Xilinx, Inc.

Mehul R Vashi

Stephen M Douglass

Ahmad R Ansari

Alex Scott Warshofsky

Nigel G Herron

Steven P Young

Kiran B Buch

Robert Yin

Jane W Sowards

David P Schultz

Weiguang Lu

Shidong Zhou

Andy H Gan

Karthy Rajasekharan

Jing Jing Chen

Qingqi Wang

Michael Tsivyan

Prasad L Sastry

Ying Fang

Huimou Juliana Li

First and second sensing circuits are coupled to first and second data lines, respectively, and sense levels of current leakage or a memory cell state on the first and second data lines. First and second keeper circuits are coupled to the first and second data lines, respectively, and drive the first and second data lines by a voltage supply through biased transistors. First and second leakage latches are coupled to receive and latch state of signals output from the first and second sensing circuits, respectively. A control circuit is coupled to the first leakage latch, second leakage latch, and outputs of the first and second sensing circuits. The control circuit is configured to select either the signal output from the first sensing circuit or the signal output from the second sensing circuit in response to states of the first and second leakage latches.

Current leakage management controller for reading from memory cells

A method of enabling variable latency data transfers in an electronic device, such as an FPGA with an embedded processor, is described. According to one aspect of the invention, a method comprises steps of providing an address for a data transfer between a memory controller and a peripheral device; coupling an address valid signal to the peripheral device; transferring the data between the memory controller and the peripheral device; and receiving a data transfer complete signal at the memory controller. According to another aspect of the invention, an integrated circuit enabling a variable latency data transfer is described. The integrated circuit comprises peripheral device; a memory controller coupled to the peripheral device; an address valid signal coupled from the memory controller to the peripheral device; and a transfer complete signal coupled from the peripheral device to the memory controller.

Method of and circuit for enabling variable latency data transfers

Interconnecting logic provides connectivity of an embedded fixed logic circuit, or circuits, with programmable logic fabric of a programmable gate array such that the fixed logic circuit functions as an extension of the programmable logic fabric. The interconnecting logic includes interconnecting tiles and may further include interfacing logic. The interconnecting tiles provide selective connectivity between inputs and/or outputs of the fixed logic circuit and interconnect of the programmable logic fabric. The interfacing logic, when included, provides logic circuitry that conditions data transfers between the fixed logic circuit and the programmable logic fabric. In one operation, the programmable logic fabric is configured prior to the startup/boot sequence of the fixed logic circuit. In another operation, the fixed logic circuit is started up and is employed to configure the programmable logic fabric.

Programmable gate array and embedded circuitry initialization and processing

The various embodiments of the present invention relate to circuit verification. According to one embodiment of the invention, a method of enabling timing verification of a circuit design comprises steps of generating a timing model of a processor core for a static timing analysis tool; coupling timing data related to the processor core to the static timing analysis tool; extracting resistance and capacitance data for interconnect circuits of the circuit design; coupling the resistance and capacitance data for the interconnect circuits to the static timing analysis tool; and verifying the performance of the circuit design using the static timing analysis tool. According to another embodiment of the invention, a system for enabling timing verification of a circuit design is described.

Method of enabling timing verification of a circuit design

Method and apparatus for generating a test program for an integrated circuit having an embedded processor. One embodiment has a system which includes an embedded microprocessor; a plurality of assembly language instructions stored in a memory, where the assembly language instructions substantially exercise a critical path or a path closest to the critical path in the embedded microprocessor; and programmable test circuitry having a programmable clock circuit for providing a multiplied clock signal to the embedded microprocessor in order to execute the assembly language instructions.

Testing of an integrated circuit having an embedded processor

According to one embodiment of the invention, a method of accessing instruction data from a memory comprises steps of specifying a predetermined address of a memory for storing instruction data; writing instruction data to the predetermined address in the memory; reading the instruction data from the predetermined address after the step of writing instruction data; and determining whether the instruction data is valid. According to another embodiment of the invention, a method describes a method of accessing instruction data from a memory by way of first and second data buses. According to a further embodiment, instruction data read back from the memory is multiplexed to a memory controller. A circuit for accessing instruction data written to a memory is also described.

