Bare metal code and a photodiode will both have latencies so low as to be irrelevant compared to everything else floating at dozens of milliseconds. EDIT: well

Bare metal code and a photodiode will both have latencies so low as to be irrelevant compared to everything else floating at dozens of milliseconds. EDIT: well, apparently these are photo resistors, which are much slower and could in fact have substantial transition times (brief lookup indicates 10ms), so could definitely be relevant.