The top design unit selected for HDL code generation may not be inside a triggered subsystem.

Hi,

why was this limitation intoduced in Matlab?

In Matlab 2019, this limitation is not there. I wanted to port my model to Matlab 2020b, and run into this issue. Unfortunately I don't find anything in the documentation about this error message.

Can this limitation be circumvented with some settings?

Is this limitation also there in the latest versions of Matlab?

Answer 1

[Kiran Kintali]

The DUT targeted for code generation can be a whole model with root ports, or a regular virtual or atomic subystem, model reference block. Control subsystems such as triggered, enabled and resettable subsystems cannot be currently specificed as DUT. They need to be wrapped in one of the supported DUT configurations described above.

[Michael Felger]

@Kiran Kintali

Thank you, but this does not answer my question.

I understand that a triggered subsystem can not be the "DUT targeted for code generation".

Assume this topology:

• Simulink Model
• --> triggered subsystem
• --> ---> normal subsystem = DUT for HDL code generation

With R2020b, with a "normal subsystem" DUT which can be targeted for code generation, it is not possible to generate HDL code if this DUT is inside a triggered subsystem.

Which does not make sense for me at all, why does the HDL coder care about the triggered subsystem, which is above the DUT (and therefore not targeted for code generation at all)?

Also I can not find any documentation about this.

https://de.mathworks.com/help/simulink/slref/triggeredsubsystem.html

[Kiran Kintali]

Here is the page for the guidelines.

DUT Subsystem Guidelines

https://www.mathworks.com/help/hdlcoder/ug/dut-subsystem-considerations-and-guidelines-for-different-subsystem-types.html

The development team is working on relaxing this restriction in the upcoming releases.