Make the Stop button a toggle button.
Within the FOR loop, check the status of the Stop button. If it is toggled-on, then break out of the FOR loop.
After the FOR loop, toggle-off the Stop button.
[Please note that this is untested code]
for a = 1:loopCount
% << your main code >>
if app.tglStop.Value == 1
break
end
end % a
app.tglStop.Value = 0;
Hope this helps.
