@tubetime @adistuder @brainwagon If the units are discrete (increments of 0.01 cm) then there are 256 possible values of length from 0.00 cm up to 2.55 cm. 2.56 cm would be 0x0100.
If the units are continuous (not integers) then it would range from 0.00 ≤ length < 2.56, so length up to but not including 2.56 cm. In this case, answering "how many mm are there in an 8-bit inch" is harder because there are infinitesimally less than 256, and also sort of inaccurate because that's not really 8 bits.