I don't know what sort of numbers mouseinfo returns, but mxpos and mypos are only ints. Have you checked the values of mxpos/mypos? Have you tried making them longs? You are also doing a fair amount of String class stuff. Have you looked at memory usage?
the interrupt code I am using is below:
lcdshow( "STOPPED !" , "EPO button" ); while (1); // stop lcdshow( "STOPPED !" , "bumper hit !" ); while (1==1); // stop lcdshow( "STOPPED !" , "motor timeout" ); while (1==1); // stop
Is there anything I can do to resolve this or is it back to the drawing board?
It will be a while before I know if this has fully resolved the problem, but so far, so good :-)
I have modified the sketch so that it turns the interrupt off and calls the procedure the interrupt uses manually during this routine, when it has finished using the mouse it turns the interrupt back on
What you mean is that you have not seen the problems that this causes manifested yet.