Serial Communication Code Error

I am attempting to communicate with a stepper motor using Serial communcation. I am currently getting an error using the fopen command saying that the first input must be a file name or file identifier or a file name, which I am pretty sure it is. Screenshots of the code and error are attached - please let me know what I am doing wrong.

Answer 1

[Chetan]

Hello @Ellen Boster,

I understand that there's an issue with the `fopen` command in your MATLAB code. It seems that MATLAB is expecting a file or a file identifier, but it's receiving something else. Without seeing the exact code snippet, I'll provide a general solution based on common issues with serial communication in MATLAB.

As of MATLAB R2020b, MathWorks recommends using the `serialport` object instead of the previously used `serial` object for serial communication. If you're using an older version of MATLAB or the `serial` object, you might encounter issues with commands like `fopen`.

Here's a basic outline of how to use the `serialport` interface for communicating with a serial device such as a stepper motor:

1. Create a `serialport` object with the appropriate COM port and baud rate.
2. Configure the serial port settings, if necessary (parity, stop bits, etc.).
3. Write data to the serial port using the `write` or `writeline` functions.
4. Read data from the serial port using the `read` or `readline` functions.
5. Close the serial port when communication is complete.

Here's a simple example of how the code might look:

% Define serial port and baud rate
comPort = 'COM3'; % Replace with the actual COM port
baudRate = 9600; % Replace with the baud rate for the stepper motor

% Create a serialport object
stepperSerial = serialport(comPort, baudRate);

% Configure serial port settings (if needed)
% configureTerminator(stepperSerial, "CR/LF");
% set(stepperSerial, 'Parity', 'none');
% ... other configurations ...

% Write a command to the stepper motor
writeline(stepperSerial, 'Your Stepper Motor Command Here');

% Read response from stepper motor (if expected)
response = readline(stepperSerial);

% Close the serial port when done
clear stepperSerial;

For more information on transitioning to the `serialport` interface, you can refer to the following MathWorks documentation:

https://www.mathworks.com/help/matlab/import_export/transition-your-code-to-serialport-interface.html

I hope this helps you resolve the issue with the serial communication code.

Thanks,

Chetan Verma