Create Callback for Comport in App designer?

Question

César Rodríguez Serrano 2022-3-3

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1662700-create-callback-for-comport-in-app-designer

回答： Abhijeet 2024-1-9

I am trying to create a callback everytime the comport writes "\n", but it does not work (the function is never called). This is the way I do it

function ConnectButtonPushed(app, event)
             app.s=serialport(app.COMportDropDown.Value, 115200);
             configureTerminator(app.s,"CR/LF");
             flush(app.s);
             configureCallback(app.s,"terminator",@readCOM);
             .
             .
             .

And this is the function that i try to call:

    
    methods (Access = private)
        function readCOM(~,src,~)
            data = readline(src);
            raw = strsplit(data,";");
            if(raw{0} == '#')
            rssi =   str2int(raw{1});
            ID =     str2int(raw{2});
            set(app.IDEditField, "Value", ID);
            signID = str2int(raw{3});
            set(app.SignEditField ,"Value", signID);
            RoadID = str2int(raw{4});
            set(app.RoadEditField ,"Value", RoadID);
            siteID = str2int(raw{5});
            set(app.SiteEditField ,"Value", siteID);
            orient = str2int(raw{6});
            set(app.OrientationGauge ,"Value", orient);
            end
        end
end

The function is never called, and I have tried every single step and it still does not work. Can somebody help me? Thank You in advance.

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Answer 1

Abhijeet 2024-1-9

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1662700-create-callback-for-comport-in-app-designer#answer_1386486

Hi César,

I understand that you have created a callback function which is not getting triggered.

You mentioned using "CR/LF" which corresponds to Carriage return and Line Feed. To make sure callback is gettting triggered verify that the device you are communicating with is actually sending these characters as terminators. Otherwise, the callback will not be triggered.

In the code you have provided , i suggest you to make the following changes in callback function :-

In MATLAB, array indexing starts at 1. So, 'raw{1}' is invalid and should be 'raw{1}' if you want to check the first element of the split data.
The function 'str2int' function does not exist in MATLAB. You should use 'str2double' or 'str2num' to convert string to number.

I hope this resolves the issue you were facing.