Abstract: A method, apparatus, and computer instructions for managing a set of signal paths for a chip. A defective signal path within the set of signal paths for the chip is detected. Signals are re-routed through the set of signal paths such that the defective signal path is removed from the set of signal paths and sending signals using remaining data signal paths in the set of signal paths and using an extra signal path in response to detecting the defective signal path.

Abstract: A cascaded interconnect system with one or more memory modules, a memory controller and a memory bus that utilizes periodic recalibration. The memory modules and the memory controller are directly interconnected by a packetized multi-transfer interface via the memory bus and provide scrambled data for use in the periodic recalibration.

Abstract: A cascaded interconnect system with one or more memory modules, a memory controller and a memory bus that utilizes periodic recalibration. The memory modules and the memory controller are directly interconnected by a packetized multi-transfer interface via the memory bus and provide scrambled data for use in the periodic recalibration.

Abstract: On-chip sensor to detect power supply vulnerabilities. The on-chip sensor employs a sensitive delay chain and an insensitive delay chain to detect power supply undershoots and overshoots without requiring external off-chip components. Undershoots and overshoots outside a user-defined threshold are detected. The undershoots and overshoots are indicated by a relative difference in phase of the two delay chains. The two delay chains are programmable to detect various frequencies.

Abstract: A dual inline memory module (DIMM) includes a card having a length of about 151.2 to about 151.5 millimeters, a plurality of individual local memory devices attached to the card, and a buffer device attached to the card, the buffer device configured for converting a packetized memory interface. The card includes at least 276 pins configured thereon including a plurality of high-speed bus interface pills arranged on said card for communicating with a plurality of high-speed busses. The high-speed bus interface pins associated with a single high-speed bus are located on one side of the card with respect to a midpoint of the length of the card, thus the pin assignments are defined such that the performance of the DIMM in a system is optimized for high frequency operation.

Abstract: A dual inline memory module (DIMM) includes a card having a length of about 151.2 to about 151.5 millimeters, a pluality of individual local memory devices attached to the card, and a buffer device attached to the card, the buffer device configured for converting a packetized memory interface. The card includes at least 276 pins configured thereon.

Abstract: A system, method and storage medium for deriving clocks in a memory system. The method includes receiving a reference oscillator clock at a hub device. The hub device is in communication with a controller channel via a controller interface and in communication with a memory device via a memory interface. A base clock operating at a base clock frequency is derived from the reference oscillator clock. A memory interface clock is derived by multiplying the base clock by a memory multiplier. A controller interface clock is derived by multiplying the base clock by a controller multiplier. The memory interface clock is applied to the memory interface and the controller interface clock is applied to the controller interface.

Abstract: An interface alignment pattern for de-skewing data bits received on an elastic interface is disclosed. The interface alignment pattern is “busy” in that it has a high number of logic state transitions. The busy interface alignment pattern can be used for scrambling and unscrambling operational data. The interface alignment pattern has a unique timing sequence for determining the location of a data bit's first data beat.

Abstract: Pseudo-differential drivers and receivers are used to communicate data signals between two or more IC chips. The data paths are aligned using programmable delay circuitry to de-skew each data path. A programmable reference generator is used to generate a reference voltage used by one or a group of receivers to detect the data signals. The reference voltage is adjustable using coarse as well as fine digitally controlled voltage increments. Test signals are sent from the driver to the receiver and the reference voltage is varied over its adjustable range using the coarse and fine adjustment controls while circuitry determines a measure of the detection timing jitter on successive transitions of the test signal. The operational value of the reference voltage is set to the value where the detection timing jitter is determined to be a minimum.

Abstract: A mechanism for de-skewing and aligning data bits sent between two chips on an elastic interface. On the receiving end of an elastic interface, the eye of each data bit within a clock/data group is delayed by less than a bit time to align the eyes with the nearest clock edge of a received clock signal. In addition to aligning the eyes of the individual data bits with the nearest clock edge, IAP patterns are used to determine the amount of further delay needed to line up the individual data beats from each data bit. If the data beats for the data bits are not aligned, all but the slowest data beat are delayed to align the data beats for all bits. The additional delay is achieved using sample latches that result in a delayed signal with less jitter. As a result of having less jitter, the received, de-skewed, and aligned clock/data group can be forwarded to the operative portion of the receiving chip at an increased frequency.

Abstract: Methods and apparatus are disclosed for aligning received data bits in elastic interface systems. Depending upon which one of several alignment modes is selected, data bits can be loaded into FIFO latches on rising clock edges if the data was sent on rising clock edges, on falling clock edges if the data was sent on falling clock edges, or on the nearest clock edge if minimum latency is desired. Alternatively, data bits can be delayed by one or more bit times before loading into FIFO latches to reduce the elastic interface system's sensitivity to drift. The present invention permits a user to trade off factors related to for latency, drift, and skew by choosing among different alignment modes in an elastic interface system.

