multithreading - 如何连续从Matlab的串口读取？

Question

这是我的代码:

serialPort = 'COM3';
s = serial(serialPort,'BaudRate',9600);    
if (s.Status == 'closed')       
    s.BytesAvailableFcnMode = 'byte';
    s.BytesAvailableFcnCount = 200;
    s.BytesAvailableFcn = @Serial_OnDataReceived;

    fopen(s);
end

这是回调函数

function Serial_OnDataReceived(obj,event)
global s;
global i;
global endCheck;
global yVals;
global xVals;

if (s.Status == 'open')
    while s.BytesAvailable > 0 && endCheck ~= '1',
        data = str2num(fgetl(s));
        dlmwrite ('SensorsReading.csv', data, '-append');

        yVals = circshift(yVals,-1);
        yVals(end) = data(3);

        xVals = circshift(xVals,-1);
        i = i + 0.0125;
        xVals(end) = i;
    end

    figure(1);
    plot(xVals,yVals);

end    

结尾

在 FOPEN函数之后，我得到以下警告:

The BytesAvailableFcn is being disabled. To enable the callback property either connect to the hardware with FOPEN or set the BytesAvailableFcn property.

回调函数 Serial_OnDataReceived中发生的逻辑是否在其他线程上运行？

有没有办法将参数传递给函数？我想通过不同文件中的回调函数来修改主脚本中的数组。最好的方法是什么？
我还尝试在更新值以显示某种动态动画时绘制这些值。

Answer 1

我不知道是什么产生了警告，但是要回答您的其他问题(如何将参数传递给回调以及如何更新绘图)，更好的方法是在回调之外准备您的绘图，然后将句柄传递给回调仅用于更新。

nPointsInFigure = 10 ;  %// number of "sliding points" in your figure
step = 0.0125 ;         %// X points spacing
xVals = linspace(-(nPointsInFigure-1)*step,0,nPointsInFigure) ; %// prepare empty data for the plot
yVals = NaN(nPointsInFigure,1) ;

figure(1) ;
hp = plot( xVals , yVals ) ; %// Generate the plot (with empty data) it will be passed to the callback.

serialPort = 'COM3';
s = serial(serialPort,'BaudRate',9600);  
if (s.Status == 'closed')       
    s.BytesAvailableFcnMode = 'byte';
    s.BytesAvailableFcnCount = 200;
    s.BytesAvailableFcn = {@Serial_OnDataReceived,hp,step} ; %// note how the parameters are passed to the callback 
    fopen(s);
end

您的回调将变为:

function Serial_OnDataReceived(obj,event,hp,step)

global endCheck; %// I don't know how you use that so I could not get rid of it.

xVals = get(hp,'XData') ; %// retrieve the X values from the plot
yVals = get(hp,'YData') ; %// retrieve the Y values from the plot

while obj.BytesAvailable > 0 && endCheck ~= '1',
    data = str2num(fgetl(s));
    dlmwrite ('SensorsReading.csv', data, '-append');

    yVals = circshift(yVals,-1);
    yVals(end) = data(3);

    xVals = circshift(xVals,-1);
    xVals(end) = xVals(end-1) + step ;
end

set( hp , 'XData',xVals , 'YData',yVals ) ; %// update the plot with the new values

另请注意:(1)您无需在回调函数中检查串行端口的打开/关闭状态。如果事件被触发，则表示该端口已打开。 (2)您不需要将 s声明为全局变量， obj参数实际上是串行对象本身。