Documentation

Create a class that subclasses from matlab.System.

Define one of the following sets of methods:

• setupImpl and stepImpl

• setupImpl, outputImpl, and updateImpl

  To use the outputImpl and updateImpl methods, your System object must also inherit from the matlab.system.mixin.Nondirect class.

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 step method, or the output and update methods.

Note:   The resetImpl method runs automatically during System object initialization. For HDL code generation, you cannot call the public reset method.

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 = step(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.