Modeling S-R Flip flip for HDL code generation

Sir/Madam,

For the functional model I used S-R flip flop in simulink library. I realized that the model is incompatible with HDL code generation. The HDL work flow section 2.3 flags error message: incompatible with :..Combinatorial Logic' is not supported for HDL code generation. To continue with code generation, comment out this block..."

The error is specific to the combinatorial logic block used in the S-R flip flop model available in the simulink library.

Please point me to an appropriate answer record which implements HDL compatible S-R flip flop model.

Thank You

[Bharath Venkataraman]

Do you require the S-R flip flop or will the delay block that simulates the behavior of a register meet your needs?

[Nathan Ellis]

Use the unit delay enabled resettable synchronous block and join the u and E lines for the Set signal.

Answer 1

[Kiran Kintali]

Attached in an example model that works in 22a release.

[Gregory Chapelle]

Will this RS model work for the earlier version R2020b if you select "Save>Export Model to>Previous Version"? I would really like to use this too, so could you save this as an earlier version please?

[Kiran Kintali]

It should work in a previous release. You can try Simulink preferences and disable the check that prevents you loading the model in an older version.

https://www.mathworks.com/help/simulink/slref/simulinkpreferences.html;jsessionid=ada6a105de56a1ae5150cf9a4e8b

Do not load models created with a newer version of Simulink — Option to prevent models created in newer version of Simulink from loading

On (default) | Off

Specify whether to load a model last saved in a newer version of Simulink software.

• When this option is selected and you try to load a model last saved in a newer version of Simulink, the model does not load, and an error message appears in the MATLAB Command Window.
• When this option is cleared and you try to load a model last saved in a newer version of Simulink, the model loads, and a warning message appears in the MATLAB Command Window.

slprivate('showprefs')