A system for physical emulation of electronic circuits or systems includes a data entry workstation where a user may input data representing the circuit or system configuration. This data is converted to a form suitable for programming an array of programmable gate elements provided with a richly interconnected architecture. Provision is made for externally connecting VLSI devices or other portions of a user's circuit or system. A network of internal probing interconnections is made available by utilization of unused circuit paths in the programmable gate arrays.

Apparatus for emulation of electronic hardware system

A hardware emulation system is disclosed which reduces hardware cost by time-multiplexing multiple design signals onto physical logic chip pins and printed circuit board. The reconfigurable logic system of the present invention comprises a plurality of reprogrammable logic devices, and a plurality of reprogrammable interconnect devices. The logic devices and interconnect devices are interconnected together such that multiple design signals share common I/O pins and circuit board traces. A logic analyzer for a hardware emulation system is also disclosed. The logic circuits necessary for executing logic analyzer functions is programmed into th e programmable resources in the logic chips of the emulation system.

Emulation system with time-multiplexed interconnect

The coverification system includes a reconfigurable computing system (hereinafter “RCC computing system”) and a reconfigurable computing hardware array (hereinafter “RCC hardware array”). In some embodiments, the target system and the external I/O devices are not necessary since they can be modeled in software. In other embodiments, the target system and the external I/O devices are actually coupled to the coverification system to obtain speed and use actual data, rather than simulated test bench data. The RCC computing system contains a CPU and memory for processing data for modeling the entire user design in software. The RCC computing system also contains clock logic (for clock edge detection and software clock generation), test bench processes for testing the user design, and device models for any I/O device that the user decides to model in software instead of using an actual physical I/O device. The user may decide to use actual I/O devices as well as modeled I/O devices in one debug session. The software clock is used as the external clock source for the target system and the external I/O devices to synchronize all data that is delivered between the coverification system and the external interface. The coverification system contains a control logic that provides traffic control between: (1) the RCC computing system and the RCC hardware array, and (2) the external interface (which are coupled to the target system and the external I/O devices) and the RCC hardware array. Because the RCC computing system has the model of the entire design in software, including that portion of the user design modeled in the RCC hardware array, the RCC computing system must also have access to all data that passes between the external interface and the RCC hardware array. The control logic ensures that the RCC computing system has access to these data. Pointers are used to latch data from the RCC computing system and the external interface to the internal nodes of the hardware model in the RCC hardware array. Pointers are also used to deliver data from the internal nodes of the hardware model to the RCC computing system and the external interface. Even if the data from the internal nodes of the hardware model is intended for the external interface, the RCC computing system must also be able to access this data as well.

Converification system and method

The SEmulation system provides four modes of operation: (1) Software Simulation, (2) Simulation via Hardware Acceleration, (3) In-Circuit Emulation (ICE), and (4) Post-Simulation Analysis. At a high level, the present invention may be embodied in each of the above four modes or various combinations of these modes. At the core of these modes is a software kernel which controls the overall operation of this system. The main control loop of the kernel executes the following steps: initialize system, evaluate active test-bench processes/components, evaluate clock components, detect clock edge, update registers and memories, propagate combinational components, advance simulation time, and continue the loop as long as active test-bench processes are present. Each mode or combination of modes provides the following main features or combinations of main features: (1) switching among modes, manually or automatically; (2) compilation process to generate software models and hardware models; (3) component type analysis for generating hardware models; (4) software clock set-up to avoid race conditions through, in one embodiment, gated clock logic analysis and gated data logic analysis; (5) software clock implementation through, in one embodiment, clock edge detection in the software model to trigger an enable signal in the hardware model, send signal from the primary clock to the clock input of the clock edge register in the hardware model via the gated clock logic, send a clock enable signal to the enable input of the hardware model's register, send data from the primary clock register to the hardware model's register via the gated data logic, and reset the clock edge register disabling the clock enable signal to the enable input of the hardware model's registers; (6) log selective data for debug sessions and post-simulation analysis; and (7) combinational logic regeneration.

