Ryan - I suspect the problem is because your while loop is is not interruptible and so any change that you make in the GUI (pressing a push button or moving the slider) does not get processed so long as the while loop condition is true. One way to get around this would be to put a pause in the loop body (for a fraction of a second) so that other events (like moving the slider) can be evaluated. This probably won't fix the problem since your global variables won't update within the loop. One way to get around this is to communicate directly with the GUI to get the direction and the sliderVal. In order to do this, you would need to set the set the GUI HandleVisibility property to on, and the Tag property to something unique like MyGui. Then your while loop body would look something like
k=1;
while k==1
hGui = findobj('Tag','MyGui');
if ~isempty(hGui)
handles = guidata(hGui);
sliderVal = get(handles.slider1, 'Value');
direction = '';
if isfield(handles,'direction') % check to ensure this field exists
direction = handles.direction;
end
fprintf(s, direction);
pwm = num2str(sliderVal);
fprintf(s, pwm) %send strings via the serial port
end
pause(0.01);
end
In the above, I use k instead of i since MATLAB uses this latter variable to represent the imaginary number. The only change to your GUI code would then be in the push button callbacks where you would need to update the handles structure with a direction field whenever a push button is pressed.
function AddOneTag_Callback(hObject, eventdata, handles)
handles.direction = 'cw';
guidata(hObject,handles);
function AddTwoTag_Callback(hObject, eventdata, handles)
handles.direction = 'ccw';
guidata(hObject,handles);
function AddThreeTag_Callback(hObject, eventdata, handles)
handles.direction = 'stop';
guidata(hObject,handles);
The above code is untested though should work and removes the need for the global variables. Though...do you really need a separate program (with the while loop)? Can't the GUI do the communication for you? Is it really necessary to send the same data across the port or can you just send the updates instead?
If you don't need to send the same direction and pwm value, then you could just do this whenever a change is made. So the push button and slider callbacks would then send the updated data. (This assumes that you have created and opened your serial port object in the OpeningFcn of your GUI, saving the object to the handles structure so that you can access it from your other callbacks.
And if you do need to send the data continually (even though there is no change), then consider using a timer that is created and started from within your GUI that periodically sends the direction and pwm data.
