Warning: Unsuccessful read: A timeout occurred before the Terminator was reached. 'serial' unable to read any data.

Hello!

I am trying to read data from Arduino Uno but i get this error "Warning: Unsuccessful read: A timeout occurred before the Terminator was reached. 'serial' unable to read any data."

Can any one help me please ?

Thank you in advance!

clear All
close All

COM  = serial('COM2','BaudRate',9600);%5,'Terminator','CR');
set(COM,'TimeOut',10)
fopen(COM);
interv = 240;
init_time = 1;
x =0;
while (init_time < interv)
 b = fscanf(COM) ;
 b = b(2:end-2);
 b = bin2dec(b);
 x = [x,b];
 plot(x);
 grid on ;
 init_time = init_time+1;
 drawnow;
end
fclose(COM);
delete(COM);
clear COM;

Answer 1

[Aghamarsh Varanasi]

Hi,

Did you try using 'serialport' function to create the serial connection, as 'serial' function is not recommended to use due to a few compatibility issues.

You can refer to this document to tranform your code to use 'serialport' function.

Also, as the issue seems to be with timeout, you can check with two changes:

1. Check if the input from Arduino actually has the Terminator 'CR'
2. Increasing the timeout period

[Walter Roberson]

The compatibility considerations link just come down to saying not to use fopen() and fclose() on serialport() objects. Nothing in that link indicates why serialport is better, faster, more flexible, fewer bugs, than serial(). Meanwhile there are things that serialport() cannot do that could be done with serial(). Such as fclose() a port without having to destroy the object and recreate it. (Think performance!!)

[su]

[su]

plz tell me what do I do

[Walter Roberson]

@su

https://knowledge.ni.com/KnowledgeArticleDetails?id=kA03q000000YGw9CAG&l=en-US shows how to use Process Explorer to determine which COM ports exist on your system, and how to figure out which process is already using the port.

Perrhaps your arduino is attached to a different port. Or perhaps some other process has it locked.