Invalid syntax error when inputting input arguments

I am attempting to get a redboard Arduino Uno to communicate with MATLAB. I have run into the following error when entering input arguments as shown:

function [time, data] = ReadRedBoardData_v2('/dev/cu.wchusbserialfa130', 10, 3000, 'EKG')
Error:Error: File:
ReadRedBoardData_v2.m Line:
1 Column: 45
Invalid expression. Check
for missing multiplication
operator, missing or
unbalanced delimiters, or
other syntax error. To
construct matrices, use
brackets instead of
parentheses.

Answer 1

[Steven Lord]

When defining a function you need to give the names of the variables that will contain the data with which the user will call your function.

function [time, data] = ReadRedBoardData_v2(location, x, y, z)

When calling a function you don't include the function keyword.

[time, data] = ReadRedBoardData_v2('/dev/cu.wchusbserialfa130', 10, 3000, 'EKG')

In this call to ReadRedBoardData_v2 (with the definition I gave above) the variable location will contain '/dev/cu.wchusbserialfa130', the variable x will contain 10, the variable y will contain 3000, and the variable z will contain 'EKG'.

[Scott hUDSON]

Thanks! Now it is telling me that my output arguments appear to be unused. Not sure what that means.

[Scott hUDSON]

Here is the full code for reference. It looks like the function is being defined and called all in the same script.

[Steven Lord]

If you have a function:

function y = timestwo(x)
q = 2*x;
end

and you call this:

z = timestwo(21)

the value of y inside timestwo will be returned and stored in the variable z. What value is that? Since timestwo never assigned a value to the variable y, MATLAB doesn't know what to return and so you'll receive an error. To fix the problem assign something to the output variable.

function y = timestwo(x)
y = 2*x;
end