System for testing digital components

A digital module comprising:

• a plurality of functional elements, at least one of which is assigned to a test unit having inputs and outputs;
• a test-pattern output register for applying a test pattern to the inputs of the test unit;
• and
• a self-test unit for controlling the test-pattern output register and loading the test-pattern output register with at least one test pattern that is a digital value, wherein the self-test unit is configured to generate the test pattern as a periodic sequence of a sub-pattern, a maximum periodicity of the test pattern being determined as a function of at least one active number of inputs of the test unit for a particular output of the test unit, the at least one active number being the number of inputs of the test unit where, and only where, changes to the inputs affect the particular output of the test unit.

A digital module comprising:

• a plurality of functional units that are assigned to at least one test unit having inputs and outputs;
• at least one test-pattern output register having a parallel output for applying a test pattern to the inputs of the at least one test unit;
• at least one evaluation unit for evaluating a test-pattern response applied to the outputs of the at least one test unit;
• and
• a self-test unit for controlling the at least one test-pattern output register and the evaluation unit and loading the test-pattern output register with the test pattern that is a binary value, wherein
• the self-test unit is configured to generate the test pattern as a sequence of at least one sub-pattern that is selected from a list of sub-patterns, the test pattern output register is a shift register that can be loaded serially with the test pattern and the evaluation unit evaluates the test pattern response at each cycle with which a new part of the test pattern is loaded into the test-pattern output register, the maximum length of the sub-pattern being a function of at least one active number of inputs of the test unit where, and only where, changes affect the particular output of the test unit.

A method for testing a digital module comprising the steps of:

• assigning functional elements of the digital module to at least one test unit, the test unit having inputs and outputs;
• controlling at least one test-pattern output register with a self-test unit;
• loading the at least one test-pattern output register with a test pattern;
• applying the test pattern in parallel to the inputs of the at least one test unit from the at least one test-pattern output register;
• and
• evaluating a response behavior of the at least one test unit to the test pattern by determining a maximum periodicity of the test pattern as a function of at least one active number of inputs for the test unit that correspond to a particular output of the test unit, the active number being a number of inputs of the test unit where, and only where, changes affect the particular output of the test unit.

A method for testing a digital module comprising the steps of:

• generating a test pattern, in the form of a digital value, as a sequence of at least one sub-pattern that is selected from a list of sub-patterns;
• loading at least one test-pattern output register serially with the test pattern, each test-pattern output register being a shift register and having a parallel output;
• applying the test pattern to inputs of at least one test unit having both inputs and outputs, the at least one test unit being associated with functional elements of the digital module;
• evaluating in a test cycle a test pattern response applied to the outputs of the at least one test unit with which a bit of the test pattern is loaded into the test-pattern output register, wherein the maximum length of the sub-pattern being a function of at least one active number of inputs of the test unit for a particular output of the test unit, the active number being the number of inputs of the test unit where, and only where, changes affect the particular output of the test unit.

A device for testing digital modules comprising:

• a test unit with inputs and outputs, the test unit being assigned to functional elements of the digital module;
• a test-pattern output register having a parallel output for applying a test pattern to the inputs of the test unit;
• a read or evaluation unit for respectively reading or evaluating a test pattern response that is applied to the outputs of the test unit;
• a self-test unit that controls the test-pattern output register and the evaluation or read unit and the loading of the test-pattern register with at least one test pattern in digital form;
• a data processing instrument for generating test data;
• and
• a test pattern transfer unit for transferring test patterns into the digital module for loading into the test-pattern output register, wherein
• the test pattern is a sequence of at least one sub-pattern that is selected from a list of sub-patterns or is a periodic sequence of a sub-pattern, the sub-pattern being in the form of a digital value, and the data processing instrument generates at least one sub-pattern of the test-pattern data and transfers the test-pattern data to the test-pattern transfer unit, where the test-pattern transfer unit generates the test pattern for loading into the digital module from the at least one sub-pattern received from the data-processing instrument, and a maximum periodicity of the test-pattern or a maximum length of the sub-pattern being determined as a function of at least one active number of inputs of the test unit for a particular output of the test unit, the active number being a number of inputs of the test unit where, and only where, changes affect the particular output of the test unit.