International Business Machines Corporation

Norbert Schumacher

Gottfried Andreas Goldrian

Bernd Leppla

Helmut Kohler

Francois Abel

Ingemar Holm

Alan Frederic Benner

Alain R Blanc

Juergen Koehl

Michel Poret

Ronald Pete Luijten

Joerg H Walter

Mitch Gusat

Volker Urban

Gerhard Zilles

Mark Verhappen

Cyriel Johan Minkenberg

Thomas G Koehler

Gilles Gervais

Ronald Peter Luijten

Juergen Saalmueller

Markus Cebulla

Lothar Felten

Joerg Kayser

Michel Colmant

Walter Pietschmann

Peter Mannherz

Michael Colmant

Abel Francois

Andreas Eisenhoffer

Harald Fischer

Marcel Naggatz

According to one aspect of the present disclosure, a method and technique for identifying odd nets in a hierarchical electronic circuit design is disclosed. The method includes: receiving a very high-speed integrated circuit hardware description language (VHDL) model of an electronic circuit design; modifying an architecture section of VHDL code of each endpoint component of the VHDL model to connect each input/output (IO) of the endpoint component VHDL code to an instance of a snoop VHDL code; executing a simulation of the VHDL model through a plurality of clock cycles while driving a logical value by the snoop VHDL code and deriving simulation clashes detected by the snoop VHDL code for each IO of the endpoint components; and extracting an odd net topology for the VHDL model based on the simulation clashes derived from the simulation.

Retrieving odd net topology in hierarchical circuit designs

A method for simulating an operation of a digital circuit () is described. The method utilizes cycle simulation, wherein in a cycle based simulation model () of the digital circuit () components () of the digital circuit () are clocked synchronously every cycle () of a functional clock (Clk). According to the invention, real digital circuit (), i.e. chip or combinatorial logic (), timing information is included in the cycle simulation by inserting delay latches () into the cycle based simulation model () of the digital circuit (), wherein a non-functional clock (Sim clock) is used to clock the delay latches (), so that each delay latch () delays the propagation of a signal (I, J, K) by a cycle () of the non-functional clock (Sim clock).

Simulating an operation of a digital circuit

The present invention relates to a method for validating the correct logical function and timing behavior of a digital circuit design within a cycle-based verification environment. The method comprises the steps of providing a VHDL description of the digital circuit design, performing a logic synthesis, wherein the VHDL description is turned into a design implementation in terms of logic gates, and creating a netlist including the elements of the digital circuit design and the connections between said elements. The method comprises the further steps of providing a transformation script with at least one transparent storage element, wherein said transparent storage element represents a path delay within the digital circuit design, creating a new netlist with the at least one transparent storage elements, running a verification, and checking if the new netlist is clean from a logical and timing point of view.

Method for validating logical function and timing behavior of a digital circuit decision

A communication system which consists of several modules&#x2014;operating in parallel on segments of a packet&#x2014;to increase speed and handling capacity. One module acts as master, the others are slave modules controlled by control signals derived by the master module. It is important that in each module the data segment and the respective control signal of each packet are correctly synchronized, because in large systems the data paths carrying packet segments and the control signal paths may have substantially different delays. The invention provides for measurement of the propagation delay differences and for introducing a controlled delay in each slave module, so that data segments and control signals can be correctly correlated by delaying either the one or the other. Synchronization packets are transmitted besides normal data packets, for obtaining time stamps which are used to determine the delay difference.

Method and arrangement for local sychronization in master-slave distributed communication systems

The present invention relates to a buffered crossbar switch which provides a step of changing the size and/or number of queuing buffer entries to ensure optimum buffer memory usage independent of the size of data packets processed.

Buffered crossbar switch

For switching or transmitting data packets, one can provide communication systems which consist of several modules &#x2014;operating in parallel on segments of a packet &#x2014;to increase speed and handling capacity. One module acts as master, others are slave modules controlled by control signals derived by the master module. It is important to correctly synchronize in each module the data segment and the respective control signal of each packet, because in large systems the data paths carrying packet segments and the control signal paths may have substantially different delays. The invention provides for measurement of the propagation delay differences and for introducing a controlled delay in each slave module, so that data segments and control signals can be correctly correlated by delaying either the one or the other. Synchronization packets are transmitted besides normal data packets, for obtaining time stamps which are used to determine the delay difference.

