Hi @Samuel Park
I understand that you are working to create a serial link between MATLAB and your Arduino, but it seems that MATLAB isn't picking up the USB connection.
Firstly if you define a serial port object in MATLAB using a variable name that's already in use, MATLAB will try to initiate a connection to that port again.
This action can lead to errors if the port is still open. It's essential to disconnect and delete any prior serial port objects before you attempt to establish a new connection.
If you run the following code it will throw the error:
s=serialport("COM1",9600);
% reusing the object again
s=serialport("COM1",9600);
You can follows these step for the resolution:
- Arduino IDE Confirmation: Check that the Arduino is detected in the Arduino IDE and that its port is visible under "Tools" > "Port".
- Port Name Verification: Ensure that the port name you're using in MATLAB (`/dev/cu.usbmodem141201`) is identical to the one displayed in the Arduino IDE.
- Shut Down Competing Programs: Exit any other programs that might be engaging the serial port, like the Arduino IDE, to avoid interfering with MATLAB's access.
- Remove Existing Serialport objects: If you need to make a new serial connection but have an existing serial port object, it's important to remove that object first. To do this in MATLAB, you can use the commands:
delete(instrfind); % This removes any existing serial port objects
clear s; % This clears the 's' variable if it's been set before in your workspace
s = serialport("/dev/cu.usbmodem141201", 115200); % This creates a fresh serial port object
Refer to the following MathWorks Documentation for details regarding the 'serialport':
- https://www.mathworks.com/help/matlab/serial-port-devices.html
- https://www.mathworks.com/help/matlab/matlab_external/troubleshooting-serial-port-interface.html
Hope it helps
