Matlab having problem interpreting streamed string into numbers.

Hello , i am sending 0x61 over and over which is the letter 'a' to matlab as shown bellow.

But when i want to convert the recieved letters into number and plot it gives me all NAN instead of 61 as shown bellow.

sObject=serial('COM4','BaudRate',115200,'TimeOut',10,'Terminator','LF')

Why do i get this NAN,i tried to plot and i get blank screen,why it cant convert my sent data into numbers?

Thanks.

function callbackSerial(ser,~)
global time;
val=fscanf(ser);
numval=str2double(val)
%numval=dec2bin(val);
time(16)=numval;
time(1)=[];
disp(time);
figure(1),plot(time);
end

[Rik]

What is the output you're getting from fscanf?

[fima v]

Hello Rik, i am getting char like behavior.

I dont want to mess arund with chars and ASCII

I have sent to matlab UINT8 data i just want to see it on matlab in HEX or binary.

Tis convertion to strings and chars is something i really dont what to see my data as

i want to send 0xF1 and to recieve on matlab the a variable which will hold 0xF1 or equivalent.

[Rik]

'char like behavior'

I was asking you about data type and size. If you already have a numeric value, you don't need str2double.

data=hex2dec('61');
disp(char(data))%cast to char only for display

a

disp(str2double(data))

   NaN

If you try to convert text to a number, but that text is not a number, you will get NaN.

[fima v]

Hello Rik, to your question i dont know how its recieved by matlabs i cant describe how i serially connect to MATLAB i use

val=fscanf(sObject);

To connect serial communication to matlab i use the following code.

In general i dont send character i send UINT8 data,specifically for our case

i send 0x61 ('a' value) and '\n' for LF terminator shown bellow.

how do i catch the HEX data

sObject=serial('COM4','BaudRate',115200,'TimeOut',10,'Terminator','LF')
sObject.BytesAvailableFcn={@callbackSerial};
fopen(sObject);

[Stephen Cobeldick]

See also related question:

https://www.mathworks.com/matlabcentral/answers/629973-coverting-string-to-ascii-value-in-matlab

Answer 1

[Steven Lord]

Please remove the semicolon from the end of this line, let your callback trigger a few times, and show us exactly what gets displayed in the Command Window.

val=fscanf(ser);

That information will likely help us determine how to "interpret" the data you're receiving from the serial port.

I suspect what you want is hex2dec not str2double, but the information about what exactly val is will support or refute that suspicion.

[fima v]

Hello steven, i have written again and added the data you asked in the link shown bellow

could you answer it?

https://www.mathworks.com/matlabcentral/answers/630864-serial-communication-shows-huge-batch-istead-of-steady-small-bursts?s_tid=srchtitle