Abstract: Data signals are transmitted over transmission lines in groups to receivers in a receiving IC. Each group of data signals has a differential clock used in synchronizing and detecting the data signals. The data signal eye windows vary with timing jitter in the data signals relative to the clock edges and the asymmetry in a compensated clock signal detected from the differential clock using a duty cycle adjustment circuit. Error detection determines if the clock asymmetry is affecting the eye window of the data signals. Control signals selectively adjust the gain of differential stages generating the compensated clock to modify the duty cycle of the compensated clock. The eye window of the data signals are monitored and used as feedback to servo the control signals to optimize the duty cycle of the compensated clock signal for sampling the data signals.

Abstract: Delay elements and delay lines having glitchless operation are disclosed. By way of example, apparatus for delaying an input signal comprises a reference current generator for generating a constant current, wherein the constant current is insensitive to a variation of a power supply voltage, at least one variable bias voltage generator coupled to the reference current generator for generating a set of bias voltages based on the constant current generated by the reference current generator and a digitally programmable delay control input, and at least one delay element coupled to the at least one variable bias voltage generator for delaying the input signal by a constant delay which is determined by the set of bias voltages generated by the at least one variable bias voltage generator.

Abstract: A method and apparatus for de-skewing and aligning digital data received over and elastic interface bus is disclosed. Upon receiving the data, it is sent through a programmable delay line. While in the programmable delay line, the data is sampled at three points within the data's eye pattern. The three sampling points are dynamically adjusted to maximize coverage of the data's eye pattern. During the adjustment of the sampling points to optimally cover the data's eye pattern, delayed data is sampled from an alternate sampler to prevent sampling from the functional sampler while the delay in the primary sampler is adjusted. Sampling from the alternate sampler while changing the sampling points of the functional sampler serves to reduce glitches that may occur by sampling the functional sampler while its sampling parameters are changed. The method and apparatus allow for alternate eye tracking and wraparound eye tracking.

Abstract: A power supply voltage insensitive delay element is provided that enables a digital signal to be delayed without variation due to power supply vulnerabilities. Current is limited through the transistors of the delay element using bias voltages produced by a bias voltage generator coupled to the delay element. The bias voltage generator and the delay element are included in a delay line which facilitates the providing of a delay that is insensitive to voltage fluctuations.

Abstract: An apparatus and method for accurately tuning the speed of an integrated circuit, i.e. a computer chip, using a built-in sense circuit and controller are provided. The sense circuit is provided in association with a monitored path. The sense circuit includes a variable delay element coupled to a controller. A data signal from the monitored path is provided to the sense circuit which adds an amount of delay as determined by the controller to the data signal. The delayed data signal and the original data signal are compared to determine if their values match. If they match, then the amount of delay added by the variable delay element is increased. If they do not match, then a previous amount of delay, prior to the mismatch, is output as the slack of the monitored path. The slack may then be used to tune the speed of the integrated circuit.

Abstract: A cascaded interconnect system with one or more memory modules, a memory controller and a memory bus that utilizes periodic recalibration. The memory modules and the memory controller are directly interconnected by a packetized multi-transfer interface via the memory bus and provide scrambled data for use in the periodic recalibration.

Abstract: A memory subsystem that includes segment level sparing. The memory subsystem includes a cascaded interconnect system with segment level sparing. The cascaded interconnect system includes two or more memory assemblies and a memory bus. The memory bus includes multiple segments and the memory assemblies are interconnected via the memory bus.

Abstract: A termination network has multiple resistors forming multiple voltage dividers with a common node. Half of the resistors are coupled to the positive power supply voltage with P channel field effect transistors (PFETs) and the other half are coupled to the negative or ground power supply voltage with N channel FETs (NFETs). Logic signals are used to control the gates of the FETs. By modifying which FETs are ON, the termination network can be selectively controlled to produce various offset levels with the same impedance level. The impedance levels may also be modified while maintaining the same offset level. A delay circuit may be selectively employed to feedback control signals after a selected delay time to adjust the threshold level to dynamically or statically optimize signal reception.

Abstract: A method and apparatus are disclosed for initiating a start-up operation of a system (1′) having a master device (1) and a slave device (14a-14n). The method comprises steps of: A) exercising the slave device (14a-14n) using the master device (1) to determine a temporal range within which temporal relationships of electrical signals need to be set in order to operate the system (1′) without error; B) setting the temporal relationships of the electrical signals so as to be within the determined temporal range; and C) storing a record of the determined temporal range, for subsequent use in operating the system (1′). In one embodiment of the invention, the system (1′) includes a memory control system of a computer system (1″), and the slave device (14a-14n) includes memory devices of the computer system (1″).