Method and arrangement for local synchronization in master-slave distributed communication systems

A system for switching data packets through a multiple (m) input, multiple (n) output switching device providing switching having a fast one-cycle throughput. A respective switching device behaves like an output queued switch from a set of distributed output queues reading the incoming input control information from the plurality of input ports (IP) and compresses the information in a form which allows an easy association with a respective output port (OP) to which an individual input port is temporarily mapped.

Chip circuit for combined and data compressed FIFO arbitration for a non-blocking switch

A method and system for switching data packets through a multiple (m) input, multiple (n) output switching device providing a switching method having a fast one-cycle throughput. A respective switching device behaves like an output queued switch from a set of distributed output queues reading the incoming input control information from the plurality of input ports (IP) and compresses the information in a form which allows an easy association with a respective output port (OP) to which an individual input port is temporarily mapped.

Combined and data compressed FIFO based arbitration for a non-blocking switch

The present invention relates to a buffered crossbar switch and its method of operation which provides a step of changing the size and/or number of queuing buffer entries to ensure optimum buffer memory usage independent of the size of data packets processed.

Buffered crossbar switch and its method of operation

Apparatus and method of operating a crossbar switch () having a control logic, an output port scheduler (), n input ports (i, . . . , i) and m output ports (o, . . . , o), wherein information packets are routed from said n input ports to said m output ports, and wherein said output port scheduler () controls the sequence of packets output at said output ports (o, . . . , o). To ensure fairness regarding packet transfer/routing and the packet sequence, an input port number corresponding to the input port a new information packet is arriving at is stored in round-robin mode in a port number buffer (pnb). For output, said input port number is retrieved from said port number buffer (pnb) in round robin mode, too, and with this port number, address information regarding the packet is obtained from a control logic buffer of the crossbar switch ().

Method of operating a crossbar switch

The present invention relates to switching technology in computer networks and in particular to a method and system for switching information packets through a m input, n output device. According to the invention it is proposed to temporarily buffer said packets according to a new, self-explanatory, preferred a linear addressing scheme in which a respective buffer location of consecutive stream packets results from a respective self-explanatory, or linear, respectively, incrementation of a buffer pointer. Preferably, a matrix of FIFO storage elements () having an input and an output crossbar can be used for implementing input/output paralleling modes (ILP,OLP) and multiple lanes and achieving address input/output scaling up to a single cycle.

Control logic implementation for a non-blocking switch network

The invention proposes a switching arrangement for transporting data packets which comprise a data packet destination information and a payload, to one or more output ports. The switching device is able to route the arriving data packets according to the data packet destination information, to at least one dedicated of the output ports. It comprises at each input port an input buffer with at least as many single input queues as there are output ports, and an input controller for each input port, serving for controlling the order of multiplexing the data packets from the input queues of the corresponding input buffer to the switching device. The total of input ports is divided up into several subsets of input ports. Each subset in the switching device has its separate output buffer for storing at addresses therein at least the payload of each data packet arriving at the input port. At least one set of as many output queues as the switching arrangement has output ports are arranged. In these output queues at least the address of each payload stored in the output buffer is stored, sorted according to the data packet destination information. The stored payload is then deliverable to its dedicated at least one output port under use of the stored addresses.

Switching arrangement and method with separated output buffers

The present invention relates to a method and system for testing error detection programs dedicated for detecting hardware failures in a computer system, in which error case patterns comprising stimuli values are generated and response patterns to the hardware are evaluated. In order to develop and debug such error detection programs already at an early phase during hardware development it is proposed to feed a simulation model () of said hardware with said error patterns, and after running said model, evaluating () the model response patterns generated by the simulation model and comparing the response patterns with those expected as a result of the error detection program.

IML-stream generated error insertion / FRU isolation

The present invention relates to a method of operating a crossbar switch () having a control logic () and n input ports (i, . . . , i_n-) and m output ports (o, . . . , o_m-), wherein information packets of p different priority levels are routed from said n input ports (i, . . . , i_n-) to said m output ports (o, . . . , o_m-). Within said control logic (), a pool (CRA) of buffers (CRA, CRA, . . . ) is provided for each crosspoint () for temporarily storing address information related to said information packets.

The present invention relates to a method of operating a buffered crossbar switch. The proposed method reduces power dissipation in a buffered crossbar switch by reducing the number of crossbar buffer write processes.

Growing community of inventors

Neuhausen, Germany

Norbert Schumacher