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Ignore output data checking (number of samples)

Specify number of samples during which output data checking is suppressed

Model Configuration Pane: Test Bench


Specify number of samples during which output data checking is suppressed.


This option is disabled if you select the entire model. Select the DUT instead for Generate HDL for setting.


0 (default)

The value must be a nonnegative integer.

When the value of Ignore output data checking (number of samples), N, is greater than zero, the test bench suppresses output data checking for the first N output samples after the clock enable output (ce_out) is asserted.

When using pipelined block implementations, output data may be in an invalid state for some number of samples. To avoid spurious test bench errors, determine this number and set Ignore output data checking (number of samples) accordingly.

Be careful to specify N as a number of samples, not as a number of clock cycles. For a single-rate model, these are equivalent, but they are not equivalent for a multirate model.

You should use Ignore output data checking (number of samples) in cases where there is a state (register) initial condition in the HDL code that does not match the Simulink® state, including the following specific cases:

  • When you set the DistributedPipelining property to 'on' for the MATLAB Function block (see Use Distributed Pipelining Optimization in Models with MATLAB Function Blocks)

  • When you set the ResetType property to 'None' for the following blocks:

    • commcnvintrlv2/Convolutional Deinterleaver

    • commcnvintrlv2/Convolutional Interleaver

    • commcnvintrlv2/General Multiplexed Deinterleaver

    • commcnvintrlv2/General Multiplexed Interleaver

    • dspsigops/Delay

    • simulink/Additional Math & Discrete/Additional Discrete/Unit Delay Enabled

    • simulink/Commonly Used Blocks/Unit Delay

    • simulink/Discrete/Delay

    • simulink/Discrete/Memory

    • simulink/Discrete/Tapped Delay

    • simulink/User-Defined Functions/MATLAB Function

    • sflib/Chart

    • sflib/Truth Table

  • When generating a black box interface to existing manually written HDL code


To set this property, use hdlset_param or makehdltb. To view the property value, use hdlget_param.

For example, you can specify this parameter for the symmetric_fir subsystem inside the sfir_fixed model using either of these methods.

  • Pass the property as an argument to the makehdltb function.

    makehdltb('sfir_fixed/symmetric_fir', ... 
                'IgnoreDataChecking', 2)
  • When you use hdlset_param, you can set the parameter on the model and then generate HDL code using makehdltb.

    hdlset_param('sfir_fixed', 'IgnoreDataChecking', 2)

Recommended Settings

No recommendations.

Programmatic Use

Parameter: IgnoreDataChecking
Type: integer
Default: 0

Version History

Introduced in R2012a