Sending four byte commands To serial port

Whilst I am familiar using the Serialport objects in Matlab with text, Im not sure to how to use the protocol "four byte commands". I've spend a bit of time searching but didn't find any examples applicable to the "new" serialport object in the latest versions of Matlab.

In particular, what syntax would I use to send the command (in bold):

Command: 8112 0000

And then read the response (in bold) and extract the numerical value of yy

Response: 5512 00yy

Thanks for any pointers

[Walter Roberson]

are those hex values or decimal?

[Jason]

Thats the issue, I dont know

Answer 1

[Walter Roberson]

cmd = [0x81 0x12 0x00 0x00];
write(YourPortObject, cmd, 'uint8');

response = read(YourSerialPortObject, 4, 'uint8');
if isequal(response, [0x55 0x12 0x00])
   yy = response(4);
else
   fprintf('unexpected response, got: %s\n', mat2str(yy));
end

[Jason]

Thamkyou Walter