master controller via a plurality of single ended bidirectional data paths. The master controller may scramble a plurality of data bits using the PRBS generator and the XOR unit prior to writing the plurality of data bits to the memory device. In addition, the master controller may perform an XOR between each bit of the plurality of data bits and a respective output tap of the PRBS generator prior to conveyance on a respective path of the plurality of single ended bidirectional data paths.

Abstract: A memory system including asymmetric high-speed differential memory interconnect includes one or more buffer units coupled to one or more memory units such as memory modules, for example, via a parallel interconnect. The memory system also includes a memory controller coupled to each of the buffer units via a respective serial interconnect. The memory controller may control data transfer between the memory controller and the one or more buffer units. During normal operation, each of the buffer units may be configured to receive data from the memory controller via the respective serial interconnect and to transmit the data to the one or more memory units via the parallel interconnect, in response to receiving command information from the memory controller. Further, the memory controller may be configured to modify a phase alignment of information transmitted from the memory controller based upon information received from the buffer units.

Abstract: A memory controller including a dual-mode memory interconnect includes an input/output (I/O) circuit including a plurality of input buffers and a plurality of output drivers. The I/O circuit may be configured to operate in one of a first mode and a second mode dependent upon a state of a mode selection signal. During operation in the first mode, the I/O circuit may be configured to provide a parallel interconnect for connection to one or more memory modules. During operation in the second mode, the I/O circuit may be configured to provide a respective serial interconnect for connection to each of one or more buffer units, each configured to buffer memory data that is being read from or written to the one or more memory modules.

Abstract: A system for controlling high-speed bidirectional communication includes a slave device such as a memory device, for example, coupled to a master device such as a memory controller, for example. The master device may be configured to control data transfer between the master device and the slave device. The master device may be configured to provide one or more clock signals to the slave device and during an initialization mode, the master device may modify a phase alignment of the one or more clock signals. Further the master device may subsequently modify a phase alignment of data transmitted from the master device based upon information received from the slave device.

Abstract: A data processing device is configured so that, in a test mode of operation, the phase of an output signal of a second programmable delay module (PDM) is based on the phase of the input signal of the first PDM. To test the first and second PDMs, the output signal of the first PDM is set to each of a first set of phases and the corresponding phase of the output signal of the second PDM is compared to determine whether the performance of the first and second PDMs match a specification. Accordingly, the first and second PDMs are qualified based on their relative performance, reducing the need for test structures that consume an undesirably large amount of area.

Abstract: A system including asymmetric control of high-speed bidirectional signaling includes a slave device and a master device that is coupled to the slave device via a plurality of bidirectional data paths, for example. The master device may control data transfer between the master device and the slave device. More particularly, the master device may adaptively modify transmit characteristics subsequent to adaptively modifying receiver characteristics based upon information received from the slave device via one or more unidirectional data paths.

Abstract: A system for protecting data during high-speed bidirectional communication between a master device and a slave device. The master device may control data transfer between the master device and the slave device. In addition, the master device may perform a read request to the slave device for a first data block associated with a first address and a second data block associated with a second address. In response, the slave device may send to the master device a portion of the first data block in a first burst and a portion of the second data block in a second burst via a plurality of bidirectional data paths. The slave device may further generate and send to the master device via one or more unidirectional data paths a cyclic redundancy code (CRC) based upon the first data block and the second data block.

Abstract: A memory controller including a dual-mode memory interconnect includes an input/output (I/O) circuit including a plurality of input buffers and a plurality of output drivers. The I/O circuit may be configured to operate in one of a first mode and a second mode dependent upon a state of a mode selection signal. During operation in the first mode, the I/O circuit may be configured to provide a parallel interconnect for connection to one or more memory modules. During operation in the second mode, the I/O circuit may be configured to provide a respective serial interconnect for connection to each of one or more buffer units, each configured to buffer memory data that is being read from or written to the one or more memory modules.

Abstract: A method and apparatus for crosstalk reduction. In one embodiment, an electronic system includes a transmitter and a receiver coupled by a plurality of differential signal paths. A first differential signal path is adjacent to a second differential signal path, which is adjacent to a third. Data transmitted on a first differential signal path is scrambled with a first scrambler function, while data transmitted on a third differential signal path is scrambled with a second scrambler function, which is an inverse of the first scrambler function. Data transmitted on a second differential signal path is scrambled with a third scrambler function, while data transmitted on a fourth differential signal path is scrambled with a fourth scrambler function that is an inverse of the third.

Abstract: A system for phase tracking and equalization across a byte group for asymmetric control of high-speed bidirectional signaling includes a slave device and a master device that is coupled to the slave device via a plurality of bidirectional data paths. The master device may adaptively modify transmit characteristics based upon data eye information sent via one or more unidirectional data paths by the slave device. The data eye information may correspond to an edge position of data signal transitions received by the slave device on each data path of the plurality of bidirectional data paths. In addition, the master device may modify data path equalization coefficients within the master device for a grouping of the bidirectional data paths such as a byte group, for example, dependent upon the data eye information.

Abstract: A system including input offset correction for asymmetric control of high-speed bidirectional signaling includes a slave device and a master device that is coupled to the slave device. The master device may control data transfer between the master device and the slave device. In response to the master device determining there is an input offset bias present within the slave device, the master device may adaptively modify a DC voltage offset of data transmitted by the master device based upon data eye information received from the slave device via one or more unidirectional signal paths.

Abstract: A system including a host coupled to a serially connected chain of memory modules. In one embodiment, each of the memory modules includes a memory control hub for controlling access to a plurality of memory chips on the memory module. The memory modules are coupled serially in a chain to the host via a plurality of memory links. Each memory link may include an uplink for conveying transactions toward the host and a downlink for conveying transactions originating at the host to a next memory module in the chain. The uplink and the downlink may convey transactions using packets that include control and configuration packets and memory access packets. The memory control hub may convey a transaction received on a first downlink of a first memory link on a second downlink of a second memory link independent of decoding the transaction.

Abstract: A memory controller including a dual-mode memory interconnect includes an input/output (I/O) circuit including a plurality of input buffers and a plurality of output drivers. The I/O circuit may be configured to operate in one of a first mode and a second mode dependent upon a state of a mode selection signal. During operation in the first mode, the I/O circuit may be configured to provide a parallel interconnect for connection to one or more memory modules. During operation in the second mode, the I/O circuit may be configured to provide a respective serial interconnect for connection to each of one or more buffer units, each configured to buffer memory data that is being read from or written to the one or more memory modules.