MATLAB: Is there an option to never obey data type override on some blocks or signals in Simulink Fixed Point 6.2 (R2009b)

Question

I have a model and I use Simulink fixed-point tool to analyze it. The model contains blocks such as S-R Flip-Flops, FFT, etc that accept only signals of certain data type. When I analyze the model by setting the 'Datatype Override' option to 'True Doubles', I receive an error saying that these blocks are not compatible with 'true double' input. Is there a way by which I can selectively omit these blocks in the analysis?

Answer 1

This enhancement has been incorporated in Release 2010b (R2010b). For previous product releases, read below for any possible workarounds:

The ability to selectively omit certain blocks from data type override is not available in Simulink Fixed Point.

To work around this issue, partition the model into two subsystems:

1. One with blocks such as S-R flip flops etc

2. Another one with all the remaining blocks

3. Guard the first subsystems with 'Data Type Conversion' blocks so that output from second subsystem does not directly affect the blocks in the subsystem.

4. Set the Datatype override setting of the model to 'Use local settings' and then set the datatype override option for the individual subsystems to 'True Doubles'.