ASCII string to serial port

what is the best way to send an ASCII string to serial port

Does it need to be sent one character at a time?

I am trying to write a code in Matlab similar to this off the shelf software package.

Answer 1

[Shuba Nandini]

Hello Raha,

It is my understanding that you want to know the best way for sending the ASCII String to serial port either by sending the whole string or by sending one character at a time.

The most effective approach for sending an ASCII string depends on factors such as the length of the string and the data rate of the serial port. If the ASCII string is short, then the best way is to send the entire string at once using “fwrite” or “fprintf”. This approach minimizes the number of write operations and reduces the overall time.

You can refer to the below example for sending the entire string:

% Open the serial port
k = serial('COM1');
fopen(k);

% Send the ASCII string to the serial port
str = 'Hello';
fprintf(k, '%s', str);

% Close the serial port
fclose(k);

If the ASCII string is long, sending it one character at a time using “fprintf" may be a better approach. This allows the receiving device to process the data in smaller chunks and can prevent buffer overflow errors.

You can refer to the below example for sending one character at a time:

% Open the serial port
k = serial('COM1');
fopen(k);

% Send one character at a time using fprintf
str= 'Hello’;
for i = 1: length(str)
    fprintf (k, '%c', str(i));
end

% Close the serial port
fclose(k);

Here, '%c ' is used as a format specifier to send one character at a time. If you are trying to send the hexadecimal data, use %x or %X format specifier.

To know more about the “fprintf” and “fwrite”command, please refer to the below links:

• Write data to binary file - MATLAB fwrite (mathworks.com)
• Write text to device - MATLAB fprintf (serial) (mathworks.com)

I hope this helps!

Regards,

Nandini