Simulation/emulation system and method

This paper examines the achievements and future of system-on-a-chip (SoC) design methodology and design flow from the viewpoints of an in-house electronic design automation team of an application-specific integrated circuit and system vendor. We initially discuss the problems of the design productivity gap caused by the SoC's complexity and the timing closure caused by deep-submicrometer technology. To solve these two problems, we propose a C-based SoC design environment that features integrated high-level synthesis (HLS) and verification tools. A HLS system is introduced using various successful industrial design examples, and its advantages and drawbacks are discussed. We then look at the future directions of this system. The high-level verification environment consists of a mixed-level hardware/software co-simulator, formal and semi-formal verifiers, and test-bench generators. The verification tools are tightly integrated with the HLS system and take advantage of information from the synthesis system. Then, we discusses the possibility of incorporating physical design features into the C-based SoC design environment. Finally, we describe our global vision for an SoC architecture and SoC design methodology.

C-based SoC design flow and EDA tools: an ASIC and system vendor perspective

A hardware logic simulator includes a first memory, having memory locations respectively corresponding to a plurality of signals in a logic circuit to be simulated, for storing data representing states of the plurality of signals, and a second memory having memory locations respectively corresponding to those of the first memory and an address bus common therewith. When the content of a memory location at a given address of the first memory is changed during simulation, data representing the change in state of the corresponding signal is written in a second memory location corresponding to the given address. The content of the second memory is read out at the end of the simulation and the degree of completeness of the simulation is evaluated.

Hardware logic simulator

A logic simulator for simulating operation of a logic circuit is provided with gates divisible into successive levels according to a connection pattern between the gates. A pattern memory (16) memorizes the connection pattern as a bit sequence representative of direct connections between each gate of each level to the gates of a preceding level. A function memory (17) memorizes logic functions of the respective gates. Responsive to input logic states of each level, the bit sequence for the gates of the level under consideration, and the logic functions of the respective gates of that level, a calculator (25) calculates output logic states of that level as input logic states of a succeeding level successively for the gates of the level in question. For a higher speed of simulation, the logic circuitry may be divided into a predetermined number of gate groups, each consisting of gates of the successive levels. Each of the pattern and the function memories is divided into parts for the respective gate groups. In order to make the logic simulator have a further reduced memory capacity, the gates of each preceding level may be classified into gate blocks. A block specifier is additionally used. Under the circumstances, it is sufficient that each bit sequence should represent direct connections to the gate blocks. The calculator is supplied with the output logic states of each gate block.

Logic simulator using small capacity memories for storing logic states, connection patterns, and logic functions

A mixed level simulator, MIXS, is a logic verification tool which has multiple simulation capabilities. Main MIXS techniques are time wheel and selective trace algorithm for functional level simulation based on 'node' model concept and the linkage function of functional models, described in different detail, with network information. The mixed level simulation for large digital systems can be achieved very efficiently by using the above techniques.

MIXS: A Mixed Level Simulator for Large Digital System Logic Verification

This paper describes a mixed level hardware logic simulation system, called Hardware Logic Simulator II (HAL II). This paper first shows a HAL II simulation method. Then, it overviews HAL II hardware and software system configurations, simulation mechanism and estimates system performance. The HAL II system can handle a maximum of 5.8 million gates and a high level design language FDL (Functional Description Language). Finally, it discusses system applications and results. The paper also indicates that HAL II has been successfully used.

HAL II: A Mixed Level Hardware Logic Simulation System

Logic verification using automated test generation and simulation is described, in which functional design and structural design results are compared for functional equivalence. This new approach has been developed as a function of a mixed level simulator, MIXS1, and has strengthened MIXS top-down and bottom-up design support capabilities.

Nobuyoshi Nomizu

Papers

Hardware logic simulator

Logic simulator using small capacity memories for storing logic states, connection patterns, and logic functions

MIXS: A Mixed Level Simulator for Large Digital System Logic Verification

HAL II: A Mixed Level Hardware Logic Simulation System

Logic design verification using automated test generation