International Business Machines Corporation

Other

Douglas J Malone

Andreas H A Arp

Michael V Koch

Thomas Makowski

Chad Andrew Marquart

Daniel Mark Dreps

Thomas J Knips

Jason Lee Frankel

James W Dawson

Franklin M Baez

Ching Lung Tong

Lily Jielu Zhang

John D Davis

Michael Sperling

Pawel Owczarczyk

Tom Y Chang

A two-chip die module with minimal chip-to-chip clock skew is provided. The two-chip die module includes a common substrate, first and second chips operably disposed on the common substrate to be communicative in parallel with one another and a single phase lock loop (PLL). The PLL is disposed within one of the first and second chips to provide a source for a common clock signal for the first and second chips. PLL signals of the PLL to the first and second chips are nearly equal and clock sample signals of the first and second chips are nearly equal.

Phase aligning and calibrating clocks from one phase lock loop (PLL) for a two-chip die module

Measuring a control system response time of a second clock tree is provided, comprising measuring a skew between the second clock signal and the first clock signal and storing the skew, initiating a delay change of a delay induced by the programmable delay line and starting a time measurement. At least one iteration is performed of measuring the skew between the second clock signal and the first clock signal and comparing the measured skew with the stored skew. Based on the result of the comparison, stopping after a current iteration and stopping the time measurement. A result of the time measurement is the control system response time.

Measuring a control system response time

A skew sensor for detecting skew between two input signals is provided. The skew sensor includes at least two skew detectors. The first skew detector receives either a first clock signal or a second clock signal as a first input signal, and the other one of the first clock signal and the second clock signal delayed by a first delay difference induced by one or more delay elements as a second input signal. The second skew detector receives either the first clock signal or the second clock signal as the first input signal, and the other one of the first clock signal and the second clock signal optionally delayed by a second delay difference induced by one more delay elements, wherein the second delay difference is different from the first delay difference, as the second input signal. Skew is measured between the first clock signal and the second clock signal.

Quantitative skew sensor

A method for cycle accurate deskewing a second clock signal with respect to a first clock signal is provided. The first clock signal has been propagated from a first clock source through a first clock tree. The second clock signal has been propagated from the first clock source through a second clock tree. The second clock tree comprises a programmable delay line for inducing a delay. The method comprises determining a first clock tree latency of the first clock tree, determining a second clock tree latency of the second clock tree, setting a cycle time of the first clock source to a measuring cycle time depending on the first clock tree latency and/or the second clock tree latency, adjusting a skew between the second clock signal and the first clock signal, setting the cycle time of the first clock source to an operating cycle time.

Cycle accurate skew adjust

A method for adjusting a skew between a second clock signal and a first clock signal is provided. The second clock signal has been propagated from a first clock source through a second clock tree. The second clock tree comprises a programmable delay line that induces a delay. The method comprises at least one iteration of: measuring a skew between the second clock signal and the first clock signal, comparing an absolute difference of the measured skew and a sum of delay changes initiated in a time window preceding the measurement with a target skew, and initiating a delay change of the delay induced by the programmable delay line in the second clock tree depending on a result of the comparison.

Continuous skew adjust

Aspects of the invention include a process for receiving data and a first clock signal of a first chip and a second clock signal of a second chip, the data being received on a data path and the first clock signal being received on a clock signal path, and determining that the first clock signal is arriving before the second clock signal by a difference quantity. Also, the process includes adding delay to the data path and the clock signal path according to the difference quantity.

Early mode protection for chip-to-chip synchronous interfaces

Method and system for testing a memory array having a non-uniform binary address space. The test system includes a test engine for generating addresses for the memory array and for generating and applying data patterns to the memory array. The test engine has an address generator including a series combination of a linear register and a binary counter for generating the non-uniform address.

Non-binary address generation for ABIST

An array built-in, on-chip self test system for testing a memory array and a method of testing the memory array. The memory array has data input ports, data output ports, and address ports, and a data control subsystem, an address control subsystem, and a comparator. The data control subsystem generates and applies deterministic data patterns to the data input ports of the memory array. The address control subsystem generates addresses for application to the memory array in coordination with said data control subsystem, and includes a sequence counter, a count rate controller for the sequence controller, a count rate controller divider to control the number of cycles per address, an address controller to provide granular control of addresses, and an X-OR gate receiving an input from a sequence counter and from the address controller, the X-OR gate outputting an address bit to the memory array. The comparator compares the data inputted to the data input ports of the memory array from the data control subsystem with the data outputted from the data output ports of the memory array.

ABIST address generation

A cutting cylinder of a newspaper press assembly has a magnet member mounted thereon. A semiconductor Hall effect pickoff is mounted in proximity to the cutting cylinder such that the magnet passes by this sensor in close proximity thereto once during each rotation of the cylinder. The output of the Hall effect sensor, which is in the form of pulses, is fed both to a non-inverting and an inverting amplifier. The outputs of the amplifiers are fed to a differential detector which provides an output only in accordance with the difference between the inputs fed thereto, thus eliminating common-mode inputs such as noise signals. The output of the differential detector is fed to a digital counter which provides a count of the input pulses representing the number of newspapers or the like detected by the sensor. The output of the digital counter in turn is fed to a readout device which provides a suitable readout of this count which may be in the form of a display.

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Pleasant Valley, NY, United States of America

Douglas J Malone