Altera Corporation

North American Philips Corporation

Altera Coporation

Chiakang Sung

Joseph Huang

Bonnie I Wang

Khai Nguyen

Yan Chong

Xiaobao Wang

Philip Pan

In Whan Kim

Richard G Cliff

Tzung-Chin Chang

Wayne Yeung

Gopinath Rangan

Gopi Rangan

Michael H M Chu

Bruce B Pedersen

Kerry S Veenstra

Francis B Heile

Pradeep Nagarajan

David Wolk Mendel

Srinivas T Reddy

Wanli Chang

Cameron R McClintock

Henry Kim

John Henry Bui

Sean Shau-Tu Lu

Jeffrey Tyhach

Andy Louie Lee

Christopher F Lane

Brian D Johnson

Sanjay K Charagulla

Robert R N Bielby

Phillip Pan

Fung Fung Lee

Jonathan Chung

Johnson Tan

Thomas Henry White

L Todd Cope

Ninh D Ngo

Jeffrey Erik Schulz

Adam J Wright

Philip Clarke

Rina Raman

Andreas Papaliolios

Andrew J Bellis

Peter Boyle

Ket Chiew Sia

Richard Shaw Terrill

Eric Choong-Yin Chang

Surgey Y Shumarayev

Myron Wai Wong

Bahram Ahanin

William W Leong

James A Watson

Nitin Prasad

Giles V Powell

Warren Nordyke

Wilma Waiman Shiao

Manoj B Roge

Edward Aung

Robert Richard Noel Bielby

Lay Hock Khoo

Ravish Kapasi

Xiabao Wang

Bonnie L Wang

Tony K Ngai

Hong Shi

Boon Jin Ang

Cheng-Hsiung Huang

John C Costello

Chih-Ching Shih

Dirk Alan Reese

Ali H Burney

Zhe Li

Stephanie T Tran

Guu Lin

Cheng H Huang

Robert R Bielby

Caroline Ssu-Min Chen

Ching-Chi Chang

Foong Tek Chan

Bruce B Pendersen

Im Whan Kim

Khai Huang

By Louis Leong, Legal Representative

William Leong, Deceased

Ronald L Cline

A buffer circuit with an adjustable reference voltage is presented. The buffer circuit with adjustable reference voltage has an input buffer circuit that is connected to a data input and a reference voltage. The output of the input buffer circuit is connected an eye monitor circuit that generates a transition signal based on a number of transitions of an output of the input buffer circuit. The output from the eye monitor circuit is that processed by a calibration control circuit that transmits a selection signal to a multiplexer. The multiplexer selects a level of the reference voltage based on the selection signal from the calibration control circuit.

On-die input reference voltage with self-calibrating duty cycle correction

An IC that includes a first memory controller, a second memory controller, and a first bonding circuit coupled to the first memory controller, where the first bonding circuit is a hard logic bonding circuit and is operable to coordinate memory control functions of the first memory controller and the second memory controller. In one implementation, the first memory controller is an N bits wide memory controller, the second memory controller is an M bits wide memory controller, and the first bonding circuit is operable to coordinate the memory control functions of the first memory controller and the second memory controller such that the first and second memory controllers together function as an N+M bits wide memory controller, where N and M are positive integers.

Integrated circuit with bonding circuits for bonding memory controllers

To achieve an even distribution of different types of connections, sets of connection cells have been devised having different ratios of signal, power and ground connections in which the signal connections are all within a maximum distance of a power and/or a ground connection. In addition, the shapes of the cells are such that the cells fit together in a repeatable array that fully covers the plane of the interface, i.e., an array that tiles the plane. Accordingly, to distribute the connections substantially uniformly across the interface, the ratio of the number of signal connections, power connections and ground connections is determined; a cell is selected from the set of cells that has approximately the same ratio of the number of signal connections, power connections and ground connections; and the selected cell is repeatedly used to allocate the signal, power and ground connections in accordance with the distribution of connections in the selected cell until all the connections are distributed.

Distribution of return paths for improved impedance control and reduced crosstalk

Methods and apparatus for providing either high-speed, or lower-speed, flexible inputs and outputs. An input and output structure having a high-speed input, a high-speed output, a low or moderate speed input, and an low or moderate speed output is provided. One of the input and output circuits are selected and the others are deselected. The high-speed input and output circuits are comparatively simple, in one example having only a clear signal for a control line input, and are able to interface to lower speed circuitry inside the core of an integrated circuit. The low or moderate speed input and output circuits are more flexible, for example, having preset, enable, and clear as control line inputs, and are able to support JTAG boundary testing. These parallel high and lower speed circuits are user selectable such that the input output structure is optimized between speed and functionality depending on the requirements of the application.

Programmable high-speed I/O interface

A programmable integrated circuit may have a memory controller that interfaces between master modules and system memory. The memory controller may receive memory access requests from the masters via ports that have associated priority values and fulfill the memory access requests by configuring system memory to respond to the memory access requests. To dynamically modify the associated priority values while the memory controller receives and fulfills the memory access requests, a priority value update module may be provided that dynamically updates priority values for the memory controller ports. The priority value update module may provide the updated priority values with update registers that are updated based on an update signal and a system clock. The priority values may be provided by shift registers, memory mapped registers, or provided by masters along with each memory access request.

Memory controllers with dynamic port priority assignment capabilities

A high speed IO buffer is disclosed. The high speed IO buffer includes a first P-type metal oxide semiconductor (PMOS) transistor coupled to an IO voltage source. The high speed IO buffer also includes a first N-type metal oxide semiconductor (NMOS) transistor coupled to a ground source, a second PMOS transistor coupled to the first PMOS transistor and a pad and a second NMOS transistor coupled to the first NMOS transistor and the pad. The first PMOS transistor, the first NMOS transistor, the second PMOS transistor and the second NMOS transistor are arranged in a cascoded arrangement.

High speed IO buffer

Method and circuitry for implementing high speed multiple-data-rate interface architectures for programmable logic devices. The invention partitions I/O pins and their corresponding registers into independent multiple-data rate I/O modules each having at least one pin dedicated to the strobe signal DQS and others to DQ data signals. The modular architecture facilitates pin migration from one generation of PLDs to the next larger generation.

Multiple data rate interface architecture

Systems and methods are disclosed for calibrating a Data Strobe (DQS) enable/disable signal and for tracking the timing of the DQS enable/disable signal with respect to changes in voltage and temperature (VT) in order to improve the timing margin of the DQS enable/disable signal in programmable devices using Double Data Rate (DDR) memory. In an exemplary embodiment, the system includes a gating circuit, a sampling circuit, and a delay chain tracking circuit. The gating circuit receives a DQS enable signal and a input DQS signal, calibrates the DQS enable signal based on an amount of delay, and outputs the calibrated DQS signal. The sampling circuit provides the amount of delay to the gating circuit based on a sampling clock. The delay chain tracking circuit maintains the timing of the calibrated DQS enable signal over a plurality of clock cycles based on the sampling clock and a leveling clock.

Circuit design technique for DQS enable/disable calibration

An integrated circuit may include a memory controller that interfaces with memory via one or more ports. A given port may be coupled to a comparator that receives data signals from the memory and a reference voltage signal and produces a corresponding output signal that identifies whether the data signals are logic one signals or logic zero signals. The memory controller may include detection circuitry coupled to the port that produces a target reference voltage signal for calibration of the reference voltage signal. The memory controller may include circuitry that produces the reference voltage signal based on control signals received from control circuitry. The control circuitry may generate the control signals to calibrate the reference voltage signal based on the target reference voltage.

Systems and methods for memory controller reference voltage calibration

An integrated circuit in a multi-chip package is provided. The integrated circuit may include adjustable interface circuitry configured to interface with other off-chip components. In particular, the adjustable interface circuitry may include a microbump input-output buffer operable to drive signals off of the integrated circuit and operable to receive signals from other integrated circuits in the multi-chip package via a microbump. The microbump input-output buffer may include output buffers and input buffers. The output buffers may have programmable drive strengths and may each be selectively switched in and out of use depending on the desired application. Each output buffer may include a level shifter, a buffer circuit, and multiple inverter-like circuits each of which can be turned on or off to adjust the drive strength of that output buffer.

Adjustable drive strength input-output buffer circuitry

Integrated circuits with clock generation and distribution circuitry are provided. Integrated circuits may include phase-locked loops configured to generate multiple clock signals that are delayed versions of one another. The clocks signal may be distributed to various regions on an integrated circuit using serially connected clock buffer blocks. Each buffer block may include bidirectional pairs of buffer circuits coupled in parallel. Each buffer circuit may have a first input configured to receive an input clock signal, an output at which a corrected version of the input clock signal is provided (e.g., an output at which an output clock signal with desired duty cycle is provided), a second input that receives a first delayed clock signal for setting the desired duty cycle for the output clock signal, and a third input that receives a second delayed clock signal that is high at least when the first delayed clock signal rises high.

Duty cycle distortion correction circuitry

An integrated circuit may include a memory controller serving as an interface between master processing modules and system memory. The master processing modules may provide memory access requests to the memory controller along with respective tag identifications. The memory controller may place the memory access requests in a queue for fulfillment. The memory controller may include a merging module that generates a memory access request to replace two or more memory access requests previously received from the master processing modules. The merging module may store information associated with the memory access requests that were merged and use the stored information to assign appropriate tag identifications to portions of data obtained from system memory when fulfilling the generated memory access request. The memory controller may include a verification module that can be used with test equipment to optimize the design of the master processing modules for improved memory access performance.

Systems and methods for providing memory controllers with memory access request merging capabilities

An integrated circuit may include memory interface circuitry that is used to communicate with off-chip memory. The memory interface circuitry may include data strobe (DQS) enable circuitry that receives DQS signals from the off-chip memory and that outputs a gated version of the DQS signals. The DQS enable circuitry may include an input buffer, a comparator, a latch, a flip-flop, a counter, and a gating circuit. The input buffer may receive an incoming DQS signal. The comparator may be used to determine when the incoming DQS signal starts to toggle. The latch may be used to control when a gating signal is asserted. The flip-flop controls the counter, which limits the duration that the gating signal is asserted. The gating circuit receives the DQS signal from the buffer and the gating signal and passes the DQS signal through to its output only when the gating signal is asserted.

Data strobe enable circuitry

Circuits, methods, and apparatus for dynamic control of source and termination impedances. One output stage provides a series termination when transmitting and a parallel termination when receiving data. A pull-up device has a nominal impedance of 50 ohms when the output stage pulls a pin from a low voltage to a high voltage, while a pull-down device has a nominal impedance of 50 ohms when the pin is pulled from a high voltage to a low voltage. Both the pull-up and pull-down devices are turned on when receiving data. Due to their non-linear current-voltage characteristics, the pull-up device appears as 50 ohms when the pin voltage is higher than one half the supply voltage, while the pull-down device appears as 50 ohms when the pin voltage is lower than one half the supply voltage. The pull-up and pull-down devices can be calibrated to provide a nominal 50 ohm impedance.

Dynamic termination-impedance control for bidirectional I/O pins

Growing community of inventors

Milpitas, CA, United States of America

Chiakang Sung