Create a class that subclasses from matlab.System.

Define one of the following sets of methods:

Optionally, if your System object has private state properties, define the resetImpl method to initialize them to zero.

Write a top-level design function that creates an instance of your System object and calls the object, or calls the output and update methods.

Write a test bench function that exercises the top-level design function.

Generate HDL code.

In a writable folder, create a System object, CounterSysObj, which subclasses from matlab.System. Save the code as CounterSysObj.m.

classdef CounterSysObj < matlab.System

    properties (Nontunable)
        Threshold = int32(1)
    end
    properties (Access=private)
        State
        Count
    end
    methods
        function obj = CounterSysObj(varargin)
            setProperties(obj,nargin,varargin{:});
        end
    end
    
    methods (Access=protected)
        function setupImpl(obj, ~)
            % Initialize states
            obj.Count = int32(0);
            obj.State = int32(0);
        end
        function y = stepImpl(obj, u)
            if obj.Threshold > u(1)
                obj.Count(:) = obj.Count + int32(1); % Increment count
            end
            y = obj.State;          % Delay output
            obj.State = obj.Count;  % Put new value in state
        end
    end
end

Write a function that uses this System object and save it as myDesign.m. This function is your DUT.

function y = myDesign(u)

persistent obj
if isempty(obj)
    obj = CounterSysObj('Threshold',5);
end

y = obj(u);

end

Write a test bench that calls the DUT function and save it as myDesign_tb.m.

clear myDesign
for ii=1:10
    y = myDesign(int32(ii));
end

Generate HDL code for the DUT function as you would for any other MATLAB^® code, but skip fixed-point conversion.