User`s guide

Types of Model Coverage
15-5
indicating each interpolation. If the total number of breakpoints of an n-D Lookup Table
block exceeds 1,500,000, the software cannot record coverage for that block.
For an example of lookup table coverage data in a model coverage report, see “N-
Dimensional Lookup Table” on page 19-30.
Note: Configure lookup table coverage only at the start of a simulation. If you tune a
parameter that affects lookup table coverage at run time, the coverage settings for the
affected block are not updated.
Modified Condition/Decision Coverage (MCDC)
Modified condition/decision coverage analysis by the Simulink Verification and
Validation software extends the decision and condition coverage capabilities. It analyzes
blocks that output the logical combination of their inputs and Stateflow transitions to
determine the extent to which the test case tests the independence of logical block inputs
and transition conditions.
• A test case achieves full coverage for a block when a change in one input, independent
of any other inputs, causes a change in the block's output.
• A test case achieves full coverage for a Stateflow transition when there is at least one
time when a change in the condition triggers the transition for each condition.
If your model contains blocks that define expressions that have different types of logical
operators and more than 12 conditions, the software cannot record MCDC coverage.
Because the Simulink Verification and Validation MCDC coverage may not achieve full
decision or condition coverage, you can achieve 100% MCDC coverage without achieving
100% decision coverage.
Some Simulink objects support MCDC coverage, some objects support only condition
coverage, and some objects support only decision coverage. The table in “Model Objects
That Receive Coverage” lists which objects receive which types of model coverage. For
example, the Combinatorial Logic block can receive decision coverage and condition
coverage, but not MCDC coverage.
To achieve 100% MCDC coverage for your model, as defined by the DO-178C/DO-331
standard, in the Coverage Settings dialog box, collect coverage for all of the following
coverage metrics: