International Business Machines Corporation

Kenneth A Mahler

Robert J Devins

David W Milton

Peter Dean LaFauci

Mark E Kautzman

Paul J Ferro

Robert Dov Herzl

Paul G Ferro

William E Mitchell

Verification of external interfaces of cores on system-on-chip (SOC) designs frequently entails the purchase of costly standardized software models to test the external interfaces. Typically, the standardized models provide more functionality than is needed. Instead of standardized models, test models may be developed and utilized, but this also incurs cost and delay. The present invention provides an efficient and economical alternative. A mirror interface, or copy of the external interface undergoing verification, is used with a standardized control mechanism to verify the external interface. Because all interface I/O connections can thereby be utilized, a cost-effective and highly reusable way of verifying such interfaces is provided.

Method and system for logic verification using mirror interface

The time, effort and expense required to develop verification software for testing and de-bugging system-on-chip (SOC) designs represents a considerable investment. According to the method of the present invention, a portion of such verification software may be re-used in an operating system (OS) (i.e., a system used for, e.g., general business, technical or scientific applications as opposed to software testing) to capitalize on the investment. The verification software includes low-level device drivers (LLDDs) which were coded for and paired with specific device designs ('cores') throughout the verification process, and were consequently also verified (i.e., de-bugged) in the process. Thus, the low-level device drivers represent reliable software with detailed knowledge of the corresponding devices. By developing a thin middle-level device driver layer of software to interface between a particular OS and the lower-level device drivers, the LLDDs can be re-used in an OS that uses devices that the LLDDs were designed for. This frees SOC customers from having to develop low-level software and instead allows them to concentrate on developing their particular applications, or 'value-added' software.

Method for re-using system-on-chip verification software in an operating system

A method for communicating with and controlling design logic modules (&ldquo;cores&rdquo;) external to a system-on-chip (SOC) design during verification of the design uses verification software to generate and apply test cases to stimulate components of an SOC design in simulation; the results are observed and used to de-bug the design. Typically, SOC designs interface with cores that are external to the design. Existing methods of including such external cores in a verification test of a SOC design typically entail having to create special test cases to control the external cores; such test cases typically do not communicate with test cases being applied internally to the SOC and therefore lack realism. An external memory-mapped test device (EMMTD) according to the present invention is coupled between a SOC design being tested in simulation, and cores external to the SOC design. Internal EMMTD logic provides for control and status monitoring of an external core coupled to an EMMTD bi-directional bus by enabling functions including driving data on the bus, reading the current state of data on the bus, and capturing positive and negative edge transitions on the bus. In one embodiment, a test case being executed by a simulator embedded processor in the SOC can communicate with and control elements external to the SOC, by using the EMMTD to perform such functions as initiating external core logic which drives test signals to an internal core, directly controlling an internal core via its external interface, or determining the status of an external core.

Simulator-independent system-on-chip verification methodology

A method for developing re-usable software for the efficient verification of system-on-chip (SOC) integrated circuit designs. The verification software is used to generate and apply test cases to stimulate components of a SOC design (&ldquo;cores&rdquo;) in simulation; the results are observed and used to de-bug the design. The software is hierarchical, implementing a partition between upper-level test application code which generates test cases and verifies results, and low-level device driver code which interfaces with a core being simulated, to apply the test case generated by the upper-level code on a hardware level of operations. Test application and supporting low-level device driver pairs are used and re-used to test their corresponding component cores throughout the SOC development process, by creating higher-level test control programs which control selected combinations of the already-developed test application and device driver programs to test combinations of SOC components. The method provides for the efficient verification of SOC designs and, consequently, a reduced time-to-market for SOC products, because as the verification software is developed and stored, it becomes possible to test increasingly complex core combinations by creating relatively few high-level test programs which re-use already-existing lower-level software. Ultimately, the task of verifying a complex SOC design may be simplified to developing a single chip-specific test program which selects from already-existing test application, device driver and test control programs to perform a realistic test of a chip-specific combination of cores.

Method of developing re-usable software for efficient verification of system-on-chip integrated circuit designs

A method for using verification software for testing a system-on-chip (SOC) design including an embedded processor. The verification software is used to generate and apply test cases to stimulate the SOC design in simulation; the results are observed and used to de-bug the design. Verification of a SOC design which includes an embedded processor is typically very slow. To provide for a speed-up mode of verification in such a case, in the method of the present invention, verification software is partitioned into higher-level control code and lower-level device driver code. The higher-level code performs such functions as decision-making, test initialization, test randomization, multi-tasking, and comparison of test results with expected results. The low-level code interfaces with a core being simulated, to apply the test case generated by the upper-level code on a hardware level of operations. The partitioning of the verification software as described above allows for a &ldquo;split-domain&rdquo; mode of verification in which only the low-level code is executed by a simulated processor model, while the rest of the code executes externally to the simulator. Because most of the verification software executes externally to the simulator while only the low-level code executes on the simulated processor, the overhead of performing the high-level functions is removed from the simulator. As a result, faster verification is enabled.

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Essex Junction, VT, United States of America

Kenneth A Mahler