Circuit for and method of accessing instruction data written to a memory

A method of verifying a circuit implementing a data transfer protocol is disclosed. According to one embodiment of the invention, the method comprises steps of providing a block under test that implements a variable latency data transfer protocol; coupling a verification circuit to the block under test; enabling variable latency data transfers to the block under test; and verifying that the block under test is implementing the variable latency data transfer protocol. The method could be implemented to verify the operation of a memory controller of an FPGA, for example. According to another embodiment, a method enabling a multi-stage verification is disclosed. Finally, specific implementations of a verification circuit coupled to an on-chip memory controller of an FPGA are disclosed.

Method of and circuit for verifying a data transfer protocol

Generation of consistent connection data for a first circuit embedded in a second circuit. In one approach, a master file is established with design data that includes for each pin in the embedded circuit, a hardware description language (HDL) pin name from an HDL description of the embedded circuit, a schematic pin name of the second circuit to which a corresponding pin in the embedded circuit is to connect, a signal direction associated with the pin, and a name of a clock to trigger a signal on the pin. A plurality of design views are generated from the master file. Each design view has a unique format relative to the other design views and includes for each pin in the embedded circuit design, at least the HDL pin name, the associated schematic pin name, and a signal direction associated with the pin.

Generation of design views having consistent input/output pin definitions

A bus arbiter controls the bus frequency in a system that includes a plurality of bus masters and a plurality of slaves. The bus frequency is determined according to the internal frequency of the devices that are part of the transaction. Additionally, the bus frequency is set according to the length of the bus between the devices that are a part of the transaction and, correspondingly, the expected amount of impedance there between. As a part of the present invention, a master seeking bus resources to initiate a transaction generates a bus request and a destination address to the bus arbiter so that it may determine a corresponding bus frequency in advance. Thereafter, the bus arbiter sets the bus frequency to a value that corresponds to the transaction that is about to take place thereon. Next, the bus arbiter issues a grant signal to enable the master to use the bus. Each slave device for a transaction then generates or receives sample cycle signals indicating when a signal should be read on the bus.

Method and apparatus for synchronized buses

During a reset condition or prior to system initialization of an FPGA-based system (), a FPGA () can be pre-configured by loading a value from a memory cell () into at least one flip-flop () of the FPGA, which represents a configuration register for an FPGA memory controller (). The FPGA memory controller can be configured using the value loaded in the flip-flop. The value loaded into the flip-flop from the memory cell can be a default value previously stored in the memory cell.

Method and system for controlling default values of flip-flops in PGA/ASIC-based designs

Interconnecting logic provides connectivity of an embedded fixed logic circuit, or circuits, with programmable logic fabric of a programmable gate array such that the fixed logic circuit functions as an extension of the programmable logic fabric. The interconnecting logic includes interconnecting tiles and may further include interfacing logic. The interconnecting tiles provide selective connectivity between inputs and/or outputs of the fixed logic circuit and the interconnects of the programmable logic fabric. The interfacing logic, when included, provides logic circuitry that conditions data transfers between the fixed logic circuit and the programmable logic fabric.

Programmable gate array having interconnecting logic to support embedded fixed logic circuitry

A data processing system having a user configurable memory controller, one or more local block RAMs, one or more global block RAMs and a processor core can be configured in a single field programmable gate array (FPGA). The address depth of the global block RAMs and the number of wait states can be selected by a user, and they can be set either prior to configuration of the FPGA or programmed using instructions of the processor core. The number of wait states of the local block RAM is also user selectable. An algorithm that can optimize the address depth and the number of wait states to achieve a performance level is also disclosed. The present invention can be applied to designs having separate instruction and data sides.

User configurable memory system having local and global memory blocks

A method and system for converting an architecture-specific design of a first type into an architecture-specific design of a second type such that race conditions and other anomalies are detected in the second type. By identifying routing delays in a first architecture and what those same routing delays would be in a second architecture, the method and system verify that a design has been properly converted. The method and system are applicable to the conversion of programmable interconnect logic devices to mask programmable logic devices. For example, a method for verifying timing for a design implemented in a new device when the design is to be moved from an old device. The method is particularly useful for verifying timing in a mask programmable device (HardWire) when the design is being converted from a field programmable device (FPGA). By identifying routing delays of critical paths and paths for which a designer has established requirements, the method efficiently and reliably determines which paths in the new device need to be compared and verified. Reports generated according to the method of the invention greatly simplify the task of assuring a satisfactory conversion.

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San Jose, CA, United States of America

Mehul R Vashi