Serial communication between matlab and arduino problem

i was trying to connect the arduino uno to matlab using this setupSerial.m file

if true
  %%~~~~~~~~~ SERIALPUSH SETUP ~~~~~~~~~ %
function [s,flag] = setupSerial(comPort)
% Initialize the serialpush port communication between Arduino and MATLAB
% The input value is the COMPORT should be changed as per requirement
% We ensure that the arduino is also communicatiing with MATLAB at this
% time. A predefined code on the arduino acknowledges this.
% if setup is complete then the value of setup is returned as 1 else 0
%instrfind
flag = 1;
s = serial(comPort);
set(s,'DataBits', 8 );
set(s,'StopBits', 1 );
set(s,'BaudRate', 9600);
set(s,'Parity', 'none');
fopen(s);
{
a='b';
while (a ~='a')
a=fread(s,1,'uchar');
end
if (a=='a')
disp('serial read');
end
fprintf(s,'%c','a');
mbox = msgbox('Serial Communication setup.'); uiwait(mbox);
}
disp(fscanf(s,'%s'));

end

so when i do this

>> comPort='com4'; [s,flag] = setupSerial(comPort);

I get this error

Error: File: setupSerial.m Line: 17 Column: 2 The expression to the left of the equals sign is not a valid target for an assignment.

the setup arduino code is

      if true
        void setup()
{      
  // Initialize the Serial Bus for printing data.
  Serial.begin(9600);
  Serial.println('a');
  char a = 'b' ;
  while(a != 'a')
  {
  a=Serial.read();
}

// Initialize the 'Wire' class for the I2C-bus.
Wire.begin();

// Clear the 'sleep' bit to start the sensor.
MPU9150_writeSensor(MPU9150_PWR_MGMT_1, 0);

MPU9150_setupCompass();
}

      end
Can anyone tell me what is the problem plz?

Answer 1

[Geoff Hayes]

Noorhan - try removing the braces, { }, around your code. There are unnecessary (and incorrect) for MATLAB programming which can lead to an error like the one that you are observing. For example, if I have the following simple function

 function g

 k = 1;
 while k<42;
 {
    t=3;
    k=k+1;
 }
 end

I see the same error, The expression to the left of the equals sign is not a valid target for an assignment., as you. Just remove the braces to get

 function g

 k = 1;
 while k<42;
    t=3;
    k=k+1;
 end

and you should be able to get further with your testing.