Data processing: measuring – calibrating – or testing – Testing system – Of circuit
Reexamination Certificate
1998-02-26
2001-03-20
Assouad, Patrick (Department: 2857)
Data processing: measuring, calibrating, or testing
Testing system
Of circuit
C717S152000, C716S030000
Reexamination Certificate
active
06205407
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates generally to automatic test equipment and more particularly to a system and method for efficiently generating a test program for use in automatic test equipment.
Digital integrated circuits, such as microprocessors and application specific integrated circuits (ASICs) require substantial testing to ensure high quality and performance with low defect levels. During electronic circuit design, the testing of these devices is generally performed by automatic test equipment (ATE) which performs the testing under the control of a test program. The data for the test program can originate from several sources including scan and pattern data extracted from a design simulation program or from scan based automatic test program generation (ATPG).
A variety of commercial companies offer test data generation programs, either ATPG programs or design simulation programs. Since there are a variety of test program formats, most test data generation programs output to the intermediate format of a waveform language (the intermediate waveform format) instead of to the many different test program formats. It then becomes the user's problem to find a method of translating the intermediate waveform format into the format required for the test program. Getting the data from the source form to the ATE requires complicated data manipulation and often, custom programming, all of which requires large amounts of time and disk space.
Existing methods use the intermediate waveform format for two reasons. First, an intermediate waveform format conventionally provides a common starting point for all translations to all ATE formats. Second, existing methods presume that the translator needs to make many passes over the source test data to create the format required for the ATE. Therefore, existing methods presume a need for an intermediate data structure, such as the intermediate waveform, that contains all the source test data.
Existing methods treat the process of generating a test program from source test data as a multi-step process: first generating the intermediate waveform and then translating. Often, the translating step has multiple sub-steps that also operate serially, requiring each sub-step to be completed prior to the next sub-step.
There are a number of disadvantages with this approach. First, this process is slow. It requires that the test data generation program first create the intermediate waveform format which is separately run through a translator. Each step in this process can take hours for a state-of-the-art integrated circuit. Second, the intermediate waveform format consumes a considerable amount of disk space. The size of these files can quickly fill up disk drives of modern computers. The intermediate waveform format is often thrown away after the translation, making this a wasteful and inconvenient step.
When going from the intermediate waveform format to the test program, current methods require using or writing a separate translator for every ATE format. Typically, this translator is written by a test engineer, though there are commercial programs available to translate from the intermediate waveform format to an test program. But existing translation methods require a different translation program for each ATE format and follow the known methodology of making multiple passes over an intermediate waveform format.
Existing programs are inflexible and do not allow for an automatic way to go from the source test data all the way to the test program in one process.
Therefore, there is a need for a flexible system and method for automatically generating a test program from source test data.
Further, there is a need to automatically translate source test data without writing a separate translator for every ATE format.
Additionally, it is desirable to be able to run a test data generation program, such as a Scan ATPG or a Simulation program, and concurrently translate the data into a test program, thereby saving large amounts of both time and disk space.
SUMMARY OF INVENTION
The invention provides a flexible and efficient system and method for generating a test program for use in automatic test equipment. According to the invention, this is accomplished by a software program (the translator program) which requires two inputs: a setup control file and a data stream of source test data.
The invention enables the user to specify a setup control file to define information to the translator in advance, such as the target ATE platform, the desired format of the test program and desired run time warnings. This definition is accomplished by use of a setup control mechanism, preferably a Graphical User Interface (GUI), that allows the user to select the target ATE (such as the IMS ATS and the Teradyne J971) as well as a variety of other characteristic information to customize the test program. The selection can also be done by any variety of user input methodologies, such as a conventional User Interface(UI) or by inputting a list of settings. Once the user has defined the system setup file, that file may be stored and reused or revised in future test program generations.
Second, a data stream of source test data is input into the translator program. This invention is flexible to accept source test data generated from a test data generation program, such as a scan ATPG or a simulation program, or from an existing test data file, generated previously. The invention is also flexible to allow different configurations of the testing system. For example, the ATPG program can run on the same processor or on a different processor than the translator program.
Preferably, the source test data is streamed serially into the translator as it is generated by the test data generation program. Alternately, the input is streamed serially from an existing test data file. Streaming the data in serially allows for a significant benefit of this invention: concurrent translation of the source test data into an ATE format while the source test data is being generated by the test data generation program. Under this scenario, the source test data is coming from a test data generation program, either a Scan ATPG program(such as View Logic, Mentor Graphics and Synopsis) or a capture from a design simulation program (such as Cadence Verilog XL). By running the test data generation program and streaming the data to the translator program to receive and process concurrently, there is no need for the large memory-consuming intermediate waveform format.
Further, if the test data generation program and the translation program run on separate microprocessors, there is the additional benefit of a large time savings of doing these tasks concurrently rather than one step at a time. The test program is generated in essentially the same amount of time as it takes the test data generation program to generate the source test data.
The inputting of source test data is different from the prior art in several ways. Prior art translators read a file containing the source test data in the waveform intermediate format. The translator has access to the entire file at all times and often makes several passes over the data. This invention takes data, either from a source test generation program or from an existing file, and marks the scan (serial) and pattern (parallel) data of the source test data. The only data that is important to the translator in this invention is the scan and pattern data. The other data conventionally found in the source test data, such as waveform and timing data, is ignored by the invention. The source test data, including the scan and pattern data, is streamed to the translator. The translator processes each unit of data only once, as it is streamed in. When using a source test generation program, this invention accomplishes this single-pass processing by utilizing function calls linked directly into the source test generation program. When using an existing test data file, this invention uses a parser program to stream the data as if it was being generated by a t
Geiger Susan P.
Testa Louis C.
Assouad Patrick
Integrated Measurement Systems, Inc.
Marger & Johnson & McCollom, P.C.
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