Two interrupt-executed functions write to the same variable

[isosphere]

Both readerdata0() and readerdata1() write to readerdata. I suspect this is a bad idea, as they are both executed by interrupts and there is a potential for collision.

I've experimented a little bit with doing it separately and then recombining the data, but didn't have much luck.

Despite my discomfort with this, it really does seem to work. I'm not sure that it's a problem.