Hello 희만 한,
It appears you're searching for the 'fcn' block within MATLAB's library browser, specifically in the R2021a release. Unfortunately, the 'fcn' block has been deprecated in some previous versions of MATLAB and is not present in R2021a.
As an alternative, you can utilize the 'MATLAB Function' block, which offers similar functionality.
For comprehensive guidance on how to use this block, please consult the MATLAB documentation on the 'MATLAB Function' block.https://www.mathworks.com/help/simulink/slref/matlabfunction.html
I hope it helps!
